- test-drb@ccmp.vtda.org - classiccmp.org

by jpl15＠netcom.com

At the risk of boring the Regulars (please forgive) I would like to take some bandwidth to extend an invitation to any Classiccmpers who will be in the Southern California area this coming weekend, the 24th of April, 99..... The TRW Ham Radio and Electronics swapmeet will be held at the TRW facility in El Segundo, Ca, from 7:30am until 11:30am local time.

26 years, 10 months

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Need PDP boards identified

by CLASSICCMP＠trailing-edge.com

>I need some help identifing some of the boards that I pulled out of Paxtons >yesterday: > > M7904 - Not listed in the Field Guide > Hex-Height > 40-pin ribbon cable sticking out the side This is one of the five boards (M7900-M7904) in the RK06 system unit. This particular board contains the drivers for the actual drive interface. > NDLV-11 > netcom products, inc. > copyright jan. 1979

26 years, 10 months

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Ancient disk controllers

by ethan_dicks＠yahoo.com

--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote: > > > Which pins are used on the 50 pin connector? Could it be pinned out as a > > > SCSI port. Or is it possibly some custom host interface? > > > > It could be a custom host interface. Among other anomalies, I don't see > > any terminating resistors. > > Doesn't sound like SCSI/SASI, then... > > > Can you scan that data sheet or send me a photocopy? I'd pay for > > copying/mailing. > > Sure, but from what others have said, I don't think it'll be a lot of use > to you. Well... does anyone need this? I happen to have the enclosure that goes with it too. It says "Davong" on the outside and has a one-piece lid with broad, rounded corners, not boxy. > > > 20MHz/4 = 5MHz = standard ST506 data rate. > > > > Right. It's the right rate for an 8" disk. > > Is it? I thought the 8" winchesters had a 4.34MHz data rate. To repeat myself, that's a typo. I meant to say "...not the right rate...". Mea culpa. If anyone can put this to use, let me know. I can't imagine anything I'll own in the near future that needs it. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 10 months

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Apple HAL XEBEC controller

by pete＠dunnington.u-net.com

On Apr 18, 11:58, Sellam Ismail wrote: > Can you scan this card and the Xebec interfaces you have and post a > picture of them somewhere? I then might be able to tell you if you've got > a winning combination. Sadly, that's one of the projects that's "less than complete" at the moment. > Ok, I just took stock of the hardware in my next room. I have a First > Class Peripherals Sider ][ hard drive (actually two) and for the first > time ever noticed that they have a Xebec label on the bottom, which I > guess means these are actually Xebec hard drives and First Class was the > name they sold hard drives under? Whatever. I didn't know Xebec made drives, but it's perfectly possible. They used to describe themselves as the "Zero Defect" company, so that would fit. > Ok, so then I opened one up and noticed a Xebec PCB that is the same size > as a 5.25" drive, that contains among many other things a Z80, an 8502 and > a ROM with a Xebec label. The connector is 50 pins. Sounds just like mine. > I then opened the Apple //e hood and the Xebec controller card also has 50 > pins. Ah. Well, I didn't really expect you'd have a setup that was quite the same. Thanks very much for taking the trouble to check, though. > So I'm not familiar with the card you have at only 26 pins. > > > Was there a standard pinout on Apple SCSI/SASI boards? Perhaps it's the > > same as the Mac 25-pin SCSI? > > If you consider Xebec to be the standard then yes. I've never seen a hard > drive controller made by any company other than Xebec. Hmm... I've seen lots, notably Adaptec and Xylogics... but perhaps you mean in an Apple environment -- in which case the only other name that comes to mind is Corvus, and I've no idea what they used. Not SCSI, I think. Still, I've got a few ideas, so tomorrow I'll go and dig out the Mac manuals and look at their 25-pin interface, and check some of the traces on the Apple board to see if there's a plausible match. -- Pete Peter Turnbull Dept. of Computer Science University of York

26 years, 10 months

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Need PDP boards identified

by healyzh＠aracnet.com

I need some help identifing some of the boards that I pulled out of Paxtons yesterday: M7904 - Not listed in the Field Guide Hex-Height 40-pin ribbon cable sticking out the side NDLV-11 netcom products, inc. copyright jan. 1979 MSI-11 (c)1978 Andromeda Systems Inc faded sticker on handle says 'MUX1' and 'MUX3' the rest is to faded to read A two board set from Plessey Peripheral Systems connected via a 50-pin ribbon cable. The top board (P/N 703580) has 8 LEDs and a 10-pin connector. The bottom board (P/N 703570) has 4 26-pin connectors and a roughly 66-pin connector (not sure its exact size). The only thing I can think of is some kind of drive controller. Zane | Zane H. Healy | UNIX Systems Adminstrator | | healyzh(a)aracnet.com (primary) | Linux Enthusiast | | healyzh(a)holonet.net (alternate) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | and Zane's Computer Museum. | | http://www.dragonfire.net/~healyzh/ |

26 years, 10 months

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Program Challenge (was Re: z80 timing... 6502 timing)

by yakowenk＠cs.unc.edu

You'd normally expect that the winner of any such contest would be the most recent processor, wouldn't you? So, if the cut-off date was 1982, any processor that was released in late '82 should probably beat any that was already available in 1979. Of course, if the 1979 processor had a much faster version available in 1983 (like a higher clock rate), that faster version wouldn't be legal with the 1982 cut- off, because that wasn't around in 1982. So, I suggest that one way of judging cleverness of software hacks is that they let an older processor beat a newer one. Judging that way, we don't even need a cut-off date. But anybody coding for a 1999 processor won't have any way to win. Of course, then we need clear evidence when each processor became available at each clock speed, and we can argue about when the chip was *really* available (as opposed to being orderable, or just having the spec available). Bill.

26 years, 10 months

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Need PDP boards identified

by danburrows＠mindspring.com

> M7904 - Not listed in the Field Guide > Hex-Height > 40-pin ribbon cable sticking out the side M7904-00 RK611 DRIVE INTERFACE,HEX > NDLV-11 > netcom products, inc. > copyright jan. 1979 More than likely another DLV11 clone. It is amazing how many different ones I have encountered. > MSI-11 (c)1978 > Andromeda Systems Inc > faded sticker on handle says 'MUX1' and 'MUX3' the rest is to > faded to read http://www.andromedasystems.com/ if all else fails >A two board set from Plessey Peripheral Systems connected via a 50-pin >ribbon cable. The top board (P/N 703580) has 8 LEDs and a 10-pin >connector. The bottom board (P/N 703570) has 4 26-pin connectors and a >roughly 66-pin connector (not sure its exact size). The only thing I can >think of is some kind of drive controller. The MMI has a few listed and has them described as memory module.

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

Yes, but there were three versions, at least, one being the Rockwell, one being the MOS-Technology , and the third was the Synertek/Western Design Center version. The VLSI Systems version was different from the Rockwell, but I don't know whether it was a completely different one or whether it fell in with one of the others. UMC made one, as did MITSUBISHI, however. I don't know where they fit in either. Do you? Dick -----Original Message----- From: Sellam Ismail <dastar(a)ncal.verio.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 3:14 PM Subject: Re: z80 timing... 6502 timing >On Sat, 17 Apr 1999, Allison J Parent wrote: > >> The 6502 series ahd all sorts of undocumented opcodes and they tended to >> change with later versions. > >The 65C02 version effectively ended the regular 6502 undocumented opcodes >since it added a few new instructions and some new addressing modes for >existing instructions that took on the opcodes of some of the previously >undocumented ones. > >Sellam Alternate e-mail: dastar(a)siconic.com >--------------------------------------------------------------------------- --- >Don't rub the lamp if you don't want the genie to come out. > > Coming this October 2-3: Vintage Computer Festival 3.0! > See http://www.vintage.org/vcf for details! > [Last web site update: 04/03/99] >

26 years, 10 months

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z80 timing... 6502 timing

by allisonp＠world.std.com

<Wow, you have a TMS1000 based micro? What the heck is it? ;) Kids... TMS1000 was a 4bit single chip cpu from the 70s aand it was used to make toys, games and even timers for microwaves. A system around that chip might be a phone with memory and redial or a VCR timer. It did not have an external address or data bus nor were there eprom versions. I have numerous products with tms1000, COP4, uCOM4, uCOM75 series single chip CPUs. Allison

26 years, 10 months

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Apple HAL XEBEC controller

by pete＠dunnington.u-net.com

On Apr 17, 12:26, Richard Erlacher wrote: > Subject: Re: Apple HAL XEBEC controller > Xebec made a number of "specialized" bridge controllers, which fit between > the host adapter, which is what you've described, in this case possibly > intended to go to a compatible version of their 14xx-series controllers > which, in turn, provides a SCSI interface to an ST506 drive, which you > apparently have on hand. Yes, though AFAIK all the Xebec controllers of that era are SASI, not SCSI. > It is likely that the 26-pin connector is to the Apple II version of SCSI > which was put out back then on a 25-pin DB-25 connector. Sounds logical. Anyone got the pinouts? -- Pete Peter Turnbull Dept. of Computer Science University of York

26 years, 10 months

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OT: Religious Festivals (was:Re: Fwd: H8 Enthusiasts)

by Philip.Belben＠pgen.com

> Just back from Warschau (Poland) - Thanks. And BTW: since Karfreitag Where? Oh, you mean Warszawa. Warsaw. ;-) > (Easter Friday sp?) I'm a proud owner of a H8 - I went to Swizerland The Friday before Easter is called Good Friday. I've never managed to work out what "kar" means in your name for it. My favourite, though is Ascension, which I understand you call Himmelfahrt... > with an empty car an came back with some kind of a wight problem, > including an H8 and an Compupro 286 (an S100 286 wit 4 Z80), just > to find aout that I had no Swiss power adaptor at hand (thy use a > different connector)... Sounds fun! Philip.

26 years, 10 months

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Memory feature ?

by lwalker＠mail.interlog.com

While browsing I ran across a post which set me giggling. It was from a Power Mac user who was fed up cause his 200mhz 192Meg machine kept coming up with "out of memory" errors. In the replies it was stated that OS 8.1 and 8.5 were known to have "memory leaks". Heh, heh, heh. I'm reminded of the 4k memory in my Vic-20 or Gates' oft-quoted statement regarding the more than enough 640k MSDOS. ciao larry lwalker(a)interlog.com Collectors List and info http://members.xoom.com/T3C

26 years, 10 months

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How to read recalcitrant floppies?

by mike＠delos.rain.com

On 17 Apr 99, at 11:52, Ethan Dicks wrote: > Are there any tools to go divining on DOS floppies that work better than > an endless succession of "R"etries? There's a new program called Lost and Found that's supposed to be able to recover data from problem disks. I haven't actually used it myself, but you can read the manufacturer's claims at www.powerquest.com. ----------------------------------------------------- Mike Newman INTERNET: mike(a)delos.rain.com Aloha, Oregon USA -or- mikewnewman(a)earthlink.net http://home.earthlink.net/~mikewnewman ----------------------------------------------------- I met a mine foreman who has a piece of coal with a 1909 gold sovereign in it. I saw an ammonite, apparently squashed in the fossil footprint of a sandal.

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

Because of unbelieveably foolish, inane, silly comments like the one you just made, the investigative nature of this problem has been pushed aside if favor of what's really just a game. You've already admitted that you don't even have the totally irrelevant processor you initially claimed you'd use, not that it matters, since that comparison is of no value or interest with respect to the problem at hand. Just read the subject of the email you've been answering. I'm not interested in getting into the equivalent of a virtual computer "tractor pull." I can leave that to the rednecks with the room-temperature IQ's without feeling any loss. However, since the late 1970's there's been this nagging question about the relative merits of two essentially opposed approaches to computer architecture, and a serious attempt to make a comparison without the underlying motive of trying to sell hardware or software has really never been made. I suppose it's because it really doesn't profit anyone to make this comparison at this juncture, except perhaps the incipient 12-year-old lurking within us all. Your comparison would be accurate, perhaps, if it took only a couple of days' effort and parts we all probably have lying about anyway to build that formula-1 car you refer to, but if a person wants to perform a valid test, there has got to be suitable hardware. Now, there are lots of plain-vanilla-flavored microcomputers with a Z-80 at their hear. However, almost all the 6502-based computers were really designed for the video-toy market and only find themselves able to serve as computer only as an afterthought. The Apple-II is probably a prime example. It would be acceptable to run a comparative exercise on the two processors if some valid basis for the comparison could be determined. Hans Franke came up with a proposed means for evaluating the validity of each arrangement. Unfortunately, this requires a test system be prepared, with a suite of test software and some specialized hardware. It also requires that each system-under-test be equipped with compatible hardware. I find this proposal valid, but quite a way off the mark, in that it makes the test almost completely hardware dependent. My take on this test would be to permit development and execution of the algorithm ultimately deemed most appropriate for this test on whatever hardware the programmer has at his/her disposal. It should be as limited in its hardware requirements as possible, i.e. it should not matter whether the program is written for a TIMEX Sinclair, or a CRAY MPX with simulation capability. The sum total of the resources involved in the code limited to an amount of memory common to all the contestant systems, and a console interface common to all as well. Code for interacting with the system console need not be considered, so long as it is entered with a call to a routine requiring NO preparation prior to the call. That means you must call a routine to make the console I/O preparations before calling the console I/O routine itself. The time for the first call and return made within the contestant's code is to be included in the competition, but subsequent action is not. However, the called console I/O code must be provided in order to show that no task-related effort is being made by the console handling routine. This is simple with a terminal, but not so simple with a device having resident video and keyboard I/O. Hans Franke suggested this test be performed on a system like the KIM-1. It is probably achievable in one. It must be so limited that no one system can outperform another just because of its resources. The comparison is between the processors, not the systems in which they reside. The code applicable to the contest can be evaluated for its consumption of processor cycles and relative timing computed from that. However, a lowest common denominator with respect to resources must be applied in the strictest sense. All of this monitoring and calculation can be eliminated, however, if each contestant simply builds a simple system with a full compliment (whatever that is determined to be) of memory, and both of the subject processors can use only 64K of memory. The resources implicit in the processor design shouldn't be an issue as that's part of what's being compared. Consequently it must be inherently permissible to use as much stack as needed without being penalized in any way, provided that falls within the designated limits. Again, such limitations go away if everybody runs their processor in 64K of RAM/ROM with only the one I/O device. Doesn't this make more sense than having a "tractor-pull" between computers? Dick -----Original Message----- From: Sellam Ismail <dastar(a)ncal.verio.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Sunday, April 18, 1999 12:10 AM Subject: Re: z80 timing... 6502 timing >On Sat, 17 Apr 1999, Richard Erlacher wrote: > >> I want to distance myself from the majority of this nonsense. Building a > >Well, since you launched us all into this nonsense its pretty hypocritical >of you to want to back away from it now. > >> simple computer with a processor, a ROM, a full compliment of RAM, and a >> serial console interface is a 10-minute design and a 90-minute fabrication >> task. If it's designed to fit already existing firmware/software, it's even >> more or less practical to fit it into that firmware or software's >> understanding of what the hardware is that fits with it. That means that an >> operating system might be straighforward to accomplish in a day or two if >> there's software in the form of a decent monitor or OS to support it. > >Sure! Let's have a driving contest to see who can drive the fastest, but >first we all have to build our own cars. THAT MAKES AN AMAZING AMOUNT OF >SENSE! > >> implementation. I'm sure most people in any way familiar with the things we >> had to do back in the '70's will agree, that, from a hardware standpoint, >> building a single-board system with 64K SRAM, Whatever size of EPROM you >> like, overlapping it and disabled when copied into RAM, and a serial port is >> a no-brainer, requiring , as I previously said, about 90 minutes to >> wire-wrap. It might take longer if you have to find the parts. If you use > >Sure, and open heart surgery is a pretty straightforward operation for an >experienced doctor, but we're not all experienced doctors. > >Dick, you're amazing. > >Sellam Alternate e-mail: dastar(a)siconic.com >------------------------------------------------------------------------------ >Don't rub the lamp if you don't want the genie to come out. > > Coming this October 2-3: Vintage Computer Festival 3.0! > See http://www.vintage.org/vcf for details! > [Last web site update: 04/03/99] >

26 years, 10 months

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Apple HAL XEBEC controller

by pete＠dunnington.u-net.com

On Apr 18, 4:51, Sellam Ismail wrote: > Oops, sorry. I misread that. I'll let you off :-) I do that all the time... > > looks like it's just boot/driver code, so I think there must be some other > > way to format the (winchester) drive. > > You are correct. Generally the Xebec interfaces were used with the Sider > hard drives (at least those are the only drives I've ever seen them > used with) and they came with utilities on floppies for partitioning and > formatting the drive. I've seen Xebecs with all sorts of drives (but not on Apples). But unlike Adaptec SCSI copntrollers, the Xebec ones never stored the drive geometry on the drive, so you had to put it in a file to be read by your code (or hardwire it into your code, which is a bit limiting). I remember writing a pile of 6502 code for a BBC Micro to handle that. > I don't think this is SASI since the actual hard drive is a ST-225 or > equivalent. More like MFM. Well, sure, the drive would be MFM (or whatever the particular Xebec controller was intended for). I don't have the Xebec controller that came with this particular Apple interface; I was just hoping I could use this Apple interface with one of the spare Xebecs I have in the junk box. > I don't think I have the pinout, but then my > Sider manuals are stored away somewhere, and I don't know that they would > necessarily have any technical info for the Xebec card. > > Are you wanting to use it to hook a hard drive up to your Apple ][? Yes. I should have been clearer; I have the Apple-to-Xebec interface, and a couple of Xebec SASI controllers from elsewhere, and a few MFM drives. What I need is the pinout of the 26-pin connector on the Apple-to-Xebec interface, so I can figure out if my Xebex will connect to it. I wonder if an Adaptec ACB4000 would work? I've got a couple of those, too. Was there a standard pinout on Apple SCSI/SASI boards? Perhaps it's the same as the Mac 25-pin SCSI? -- Pete Peter Turnbull Dept. of Computer Science University of York

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

Well, you'd have to be careful to avoid mixing up the timing in the system intrinsics to be "postulated" and the contest-specific code. How would that be handled? Dick -----Original Message----- From: Sean 'Captain Napalm' Conner <spc(a)armigeron.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 3:14 PM Subject: Re: z80 timing... 6502 timing >It was thus said that the Great Mike Ford once stated: >> >> >Ooh! A machine code competition. I'm in! I'll do the 6502 and whoop >> >EVERYONE'S ass! >> >> And then you woke up. First what are the rules, 6502 or 65C02, code in Rom >> or Ram, what is the code supposed to do? >> >> My vote goes for something with some graphical element so we can "see" what >> is happening. (spinning ball, etc.) > > I would vote against that because the hardware available might make a >difference. For instance, moving an object on a 6502 based system, the C-64 >will probably win both the speed and size catagories, simply because of >hardware assist. Besides, if this is to match code/speed size between CPUs, >then not all machines are capable of graphics. > > The Roman Numeral one sounds interesting. To make it fair, I would assume >that there exists a routine, CHROUT, that takes as input the character in >the main accumulator and displays it on the output device. The output >device is a simple TTY like device that supports TAB, CR (which returns the >print head to the start of the line, and advances to the next line) and BS. > > The code for CHROUT is NOT to be counted towards speed or size, but I'd >probably allow the call to CHROUT to be considered. > > Contest open for any CPU anyone would care to write code for. > > -spc (Hows that for a contest?) >

26 years, 10 months

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Filler panels for a DEC MINC-11?

by jimw＠agora.rdrop.com

The subject just about says it all... I just rescued one from the Paxton auction, and one of the filler panels in the lab module section is missing. Anyone got a spare? (or some neat modules? or some docs... or....) -jim --- jimw(a)computergarage.org The Computer Garage - http://www.computergarage.org Computer Garage Fax - (503) 646-0174

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

If one were going to put an FDC in place, the easiest probably would be the WD3765, since it has built in cable-drivers and receivers as well as clock/data processing hardware. You connect it directly to the cable, as I recall. It otherwise behaves as a uPD765 (i8272). Dick -----Original Message----- From: Allison J Parent <allisonp(a)world.std.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 10:06 PM Subject: Re: z80 timing... 6502 timing ><Western Digital disk controllers are a little harder to get, so I'd ><change it to 'a disk controller of your choice' which means you can use ><an 8272 or whatever (trivial to get off an old PC card). > >1793s are common enough and cheap too. If I went with the 765 (8272) >I have to claim unfair advantage! > ><Considering you can make a serial port in a couple of chips, this is not ><a major design task.... > >But it's overhead is trivial and well enough understood as to mean little. > >IT would be more of a challenge if each person supporting a processor had >to use a different one. That would be a true learning experience. > >As to hardware... I cheat. I have SBCs for most common cpus. > >1976 imp48 8048 (cute little sbc with tape IO, TTY, relays) >1977 8048 from byte 8048 (this was an 8035 with a mini front pannel) >1980 8051 8751 (basically a 8051 SBC with monitor) >1978 SC/mp ISP8A500 (sc/mp I) >1979 National TBX 8073 (SC/MP II with tiny basic) >1977 COSMAC ELF base 1802 (quest board) >1976 6800d1 6800 >1977 kim1 6502 >1983 Telvideo 905 R65c02 (card from terminal, good as SBC!) >1978 8x300 proto 8x300 (signetics) >1981 SDK78 7800 (nec propritary) >1981 78pg11 Protoboard 78pg11 (NEC propritary) >1979 Tk80 8080 >1980 explorer8085 8085 (base card has 8085, ram and rom) >1980 Computime CPUZ z80 (s100 card with 1k ram, serial, eprom z80) >1981 Vt180 Z80 (z80, 64k, 4 serial, FDC, Eprom, RTC) >1981 Hurikon MLZ92 Z80 (Z80, mmu, 64k ram, eprom, serial,FDC) >1978 INtersil sampler (6100, 256w ram, rom, serial) >1982 29116 proto 29116/2911 proto for bitblitter >1982 Z8001 proto z8001 (z8001, 16k ram, 16k eprom, serial) >1982 Falcon T-11 (pdp11 chip, ram, parallel, serial, rom) >1979 SSS technico TI9900 (9900, ram, rom, serial) >1986 Advice 78032 (uVAXII, serial, 96k ram, 512k rom) > The advice was used in 87 to assist the MV2000 design! > > All are classics, only the Advice wasn't available in '83. > > Now if I wanted to get exotic, I have a load of 2901/2911s with date > codes pre 1980. Also 29116s (pre 83). Also enough raw 8748/9 and 8751 > parts to do a major hack (maybe 50 or 60 of each). the 8749s are the > slower 1982 parts that only run at 11mhz (instruction cycle time of > 1.36uS) However with the prior to 1982 limit sthere are no sortage of > choices. > > I'm not above using multiple cpus to do the task or mixing several > different ones. > >Allison >

26 years, 10 months

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shipping floppy disk drives

by yakowenk＠cs.unc.edu

I'll be shipping a few floppy disk drives soon, and want to minimize the shipping damage to them. So, is it better to ship them with the drive door open or closed? And with or without a floppy inserted? Bill.

26 years, 10 months

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Ancient disk controllers

by ethan_dicks＠yahoo.com

--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote: > > The final connector, J6 is 50 pins. > > > Which pins are used on the 50 pin connector? Could it be pinned out as a > SCSI port. Or is it possibly some custom host interface? It could be a custom host interface. Among other anomalies, I don't see any terminating resistors. > For example I > have here the data sheet for the WD1001 controller. It uses essentially > the chipset you mentioned. It has a 50 pin host connector, but it sure > ain't SCSI. Can you scan that data sheet or send me a photocopy? I'd pay for copying/mailing. > 20MHz/4 = 5MHz = standard ST506 data rate. Right. It's the right rate for an 8" disk. > 8MHz is a common enough clock for the 8x300 series of CPUs as well. OK. > What bothers me, if this _is_ a SCSI controller is that there seems to be > no way of setting the device address. No place that I can see. > My guess is that it's a sort-of WD1001 clone. OK. That makes sense. In fact, when I read the recent debates of WD1001's, I thought of this board. I didn't think I could find it as fast as I did. It could have been packed a lot deeper than it was. Thanks for the insights. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 10 months

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Dumb OS question

by CLASSICCMP＠trailing-edge.com

>I recently found an ancient copy of QNX, which seems to be a light unix like >OS. > >Looking on the WEB, I found that current versions are still around, but >marketed as a "Real Time" OS. The 80's documentation I have says nothing >about real time. > >My dumb question: What is a real time operating system? It's not a dumb question! It is, in some respects, a very controversial question. In very general terms, a real time operating system is what is used when a response from the computer to an external event is required in a "timely" fashion. For example, if it's a fly-by-wire jet, and the pilot pulls the control stick back, you don't want the computer to delay in making the control surfaces move because the co-pilot is doing some lengthy navigational or fuel consumption calculations at the same time. For a multi-tasking operating system, this generally means two things: 1. When an external stimulus comes in, there has to be some way of making sure it will interrupt tasks of lower priority. 2. After the higher-priority task is started, it has to finish in a fairly predictable amount of time. Depending on the nature of the real-time task and/or the person defining "real-time", you also often find some further requirements. There are also folks who split the definition into "soft real-time", where it's OK if you're occasionally late with an answer or occasionally take too long to respond, and into "hard real-time", where the computer is never ever allowed to be late in responding or answering. Traditional Unices are not, by any measure, real-time operating systems. There are Unix-like OS's that are called "real-time operating systems", but many of the "hard real-timers" will disagree with this. A more modern approach to "real-timeliness" considers not only the main CPU, but also subsidiary CPU's and systems. For example, if a response to a stimulus requires doing any disk reads or writes, you may need to thoroughly know the worst-case response time of the disk drive. Modern disk drives (or even many disk drives from a decade ago) have microprocessors in them and for a truly safety-critical application it may be necessary to thoroughly review and qualify the firmware that's in the disk drive to be sure that it will always respond in a certain minimum amount of time. Some real-time operating systems can be pressed into service as general-purpose multi-user OS's. For example, RSX-11M. Others make quite nice single-user development platforms - for example RT-11. Modern network-in-the-kernel OS's are very difficult to turn into "real-time" systems with much functionality. You ever have a NFS server go down and tie up a campus full of workstations for minutes at a time? -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

26 years, 10 months

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FWD: Items on auction of possible interest

by rhblake＠bigfoot.com

Do not get in touch ith me on these but rather see them on eBay and contact the seller. I know the seller and that the profits from these items get turned into donations to a group known as Ky Industries for the Blind (KIB) so that they can purchase keyboards, ram and monitors for machines they build from donations for those with sight impairments, and occasionally others with other disabiliies. _____________________________________________________________________ Rick Mayes <rmays43(a)yahoo.com> Leitchfield, KY USA - Saturday, April 17, 1999 at 17:38:53 I have the following oldies but goodies at www.Ebay.com item number title 92355306 Hewlett Packard 86, CPU, dual 5-1/4" floppy 92353685 Apple II PLUS, CPU, dual 5-1/4" floppy drive 92350927 Apple IIe, CPU, dual 5-1/4" floppy drives 92348416 6 Diablo HyType II Multistrike Film, ribbons 92251130 MacIntosh SE, CPU/Monitor 92248010 Hewlett Packard, HP 71B Mini Computer 92246567 COLORADO 250 MB Tape Back UP Drive Would the fellow that needs a ST-225 HD please email me I have one for you for whatever the shipping will be. Thanks, Rick

26 years, 10 months

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CP/M as an RTOS (was Re: Dumb OS question)

by allisonp＠world.std.com

<CP/M wasn't bad for its day, and I was rather fond of it at the time <(compared to some of the feeble crap that other companies were putting It still isn't. I run a lot of stuff here using cpm and have a few projects going to add things I feel are missing like hierarchal directories. <out, such as Ohio Scientific's OS-65D), but I'd have to concur with <your assessment of it. Keep in mind that comments of it's being not an OS but a FS is subtle but totally lost of the flamers. <I've provoked some major flames myself by calling MS-DOS a feeble excuse <for a program loader. But in reality I have to admit that MS-DOS is more <functional than CP/M. However, MS-DOS loses if you compare functionality <per byte of memory consumed. By that metric, hardly anything that I've <seen would even come close to DEC's OS/8. Yep! Allison

26 years, 10 months

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z80 timing... 6502 timing

by allisonp＠world.std.com

<If one were going to put an FDC in place, the easiest probably would be th <WD3765, since it has built in cable-drivers and receivers as well as <clock/data processing hardware. You connect it directly to the cable, as <recall. It otherwise behaves as a uPD765 (i8272). < <Dick IT's 37c65, I have them too along with 9266 and a bunch of others I've used. To prove processor speed or implmentation that list of boards I have are sufficient resource for the task. Dog knows why I'd need a floppy to do a coding race. Allison

26 years, 10 months

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shipping floppy disk drives

by pete＠dunnington.u-net.com

On Apr 18, 4:53, Sellam Ismail wrote: > On Sun, 18 Apr 1999, Pete Turnbull wrote: > > If double-sided, then > > open with no disk is fine, so long as the mechanism can't be jolted into > > letting the upper head hit the lower one. This is pretty well true of most > > 3.5" drives, and they're usually shipped like that. > I've seen plastic shipping inserts for 3.5" drives. To be safe, I'd try > to get one of these inserts for shipping the 3.5" as well. Maybe a local > computer store would have some. I've got half-a-dozen bright yellow ones, somewhere. I once asked why Sony stopped shipping drives with them and was told it was unnecessary; I suspect it just saved money. I'd suggest soft card is better -- the point is to stop the brittle ceramic heads banging into each other and possibly chipping. -- Pete Peter Turnbull Dept. of Computer Science University of York

26 years, 10 months

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All this OT stuff...

by steverob＠hotoffice.com

On Saturday, April 17, 1999 7:43 PM, Christian Fandt [SMTP:cfandt@netsync.net] wrote: > Upon the date 12:02 AM 4/17/99 -0700, Bruce Lane said something like: > > > > > HOWEVER -- Am I the only one getting -really- fed up with all the 'OT:' > >and 'Re: OT' subject lines and off-topic messages? > Ditto! Steve Robertson - <steverob(a)hotoffice.com>

26 years, 10 months

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shipping floppy disk drives

by pete＠dunnington.u-net.com

On Apr 17, 22:32, Bill Yakowenko wrote: > Subject: shipping floppy disk drives > I'll be shipping a few floppy disk drives soon, and want to minimize > the shipping damage to them. So, is it better to ship them with the > drive door open or closed? And with or without a floppy inserted? If they're single-sided, it doesn't matter much. If double-sided, then open with no disk is fine, so long as the mechanism can't be jolted into letting the upper head hit the lower one. This is pretty well true of most 3.5" drives, and they're usually shipped like that. On some 5.25" drives, though, the door or lever could be moved, so inserting a floppy and closing the door may be better. I'd suggest putting it in back-to-front (or use a sheet of thick card with a hole in the middle) to improve the cushioning effect. -- Pete Peter Turnbull Dept. of Computer Science University of York

26 years, 10 months

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Apple HAL XEBEC controller

by pete＠dunnington.u-net.com

On Apr 17, 13:57, Sellam Ismail wrote: > Subject: Re: Apple HAL XEBEC controller > On Sat, 17 Apr 1999, Pete Turnbull wrote: > > > Does it need any other software (like a formatting disk)? The on-board 4K > > EPROM contains only the strings "(C) HAL COMPUTERS LTD 1983", "A/XHAL > > SHARED RESOURCE WINCHESTER SYSTEM", "NOT CONNECTED", and "SRS ERROR", so I > > guess there would have been a floppy with it, originally. > > What in these strings leads you to believe it would have been connected to > a floppy? It was strictly a hard drive interface. Erm, nothing, Sellam. I *didn't* suggest it could *connect* to a floppy drive; I think there may have been a supplementary floppy disk containing (at least) a formatter, since those are the *only* strings in the ROM. It looks like it's just boot/driver code, so I think there must be some other way to format the (winchester) drive. I know you have a lot of Apple ][ stuff. Anything like this? Do you have a pinout for any contemporary Apple ][ SASI/SCSI interface? -- Pete Peter Turnbull Dept. of Computer Science University of York

26 years, 10 months

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Ancient disk controllers

by ethan_dicks＠yahoo.com

--- Richard Erlacher <edick(a)idcomm.com> wrote: > see below, please. > > Dick > > -----Original Message----- > From: Ethan Dicks <ethan_dicks(a)yahoo.com> > >> 20MHz/4 = 5MHz = standard ST506 data rate. > > > >Right. It's the right rate for an 8" disk. > > > Nope, it's not! the right rate for 8" Winchesters is 4.34 MHz! Damn! Typo. I *know* that the 8" disk transfer rate is below 5Mhz. The recent coverage of the WD-1001's were quite explicit in that regard. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 10 months

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OT Was z80 timing... 6502 timing

by jax＠tvec.net

>Ooh! A machine code competition. I'm in! I'll do the 6502 and whoop >EVERYONE'S ass! > Wait just a minute..... Since we have been discussing various "ethnic" pronunciations, I am compelled to point out that this statement may be interpeted differently than intended. As a born\bred survivor of the land of redneck, pickup truck, and chewing tobacco, I assert that a "whoop" is a loud yelling type of activity. The execution of which on someone's posterior will bring a certain confusion to your enemy ( he will think you are a fruit ), but will not render him defeated. I laughed so hard at this mental image it made me hurt. :) Try "whup" next time, as in "opening a can of whup-ass". My 2 centavos from the Republic of Texas. BTW, my money's on Tony. jax(a)tvec.net

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

Kindly give the comments interleaved with your quoted message below a look. Dick -----Original Message----- From: Sellam Ismail <dastar(a)ncal.verio.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 2:45 AM Subject: Re: z80 timing... 6502 timing >On Sat, 17 Apr 1999, Mike Ford wrote: > >> >Ooh! A machine code competition. I'm in! I'll do the 6502 and whoop >> >EVERYONE'S ass! > Rules are a problem, aren't they? > >> And then you woke up. First what are the rules, 6502 or 65C02, code in Rom >> or Ram, what is the code supposed to do? > Well . . . There's the problem . . . first of all, the code's got to be executable on something everyone has got available, or it's got to be simulated on a simulator everyone has available, else there'll be a limit on interest right away . . . Then, shouldn't there be some consideration of the coding/debugging time involved? I'd lean in favor of a PC-compatible simulator. That makes the computation of actual execution time straightforward. . . and, of course, it's got to run the code on a "real" processor, not just a putative "we could build . . ." sort of thing, right? . . . well, maybe . . . Then there's the question about WHICH 6502 to use. Given a listing, it's easy enough to compute how long it takes the code to run, but which instruction set? What about undocumented features? Both these processors were famous for those. Of course, there doesn't have to be a limitation, i.e. one could consider ALL available cores. I'd propose it be a significant problem, but one which is well-defined, i.e. algorithms are published, hence the problem solution is well-defined, and I'd propose further that the same algorithm be used so we compare "apples with apples." As for the processor core, well, it's also got to be one everybody's got available, yet it wants to be one which WAS available in 1982. That might include the Synertek, MOS, and MAYBE the Rockwell core. We can't just say 65C02, because it was buillt in several conflicting versions. What about the Z-80 core? Whose? Which one? Speed, of course, should be "limited" to whatever was available in 1982. That certainly includes the Synertek (MOS Technology-comptible)"4MHz" 6502C (always worked fine at 5 MHz by then), as well as the Zilog Z-80B (6-MHz). Was the 8MHz part out in 1982? > >> My vote goes for something with some graphical element so we can "see" what >> is happening. (spinning ball, etc.) Whereas this might be "cute" it is very limiting, in that it has to be a graphics-capable environment available with both processors. It should not "fall" conveniently for either processor, so the graphics array should be large, and, AFAIK there's no such system for either processor. What should be done, here? Should we build a board? How do we measure how fast it's going? Remember, the hardware environment has to be more or less the same for both processors. >BRING IT ON, MO FO! > >Sellam Alternate e-mail: dastar(a)siconic.com >--------------------------------------------------------------------------- --- >Don't rub the lamp if you don't want the genie to come out. > > Coming this October 2-3: Vintage Computer Festival 3.0! > See http://www.vintage.org/vcf for details! > [Last web site update: 04/03/99] >

26 years, 10 months

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Ancient disk controllers

by edick＠idcomm.com

see below, please. Dick -----Original Message----- From: Ethan Dicks <ethan_dicks(a)yahoo.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 8:17 PM Subject: Re: Ancient disk controllers > > >--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote: > >> > The final connector, J6 is 50 pins. >> > >> Which pins are used on the 50 pin connector? Could it be pinned out as a >> SCSI port. Or is it possibly some custom host interface? > >It could be a custom host interface. Among other anomalies, I don't see >any terminating resistors. > >> For example I >> have here the data sheet for the WD1001 controller. It uses essentially >> the chipset you mentioned. It has a 50 pin host connector, but it sure >> ain't SCSI. > >Can you scan that data sheet or send me a photocopy? I'd pay for >copying/mailing. > >> 20MHz/4 = 5MHz = standard ST506 data rate. > >Right. It's the right rate for an 8" disk. Nope, it's not! the right rate for 8" Winchesters is 4.34 MHz! >> 8MHz is a common enough clock for the 8x300 series of CPUs as well. That's true enough. >OK. > >> What bothers me, if this _is_ a SCSI controller is that there seems to be >> no way of setting the device address. > >No place that I can see. > >> My guess is that it's a sort-of WD1001 clone. It predated the WD1001 by some time. >OK. That makes sense. In fact, when I read the recent debates of >WD1001's, I thought of this board. I didn't think I could find it >as fast as I did. It could have been packed a lot deeper than it >was. > >Thanks for the insights. > >-ethan > >_________________________________________________________ >Do You Yahoo!? >Get your free @yahoo.com address at http://mail.yahoo.com >

26 years, 10 months

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Bad form...

by mbg＠world.std.com

... to follow up to one's own posts, but I've done a little more research and I suspect that the Megalink boards are some sort of network board. I had originally been informed that they were some sort of video capture board... Anyway, now all I need to do is get some programming info about them. Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com | | Unix Support Engineering Group | (home): mbg!world.std.com | | Compaq Computer Corporation | addresses need '@' in place of '!' | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 | required." - mbg | +--------------------------------+-------------------------------------+

26 years, 10 months

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How to read recalcitrant floppies?

by marvin＠rain.org

Ethan Dicks wrote: > > I am attempting to back up some floppies from a project I did a few years ago. > The sets of 3.5" 1.44Mb IBM floppies have been stored in a box, in a cool and > dry room. Out of one set of 12 and one set of 15 disks, I have four disks > that have read errors that DOS won't get past, bad sectors and the like. One program I have used with a great deal of success is Spinrite.

26 years, 10 months

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Another identification needed...

by mbg＠world.std.com

I have a few more boards which need identification. Again, the scans can be found at ftp://ftp.std.com/ftp/pub/mbg/scans/computrol_30-0096_7.jpg it is a two-board set. There is an over-the-top connecting cable and a thin cable with a bnc connector on the end. One board is labelled 'Memory Map Megalink 1' and 'dma bus' and the other is labelled 'Memory Map Megalink 2' and 'datacom'. They're qbus boards, but with no switches for setting addresses and/or vectors. Can anyone identify the pair of boards? Thanks in advance... Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com | | Unix Support Engineering Group | (home): mbg!world.std.com | | Compaq Computer Corporation | addresses need '@' in place of '!' | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 | required." - mbg | +--------------------------------+-------------------------------------+

26 years, 10 months

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Ancient disk controllers

by edick＠idcomm.com

My understanding prior to buying these controllers was that they were incompatible with the WD1000 and 1001 series, and were not SASI or SCSI either, thought they purportedly had a similar handshake. Beyond that, I need to find and subsequently read the documents. Dick -----Original Message----- From: Eric Smith <eric(a)brouhaha.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 7:28 PM Subject: Re: Ancient disk controllers >> include a N8X305N processor, some N82S181N ROMs, an N8X371N with leads going >> right to the 50-pin connector, and five socketed WDC parts copyrighted in 1980: >> WD1100V-03, WD1100V-01, WD1100V-04, WD1100V-05 and WD1100V-12. There is a >... >> As I said, I was told when I bought it that it was a SCSI controller. I >> remember trying to use it some years ago and not having much success. Does >> anyone have any info on this oddball? > >Sounds like a clone of the WD1000 or WD1001, which are nowhere close to >either SASI or SCSI.

26 years, 10 months

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z80 timing... 6502 timing

by allisonp＠world.std.com

<Western Digital disk controllers are a little harder to get, so I'd <change it to 'a disk controller of your choice' which means you can use <an 8272 or whatever (trivial to get off an old PC card). 1793s are common enough and cheap too. If I went with the 765 (8272) I have to claim unfair advantage! <Considering you can make a serial port in a couple of chips, this is not <a major design task.... But it's overhead is trivial and well enough understood as to mean little. IT would be more of a challenge if each person supporting a processor had to use a different one. That would be a true learning experience. As to hardware... I cheat. I have SBCs for most common cpus. 1976 imp48 8048 (cute little sbc with tape IO, TTY, relays) 1977 8048 from byte 8048 (this was an 8035 with a mini front pannel) 1980 8051 8751 (basically a 8051 SBC with monitor) 1978 SC/mp ISP8A500 (sc/mp I) 1979 National TBX 8073 (SC/MP II with tiny basic) 1977 COSMAC ELF base 1802 (quest board) 1976 6800d1 6800 1977 kim1 6502 1983 Telvideo 905 R65c02 (card from terminal, good as SBC!) 1978 8x300 proto 8x300 (signetics) 1981 SDK78 7800 (nec propritary) 1981 78pg11 Protoboard 78pg11 (NEC propritary) 1979 Tk80 8080 1980 explorer8085 8085 (base card has 8085, ram and rom) 1980 Computime CPUZ z80 (s100 card with 1k ram, serial, eprom z80) 1981 Vt180 Z80 (z80, 64k, 4 serial, FDC, Eprom, RTC) 1981 Hurikon MLZ92 Z80 (Z80, mmu, 64k ram, eprom, serial,FDC) 1978 INtersil sampler (6100, 256w ram, rom, serial) 1982 29116 proto 29116/2911 proto for bitblitter 1982 Z8001 proto z8001 (z8001, 16k ram, 16k eprom, serial) 1982 Falcon T-11 (pdp11 chip, ram, parallel, serial, rom) 1979 SSS technico TI9900 (9900, ram, rom, serial) 1986 Advice 78032 (uVAXII, serial, 96k ram, 512k rom) The advice was used in 87 to assist the MV2000 design! All are classics, only the Advice wasn't available in '83. Now if I wanted to get exotic, I have a load of 2901/2911s with date codes pre 1980. Also 29116s (pre 83). Also enough raw 8748/9 and 8751 parts to do a major hack (maybe 50 or 60 of each). the 8749s are the slower 1982 parts that only run at 11mhz (instruction cycle time of 1.36uS) However with the prior to 1982 limit sthere are no sortage of choices. I'm not above using multiple cpus to do the task or mixing several different ones. Allison

26 years, 10 months

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OT Was z80 timing... 6502 timing

by allisonp＠world.std.com

<In a _programming_ contest? Surely you jest... (or rather, don't waste <your hypothetical money)... < <Although, if I'm allowed to use _any_ processor, including one I've <designed myself, then things might get mildly more interesting... Oh, I could do that. My spin would be a PDP-8 with hardware of my own making. At one time I had static ram card in an 8e with hacked cpu timing (1uS cycle without trying hard). Then again the list of CPUs I have programmed on is long enough to know which ones to pick for what. Allison

26 years, 10 months

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OT: K&R vs. ANSI C (was: Re: Abort, Retry, Ignore, Fail?...)

by yakowenk＠cs.unc.edu

Actually, yes, I presently maintain (and develop) code for a living.

26 years, 10 months

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shipping floppy disk drives

by SUPRDAVE＠aol.com

In a message dated 99-04-17 22:35:42 EDT, you write: > I'll be shipping a few floppy disk drives soon, and want to minimize > the shipping damage to them. So, is it better to ship them with the > drive door open or closed? And with or without a floppy inserted? ive always shipped drives with a floppy inserted if i dont have the original cardboard/plastic shipping disk. since the heads are clamped down on the disk, supposedly that would minimize damage from movement or rough handling by idiot delivery companies that never treat anything with care.

26 years, 10 months

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Signal detection

by yakowenk＠cs.unc.edu

On 16 Apr 1999, Cameron Kaiser <ckaiser(a)oa.ptloma.edu> wrote: ] ... ] ::Could anyone tell me how a radio detects signals vs. static? There is a ] ... ] Probably signal strength. Undoubtedly really loud static would trip it also ] but your garden-variety radio static just isn't that loud. It's a shame that wouldn't work on a mailing list. Getting lots of noise lately. :-/ Bill.

26 years, 10 months

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OT: City Names

by yakowenk＠cs.unc.edu

On 16 Apr 1999, Philip.Belben(a)pgen.com wrote: ] (I have somewhere a Yugoslavian banknote. Everything is written on it in four ] local languages - two using Cyrillic and two using Latin characters. The ] languages are similar enough that AFAIK nothing needs to be said more than ] three times...) Take a look an Indian rupee sometime. Each note is printed in eleven languages, each with its own script. (Though to me, two or three look pretty darn similar to Hindi.) To try and drag this back to a somewhat related topic, we often hear about computers from North America, Europe, Russia, and Australia. But is anyone here collecting machines from any more "exotic" places? Are there any cool classic machines indiginous to any country from the Middle East, Africa, South America, or South or East Asia? It would be nifty to compare architectures that were not just clones or incremental improvements of machines we already know about. Heck, I know Japan produced a lot of their own computers. Were they all clones of machines we know (or vice-versa)? Bill.

26 years, 10 months

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z80 timing... 6502 timing

by ethan_dicks＠yahoo.com

--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote: > > Ok, the environment is any home micro from the 70s or 80s that ran on any > > processor. The more rudimentary the processor, the more points you get. > > I choose the 4004. > > You have a _home micro_ based on a 4004? What the heck is it? I always wanted to implement a binary clock on the 4004. I never got around to it. Has anyone written a 4004 simulator in some flavor of C? (I recall a recent announcement about a simulator in a language other than one that I use on a regular basis). -ethan -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 10 months

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Ancient disk controllers

by ethan_dicks＠yahoo.com

The recent postings regarding old disk controllers has caused me to dig out one I got at Dayton many years ago. I bought it for the external box, something I didn't have at the time... it appears to be a SCSI card, but might be a SASI card. It was made by Davong Systems, Inc., a company I remember from my younger days. The copyright is 1982, but there are chips on it from 1983. On the back are numbers like 0034 REV (J1) K 310026 170. The J1 is scratched out and the K handwritten. The 170 is also handwritten. On the long end in copper is the number 11-000034 REV E. Connector J2 and J1 are together on one side of the long end (J1 is 34-pins with half of them grounds, J2 is 20 pins with pins 2, 4, 6, 8, 12, 16 and 20 grounded). J3, J4 and J5 are in line on a short end, 20 pins each, similar ground pattern to J2. J2 through J5 appear to have connections to a Motorola AM26LS32 and a TI AM26LS31 which I take to be some sort of analog chip. The final connector, J6 is 50 pins. J1 appears to be the control cable for an ST506 drive, J2-J5 appear to be data cables for talking to four drives. The interesting chips on the board include a N8X305N processor, some N82S181N ROMs, an N8X371N with leads going right to the 50-pin connector, and five socketed WDC parts copyrighted in 1980: WD1100V-03, WD1100V-01, WD1100V-04, WD1100V-05 and WD1100V-12. There is a crystal at 20Mhz in the analog section of the board and an 8Mhz crystal by the processor. In the middle of the board are three vias that are labelled as if they are configuration pads, in an inverted-L, labelled "1", "2" and "3", with a "W" above them, As I said, I was told when I bought it that it was a SCSI controller. I remember trying to use it some years ago and not having much success. Does anyone have any info on this oddball? Thanks, -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

I don't really care what's done here, but I thought the object was to see which of the two processors in the "subject" field would make for faster execution of a useful and published algorithm than the other. It's necessary that the algorithm be implementable on similarly equipped platforms, whether they exist physically or not. The limitation is that it must be timed as executed on a device from one of the two processor types in question, and physically available in 1982-83 as that's the time-frame about which the discussion preceding this coding exercise was centered. There's no point in specifying it for an Apple-II, because that one didn't even run the processor at the current maximum rate due to its overlap with video display refresh timing, and because it would involve too much unrelated design and construction effort to come up with a suitable substitute implemented using a Z-80. Consequently I proposed one wire his own computer using the processor, 64K of static ram, and a serial port of some type TBD. Maybe, just for the exercise, a file device, e.g. a floppy disk controller ala WD1770/72 ought to be included. That's got to be hashed out for sure, if it's to be realized in hardware. Problems potentially lie in the path, however, as some of the hardware may be scarce if availalble at all. A suitable port for attaching a terminal or PC ought to be included, but only in its most basic form. That way, when the builder is finished, he has an item he could possibly use for something, should he choose to do so. This can all get to be a mite burdensome when all you wanted was to see what the fastest or most efficient code one could come up with would look like, which I why I suggested a simulator. The only problem with that is that one could then write and assemble code which didn't in reality do what it claimed because the I/O wasn't simulated as well. This requires some more thought. Dick -----Original Message----- From: Sellam Ismail <dastar(a)ncal.verio.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 2:22 PM Subject: Re: z80 timing... 6502 timing >On Sat, 17 Apr 1999, Richard Erlacher wrote: > >> Well . . . There's the problem . . . first of all, the code's got to be >> executable on something everyone has got available, or it's got to be >> simulated on a simulator everyone has available, else there'll be a limit on >> interest right away . . . Then, shouldn't there be some consideration of >> the coding/debugging time involved? I'd lean in favor of a PC-compatible >> simulator. That makes the computation of actual execution time >> straightforward. . . > >Not necessarily. You measure the code based on an analysis of the clock >ticks it uses. This way the competition is platform independent. Of >course a suitably platform independent code spec would need to be >developed. > >> . Then there's the question about WHICH 6502 to use. Given a listing, it's >> easy enough to compute how long it takes the code to run, but which >> instruction set? What about undocumented features? Both these processors >> were famous for those. Of course, there doesn't have to be a limitation, >> i.e. one could consider ALL available cores. > >This would not be limited to the 6502. The idea is to see who can come up >with the most efficient algorithm on any processor. > >Sellam Alternate e-mail: dastar(a)siconic.com >--------------------------------------------------------------------------- --- >Don't rub the lamp if you don't want the genie to come out. > > Coming this October 2-3: Vintage Computer Festival 3.0! > See http://www.vintage.org/vcf for details! > [Last web site update: 04/03/99] >

26 years, 10 months

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Ancient disk controllers

by edick＠idcomm.com

I've got one or two of these DAVONG controllers, as well as some of the documentation. I bought them as spare parts for the Western Digital controllers I liked better. Since they had the 8X305 and the requisite current injection valve transistor (don't ask me about that!. . . it's characteristic of I2L logic, I'm told.) and similar varistors, I thought the couple of bucks for the controllers was worth it. I bought the boxes and supplies for useful applications, though the boxes were odd enough never to find them. If you have questions, I may be able to help, but I've never read the doc on these so be patient. Dick -----Original Message----- From: Ethan Dicks <ethan_dicks(a)yahoo.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 6:18 PM Subject: Ancient disk controllers > >The recent postings regarding old disk controllers has caused me to dig out >one I got at Dayton many years ago. I bought it for the external box, >something I didn't have at the time... it appears to be a SCSI card, but >might be a SASI card. > >It was made by Davong Systems, Inc., a company I remember from my younger >days. The copyright is 1982, but there are chips on it from 1983. On the >back are numbers like 0034 REV (J1) K 310026 170. The J1 is scratched out >and the K handwritten. The 170 is also handwritten. On the long end in >copper is the number 11-000034 REV E. > >Connector J2 and J1 are together on one side of the long end (J1 is 34-pins >with half of them grounds, J2 is 20 pins with pins 2, 4, 6, 8, 12, 16 and 20 >grounded). J3, J4 and J5 are in line on a short end, 20 pins each, similar >ground pattern to J2. J2 through J5 appear to have connections to a Motorola >AM26LS32 and a TI AM26LS31 which I take to be some sort of analog chip. >The final connector, J6 is 50 pins. > >J1 appears to be the control cable for an ST506 drive, J2-J5 appear to be >data cables for talking to four drives. The interesting chips on the board >include a N8X305N processor, some N82S181N ROMs, an N8X371N with leads going >right to the 50-pin connector, and five socketed WDC parts copyrighted in 1980: >WD1100V-03, WD1100V-01, WD1100V-04, WD1100V-05 and WD1100V-12. There is a >crystal at 20Mhz in the analog section of the board and an 8Mhz crystal by >the processor. In the middle of the board are three vias that are labelled >as if they are configuration pads, in an inverted-L, labelled "1", "2" and >"3", with a "W" above them, > >As I said, I was told when I bought it that it was a SCSI controller. I >remember trying to use it some years ago and not having much success. Does >anyone have any info on this oddball? > >Thanks, > >-ethan > >_________________________________________________________ >Do You Yahoo!? >Get your free @yahoo.com address at http://mail.yahoo.com >

26 years, 10 months

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z80 timing... 6502 timing

by allisonp＠world.std.com

<65C02, because it was buillt in several conflicting versions. What about <the Z-80 core? Whose? Which one? Speed, of course, should be "limited" t <whatever was available in 1982. That certainly includes the Synertek (MOS In 1982 all of the z80s in the market had the same hidden features including the IX/IY 8bit ops. I know of no z80 that didn't have them. Not all of them were available to the 6mhz spec though many could be pushed. Also allowed is the 8085 (available as a 5-6mhz part then). Again all of the 8085s had the extra unsupported instructions as they were deem important! Allison

26 years, 10 months

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How to read recalcitrant floppies?

by jhfine＠idirect.com

aaaaa >Ethan Dicks wrote: > I am attempting to back up some floppies from a project I did a few years ago. > The sets of 3.5" 1.44Mb IBM floppies have been stored in a box, in a cool and > dry room. Out of one set of 12 and one set of 15 disks, I have four disks > that have read errors that DOS won't get past, bad sectors and the like. Jerome Fine replies: You don't mention if the bad sectors are in the data or the file structure. Also, if in the data, would a partial recovery of the file be acceptable? Also, out of 2880 blocks for each 3.5" 1.44 MByte floppy, about how many sectors (blocks) are bad? While I can't help much with hardware recovery techniques, I can guarantee that you can use RT-11 to at least write (copy) each diskette onto a second copy with only the bad sectors not copied across. If all the bad sectors are in the data files, you will at least recover as much of the file as possible. Sometimes in RT-11, blocks that are mostly bad can be encouraged to be duplicated by repeated attempts. The copy utilities (PIP or DUP) have a switch to repeat the read until it completely fails OR to IGNORE failures and continue. I don't remember if a DEVICE copy has that feature, but if you say you are willing to try RT-11, I can help guide you through the process. What OS on what hardware will you read the 3.5" floppy. If it is a PC under W95 (I use it only to do e-mail - not by choice), there are very good tools to help. Sincerely yours, Jerome Fine RT-11/TSX-PLUS User/Addict

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

This must be something different from what we had at the beginning, as the constraints were for production processors commercially available in 1982-1983 and in either the Z-80 or 6502 architecture families. The reason for this is obvious. It has got to be possible to run the code in a real device in the "here and now" timeframe. Otherwise one could simply say well, "I wrote this code for the XYZ at 24.576 GHz and the whole program requires only one instruction." Further constraint should be that the author must own a running system capable of running the subject software on it in the native processor. This system must consist of components commercially available during or before the subject time period, i.e. 1983. Thirdly, it should be proven by replication (successful execution of the submitted code set on another computer not necessarily owned by the author of the submitted software) that this fete is achievable with the code set submitted. A simulator or even some fancier assemblers can be used to indicate the execution time. It's not desirable to include processors which don't exist yet in any comparison purported to be a timing comparison between Z-80 and 6502. That doesn't mean you can't look at whatever else someone might submit for general inspection and interest, but we do want to have a well-defined goal. -----Original Message----- From: Sellam Ismail <dastar(a)ncal.verio.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 5:27 PM Subject: Re: z80 timing... 6502 timing >On Sat, 17 Apr 1999, Tony Duell wrote: > >> > Contest open for any CPU anyone would care to write code for. >> >> Including one that I've designed? In which case, how general-purpose does >> it have to be? I have half an idea to make a state machine that does >> binary -> roman conversions, but not anything else. I suspect I could get >> it rather fast, though. > >Sure, why not! That would be great. > >> (Yes, that's cheating. I know it's cheating. But it's not specifically >> disallowed by the above). > >I don't think anyone should have to be handicapped. Of course, you'll >have to demonstrate that it actually work, although I have no doubt you >can and will :) > >Sellam Alternate e-mail: dastar(a)siconic.com >--------------------------------------------------------------------------- --- >Don't rub the lamp if you don't want the genie to come out. > > Coming this October 2-3: Vintage Computer Festival 3.0! > See http://www.vintage.org/vcf for details! > [Last web site update: 04/03/99] >

26 years, 10 months

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Dumb OS question

by jolminkh＠nsw.bigpond.net.au

I recently found an ancient copy of QNX, which seems to be a light unix like OS. Looking on the WEB, I found that current versions are still around, but marketed as a "Real Time" OS. The 80's documentation I have says nothing about real time. My dumb question: What is a real time operating system? Hans Olminkhof

26 years, 10 months

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Amiga 2000HD Hard disk

by ethan_dicks＠yahoo.com

--- LordTyran <a2k(a)one.net> wrote: > Beats me. I just said screw it and reformatted the old drive. Boot from an install floppy and check the device numbers with showconfig. > I know that it autoboots, as I've done it many many times with this card OK... that's a good start. There are ways to check the driver name, but not with the supplied tools. > .. And just checking up on my emails with my hand VT100 > terminal and 14.4 modem :) Ugh. It's been a long time since I've had to do that. > P.S. Do you have CIAs that you would like to sell? I'd be interested in > getting my dead 500 working again.. Not really. I have some A500 boards here, but I'd have to pull chips from them to get chips. Are the usual sources dried up? I haven't had to buy any Amiga chips in a while. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 10 months

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NAB Vegas (on topic)

by jpl15＠netcom.com

Any classiccmpers attending the NAB show in Vegas next week? I will be there Tuesday all day... about as much as I can stand of trade shows... even ones specific to my career. :) If so, drop me private e-mail if you would like to get together, or just meet somewhere and say 'hi' on Tues the 20th. [Okay so it's more on-topic than Evolutionary Civic Nomenclature..] Cheers John PS: SoCal TRW Swap, Brunch, and 1st Quarterly Compucrawl coming up on Saturday, the 27th... watch the List or e-mail me for details.

26 years, 10 months

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Amiga 2000HD Hard disk

by ethan_dicks＠yahoo.com

--- LordTyran <a2k(a)one.net> wrote: > Hmm... I'll take the 68k if you can get me an even and odd CIA :) > > Well, I know about HDToolbox, but there's one problem. > > When I try to run HDToolbox, it always says "Driver not installed" in the > box that is supposed to contain drive information. What kind of SCSI card do you have? HDToolbox can be invoked with a parameter (Tooltype from Workbench, CLI parameter from CLI) specifying the SCSI-driver's name. If your controller is not autobooting, you may need to build a special boot floppy with the driver in the Expansion drawer and a BindDrivers to load it into RAM. The default driver name for HDToolbox is scsi.device. If your card does not use that as a driver name, the software won't go looking for it. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 10 months

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All this OT stuff...

by kyrrin＠bluefeathertech.com

NOTE: This will be my ONLY message to the list on this subject. I will not reply except via private E-mail. Ya know, when I first joined CLASSICCMP, I joined because I felt it would be a good resource to aid in my work with DEC systems (notably VAXen and PDP), and a meeting place for those who still knew which end of a soldering pencil to use. So far, it has proven to be both, and I've been pretty happy with it. I couldn't care less about the occasional flame war. Such things are inevitable. I'll simply filter it and get on with life. HOWEVER -- Am I the only one getting -really- fed up with all the 'OT:' and 'Re: OT' subject lines and off-topic messages? If a subject is off-topic for the list, then it is off-topic for the list and should, IMO, be taken to private E-mail. Just because you mark it OT does not, in my view, make it OK to clutter the list with it. I've installed a filter at my end that should dump most, if not all, messages with OT: in the subject line. However, the point remains that I should not have had to do so in the first place. Please take OT's elsewhere. Ok? Thanks! -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner and head honcho, Blue Feather Technologies http://www.bluefeathertech.com Amateur Radio:(WD6EOS) E-mail: kyrrin(a)bluefeathertech.com SysOp: The Dragon's Cave (Fido 1:343/272, 253-639-9905) "Our science can only describe an object, event, or living thing in our own human terms. It cannot, in any way, define any of them..."

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

Let's not start throwing up our respective hands in disgust! Nothing's been attempted yet. In fact, nothing's been suggested yet except a couple of things which at first inspection didn't seem like they'd work. Now, Hans Franke suggested something like a KIM-1. There's no reason one couldn't code for something LIKE a KIM-1, even the guys working the Z-80 side, but it's not convenient programming a 6532 or whatever those ROM-I/O-Timer things were, or even a 6522 for simple I/O if that's what's needed. I suggested a published algorithm which solves a published problem or something close to that. There haven't been many suggestions made yet, so it's inappropriate to choose. If one wants the hardware, it should be the SAME hardware throughout the exercise, though. That's why I was suggesting a simulator. All that's really needed is a run to see if it actually will execute and end up with the desired result when code is submitted to the hardware. A simulator would be adequate so long as it was trusted to give honest timing results. That way, nobody would have to risk burning his fingers. Dick -----Original Message----- From: Sellam Ismail <dastar(a)ncal.verio.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 3:01 PM Subject: Re: z80 timing... 6502 timing >On Sat, 17 Apr 1999, Richard Erlacher wrote: > >> Do we really want to build hardware for the sake of this comparison? >> Writing a bare-bones simulator would be straightforward enough. It's really >> just a big switch statement. The beauty is that you can include/exclude >> undocumented features as you see fit. The gotcha is that it's easy to go >> down a road which has no relevance to reality, i.e. if the processor doesn't >> work like that, even though it should, then simulating it like that is not >> valid. > >Ok, let's first assemble a committee to decide all these issues. We'll >have to start with a Statement of Work. Perhaps we should put out an RFP >first to select the person or group who should develop the SoW. Of course >we'll have to pull together a comittee to draft the RFP. Once that's all >done, then we must put together an administrative committee. We'll have >to vote in a President, Vice President and Secretary. Perhaps we should >incorporate as well. Let's choose the state of Delaware, since that seems >to be the quickest route. > >Fucken-A people! Is this supposed to be a simple coding challenge, or a >competition to see how much work we can create around the same? At the >rate you all are going, it will be a year before we can even decide what >it is we'll be coding! > >Sellam Alternate e-mail: dastar(a)siconic.com >--------------------------------------------------------------------------- --- >Don't rub the lamp if you don't want the genie to come out. > > Coming this October 2-3: Vintage Computer Festival 3.0! > See http://www.vintage.org/vcf for details! > [Last web site update: 04/03/99] >

26 years, 10 months

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Coding competitions

by cmcmanis＠mcmanis.com

Are a waste of time on separate architectures. We've basically seen the benchmark discussion recreated in what is a somewhat classic vein. If there were really old Usenet archives around you could search comp.sys.arch for the keyword Dhrystone and get this same conversation all over again. However, there are fun competitions, and I'll toss one out for y'all: Compute as many digits of pi as you can on a CARDIAC. Lowest score wins, points scored as follows: +1 for every memory location used. (0 and 99 don't count) +4 for every space on the output card that doesn't contain part of the answer. A card has 24 slots so submitting no program at all will score 96. --Chuck

26 years, 10 months

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Amiga 2000HD Hard disk

by ethan_dicks＠yahoo.com

--- LordTyran <a2k(a)one.net> wrote: > Hello, a while ago I got a semi-functioning Amiga 2000HD... after > tinkering with it for a bit, the accelerator crashed the machine every few > minutes, the install was screwed, etc. So, After finding the 68k chip bad, > I pulled one from my dead A500 I can sell you another 68K chip, cheap. I have several. > ...I now how a functioning system... except the HD with a screwed > up install. I want to use a 105-meg SCSI drive that I rescued from a Mac > at school. I have an complete set of install disks for the 2.1 OS but for > some reason it can't detect my drive when I try to format it. None of the > hard disk programs detect it. (When I boot from the install disk with the > old HD installed, it appears as an icon on the Workbench, but when I boot > with my 105 meg drive installed, no other icons appear. There is a prep phase before which you will get no icons. Amigas use a thing called the RDB which contains, among other things, the partition table. Look for HDToolbox in (I think) the Tools drawer of one of the bootable OS2.1 floppies. You can low-level format the drive, check for bad blocks, add new blocks by number, test the surface (read only) and write out a partition table. OS2.1 might insist on a couple of partitions, WB_2.x and WORK. My old A3000 came with some interesting disks for Workbench 2.01 and 2.02; there's some extra stuff that is helpful for auto-partitioning disks with script files. You will want at least 15Mb for WB_2.x All it has to hold is the OS itself (5 880Kb floppies) and anything you add of that sort (drivers, fonts, etc). All the real stuff should go into WORK. Good Luck, -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 10 months

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x86, x86 everywhere, but... (was OT: Re: Time to declare State

by ethan_dicks＠yahoo.com

--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote: > > What? Valueless? Not at all. Get an XT or an 286, give it a 10 or 20 meg > > HD, throw a 10BaseT network card in it (I have those coming out of my > > ears, thanks to all my friends!), install Minix on it, and make it a node > > on your friendly house-hold network. Or forget the network card and use a > > Oh, sure. _I_ don't think they're valueless either. On the desk in front > of me is an XT (original IBM5160). It runs my EPROM programmer, my GAL > programmer, my cable tester, etc. It reads PERQ disks. It is certainly > useful to me. I use a Commodore Colt for the same thing - 8088, soft turbo mode, 3 8-bit slots, supports 3.5" 720K floppies, built-in XT-IDE (I've got a WD93028X on it). I have my ROM programmer on it, an 8003 Ethernet card and I move files to and from it with Kermit over TCP/IP. This does not mean that it's all I would ever want... I enjoy the web, and it's not suitable for more than Lynx, but I do use it and I wouldn't retire it easily. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 10 months

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Burroughs 205 anyone??? (fwd)

by siconic＠jasmine.psyber.com

Can anyone help this guy out? Please reply to the original sender. Reply-to: B9BUILDER(a)aol.com ---------- Forwarded message ---------- Date: Fri, 16 Apr 1999 23:37:53 EDT From: B9BUILDER(a)aol.com Subject: Help!!!! Hello My name is Doug Hines, I am trying to build a set from the tv show lost in space. I have been told by several people that the main flight deck had several burroughs 205 computers. I am trying to find someone that might have that model for sale. Any help would be super. Thank's. Doug Hines Sellam Alternate e-mail: dastar(a)verio.com ------------------------------------------------------------------------------- Puttin' the smack down on the man! Coming in 1999: Vintage Computer Festival 3.0! See http://www.vintage.org/vcf for details [Last web site update: 04/03/99]

26 years, 10 months

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OT Was z80 timing... 6502 timing

by edick＠idcomm.com

I was trying to figure out whether it was politically correct to correct someone else's spelling in this forum. I had the impression that there was no orthographic police here. There certainly is a lot of error in that department. Even my rented fingers don't spell any worse than the average here. Now . . . What do you mean your money's on TONY? Which Tony? Dick -----Original Message----- From: jax <jax(a)tvec.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 10:49 AM Subject: Re: OT Was z80 timing... 6502 timing > >>Ooh! A machine code competition. I'm in! I'll do the 6502 and whoop >>EVERYONE'S ass! >> > > >Wait just a minute..... > >Since we have been discussing various "ethnic" pronunciations, I am >compelled to point out that this statement may be interpeted differently >than intended. > >As a born\bred survivor of the land of redneck, pickup truck, and chewing >tobacco, I assert that a "whoop" is a loud yelling type of activity. The >execution of which on someone's posterior will bring a certain confusion to >your enemy ( he will think you are a fruit ), but will not render him >defeated. > >I laughed so hard at this mental image it made me hurt. :) > >Try "whup" next time, as in "opening a can of whup-ass". > >My 2 centavos from the Republic of Texas. > >BTW, my money's on Tony. > > > jax(a)tvec.net >

26 years, 10 months

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unsubscribing/resubscribing

by roblwill＠usaor.net

Can someone please tell me how to unsubscribe/resubscribe? I currently have a dedicated classiccmp email address, and would like to switch the list over to it, but I forget how. ThAnX, -- -Jason Willgruber (roblwill(a)usaor.net) ICQ#: 1730318 <http://members.tripod.com/general_1>

26 years, 10 months

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FM, MFM, and GCR channel codes (was Re: stepping machanism of Apple Disk ][ drive)

by mark_k＠iname.com

On 10 Apr 1999 Richard Erlacher wrote: >YES! and that's exactly why the pulse overlap was correctable with >write-precompensation at least in hard disks at 10x the data rate. In >general the amplitude of the pulses was sufficient to be detected by the >usual circuitry, but because the timing was quite far off due to the peak >shift introduced by the summing effect of the head/media combination. >Precompensation, which was not needed for FM, was between 188 and 125 nsec, >depending on the drives in use. On the older drives, 188 was pretty common. >The "bit-shift" was mitigated somewhat by the reduction of write-current on >the inner tracks. Can someone explain exactly what precompensation is? I remember reading about this in the Amiga hardware manual; in the ADKCON register there are two bits which set the precompensation (none, 140ns, 280ns or 560ns), and also one that selects GCR precompensation or MFM precompensation. Note that the encoding method is implemented completely in software, so you are not limited to MFM and GCR. (There's also a control to set the data rate, 2us or 4us per bit cell. 2us is used for MFM, apparently for GCR 4us is necessary.) -- Mark

26 years, 10 months

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z80 timing... 6502 timing

by allisonp＠world.std.com

<What were the Z80 instructions? I'd like to test them on a SBC and documen <them for the future. <Thanks, <-Dave Found this on my disk. Allison ***************************************************************** Undocumented Z80 Instructions (apply only to Z80) The Z80 IX/IY operators are missing (byte ops) mnemonic: IN ,(C) OP code: 0EDh,070h Description: Same as IN A,(C) except the A register isn't changed (flags are set as if it was changed). NOTES: This instruction can be used to test and discard the value of a port without destroying any registers. mnemonic: SLAS B OP code: 0CBh,030h Description: Shift Left Arithmetic Special B. Same as SLA B except bit 0 of B is set instead of cleared. mnemonic: SLAS C OP code: 0CBh,031h Description: Shift Left Arithmetic Special C. Same as SLA C except bit 0 of C is set instead of cleared. mnemonic: SLAS D OP code: 0CBh,032h Description: Shift Left Arithmetic Special D. Same as SLA D except bit 0 of D is set instead of cleared. mnemonic: SLAS E OP code: 0CBh,033h Description: Shift Left Arithmetic Special E. Same as SLA E except bit 0 of E is set instead of cleared. mnemonic: SLAS H OP code: 0CBh,034h Description: Shift Left Arithmetic Special H. Same as SLA H except bit 0 of H is set instead of cleared. mnemonic: SLAS L OP code: 0CBh,035h Description: Shift Left Arithmetic Special L. Same as SLA L except bit 0 of L is set instead of cleared. mnemonic: SLAS (HL) OP code: 0CBh,036h Description: Shift Left Arithmetic Special (HL). Same as SLA (HL) except bit 0 of (HL) is set instead of cleared. mnemonic: SLAS A OP code: 0CBh,037h Description: Shift Left Arithmetic Special A. Same as SLA A except bit 0 of A is set instead of cleared. *****************************************************************

26 years, 10 months

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FM, MFM, and GCR channel codes (was Re: stepping machanism of Apple Disk ][ drive)

by edick＠idcomm.com

Yes, . . . at least I think I can. When data is written to magnetic media, there is a maximal bit density which can be written which is a function of the head and media characteristics as well as the velocity with which the data stream passes the heads. each transition is detected (read) as a pulse of a given width and amplitude. Changes in the sense of the data are recorded by reversing the magnetic flux written on the medium. If two flux reversals are written close together, they can overlap slightly. The consequence of this overlap is that their peaks are effectively pushed apart by the summing of the adjacent flux reversals, since the two amplitudes are never zero but are simply reversed while still having a non-negative value. The pulses resulting from the recovery of these reversals in flux are added together. Since they overlap, the insignificant portion close to the crossover are nonzero, so in the sum, the rising waveform of the second pulse is subtractively combined with the falling waveform of the first. This means that neither pulse reaches its maximum amplitude but its apparent peak appears at the point on the rising waveform at which the difference between the two pulses is reached, which makes the first pulse peak earlier and the second pulse peak later. In order to compensate for this, the pulse which would logically be detected "too early" is written late, and the pulse which would be detected late is written early, and as a result, the resulting pulse train is slightly reduced in amplitude, but the peaks are detected at the proper times, which is what matters. Dick -----Original Message----- From: Mark <mark_k(a)iname.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 3:20 PM Subject: Re: FM, MFM, and GCR channel codes (was Re: stepping machanism of Apple Disk ][ drive) >On 10 Apr 1999 Richard Erlacher wrote: >>YES! and that's exactly why the pulse overlap was correctable with >>write-precompensation at least in hard disks at 10x the data rate. In >>general the amplitude of the pulses was sufficient to be detected by the >>usual circuitry, but because the timing was quite far off due to the peak >>shift introduced by the summing effect of the head/media combination. >>Precompensation, which was not needed for FM, was between 188 and 125 nsec, >>depending on the drives in use. On the older drives, 188 was pretty common. >>The "bit-shift" was mitigated somewhat by the reduction of write-current on >>the inner tracks. > >Can someone explain exactly what precompensation is? > >I remember reading about this in the Amiga hardware manual; in the ADKCON >register there are two bits which set the precompensation (none, 140ns, 280ns >or 560ns), and also one that selects GCR precompensation or MFM >precompensation. Note that the encoding method is implemented completely in >software, so you are not limited to MFM and GCR. > >(There's also a control to set the data rate, 2us or 4us per bit cell. 2us is >used for MFM, apparently for GCR 4us is necessary.) > > > >-- Mark >

26 years, 10 months

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z80 timing... 6502 timing

by allisonp＠world.std.com

The 6502 series ahd all sorts of undocumented opcodes and they tended to change with later versions. <THe 65xx stuff is quite known, but what has been new to my ears are the <8085 'hidden' operations. Those were more useful as the 8085 had some rather open holes in the instruction set. The z80 also had a raft of them all commonly supported though officially unofficial. and none were compatable with the 8085 hidden ops (in either direction). Allison

26 years, 10 months

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How to read recalcitrant floppies?

by cisin＠xenosoft.com

On Sat, 17 Apr 1999, Ethan Dicks wrote: > . . . > that have read errors that DOS won't get past, bad sectors and the like. For most situations it surely wouldn't matter. But for diskette repair, it would actually help to be more specific on the exact error messages. For example, with a "Parity error", or even "Data error during read", then it may be possible to easily recover a partially correct sector content. But NOT with a "sector not found" error, which can only be fixed by patching up the sector headers. > Are there any tools to go divining on DOS floppies that work better than > an endless succession of "R"etries? It's an all or nothing prospect; the > first disk has the install file, the remaning disks have a chopped monolithic > data file. If one disk can't be read, the whole set is fundamentally useless. > Thanks for any suggestions. The Central Point "Option Board", running the TE (Track Editor) program can be quite useful for such repairs. It will let you view what it thinks are the data bits, and/or what it thinks are the clock bits. By fiddling with them and then writing it back, you may be able to repair the damage, even damage to the sector headers! Another similar tool is Trakcess running on a TRS-80 model 3. Sometimes R-etrying enough times can actually work. If you write a short routine to read the suspect sector with INT13 in a loop, you might eventually get a successful read. -- Fred Cisin cisin(a)xenosoft.com XenoSoft http://www.xenosoft.com 2210 Sixth St. (510) 644-9366 Berkeley, CA 94710-2219

26 years, 10 months

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Apple HAL XEBEC controller

by pete＠dunnington.u-net.com

One of today's acquisitions is a small card for an Apple ][ (or Apple ///), labelled "APPLE 2/3 XEBEC INTERFACE REV 1". I happen to have a couple of old Xebec ST412 winchester controllers, so I'd like to try this out. Can anyone tell me the pinout of the 26-pin header at the end of the card? Pins 3,7,11,15,17,19,21,23,25 are grounded, the other seventeen seem to be signal lines. Pins 1,5,9,13,20 are high impedance; the other even-numbered pins are terminated by a 220/330R resistor pack. Does it need any other software (like a formatting disk)? The on-board 4K EPROM contains only the strings "(C) HAL COMPUTERS LTD 1983", "A/XHAL SHARED RESOURCE WINCHESTER SYSTEM", "NOT CONNECTED", and "SRS ERROR", so I guess there would have been a floppy with it, originally. -- Pete Peter Turnbull Dept. of Computer Science University of York

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

I've been told, can't prove it, though, that the NEC version of the Z-80 didn't have that "bug" (short for undocumented feature, as in "one man's feature is another man's creature") that in certain instances the flags were incorrectly set by a block load instruction or some such. It's little things like that that can throw folks off. That, actually, is why I favor a simulator. I've just never seen a proper simulator for either processor in an "open" environment, i.e. where only the processor is simulated. That makes it entirely hardware independent. Some folks would believe, however, that since it's not possible to build a system that's hardware independent, it's not valid to simulate one. Do we really want to build hardware for the sake of this comparison? Writing a bare-bones simulator would be straightforward enough. It's really just a big switch statement. The beauty is that you can include/exclude undocumented features as you see fit. The gotcha is that it's easy to go down a road which has no relevance to reality, i.e. if the processor doesn't work like that, even though it should, then simulating it like that is not valid. Dick -----Original Message----- From: Allison J Parent <allisonp(a)world.std.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 9:20 AM Subject: Re: z80 timing... 6502 timing ><65C02, because it was buillt in several conflicting versions. What about ><the Z-80 core? Whose? Which one? Speed, of course, should be "limited" t ><whatever was available in 1982. That certainly includes the Synertek (MOS > >In 1982 all of the z80s in the market had the same hidden features >including the IX/IY 8bit ops. I know of no z80 that didn't have them. >Not all of them were available to the 6mhz spec though many could be >pushed. Also allowed is the 8085 (available as a 5-6mhz part then). Again >all of the 8085s had the extra unsupported instructions as they were deem >important! > >Allison >

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

about those undocumented opcodes . . . I didn't pursue what happened to them in the UMC, VLSI, SYNERTEK, Mitsubishi, or WDC (WSI) parts. I heard rumors, but wasn't concerned about it then. After 1982 I only used the ROCKWELL CMOS parts. Rockwell took care of them by getting rid of them. Of course they expanded the instruction set as did several others. Dick -----Original Message----- From: Allison J Parent <allisonp(a)world.std.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 1:42 PM Subject: Re: z80 timing... 6502 timing >The 6502 series had all sorts of undocumented opcodes and they tended to >change with later versions. Rockwell made a specific point about the undocumented opcodes in their version, in that all the unimplemented opcode values in their CMOS parts were NO-OP's. ><THe 65xx stuff is quite known, but what has been new to my ears are the ><8085 'hidden' operations. > >Those were more useful as the 8085 had some rather open holes in the >instruction set. The z80 also had a raft of them all commonly supported >though officially unofficial. and none were compatable with the 8085 hidden >ops (in either direction). > >Allison >

26 years, 10 months

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z80 timing... 6502 timing

by allisonp＠world.std.com

<The one I routinely hear about the Z-80 is one which places the odd parity <of the bytes (or maybe the lsb's of the bytes) in a block moved with an LDI <or INIR instruction into the carry or some such. This instruction is <supposed to leave carry unaffected, but doesn't. If it did it never happens to me and ouls severly break code. The block moves and compares are widely used in z80s. The only flag affected is the P/V and that is documented BC-1=0. The z80 does have a difference from the 8080 for some operation regarding the parity/overflow flag.

26 years, 10 months

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z80 timing... 6502 timing

by allisonp＠world.std.com

<I've been told, can't prove it, though, that the NEC version of the Z-80 <didn't have that "bug" (short for undocumented feature, as in "one man's <feature is another man's creature") that in certain instances the flags wer Did not have that "bug". I don't know that any z80 had it. It was exact. What was missing was a odd address bus burp during t3-t4 transistion. If your design compensated for it the NEC part didn't hurt you and if you didn't It might help. Now the z180 between zilog and hitachi had bugs. The Z280 was buggy too. Allison

26 years, 10 months

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z80 timing... 6502 timing

by allisonp＠world.std.com

<b) unsupported OPCs in the 8085 ? Did I miss them ? I did 2 years of <8085 development projects, and never heared of (also of course never <used) - can you tell what they where alike ? Yes, They are somewhat handy. 08h DSB double subtract HL-BC->HL 10h SHRL shift right HL Shift HL pair right, MSB is copied 10001000:00000010 becomes 11000100:00000001 18h RDEL Rotate DE right through carry, handy 16bit rotate. SLDE (intel used this neumonic) 28h LRI h,D8 load relative pointer immediate The value of HL is added with the immediate placed in the DE pair. 38h LRI SP,D8 similar to the previous, good for SP relative ops. D9h SHLX Store HL at DE an indexed 16bit store. EDh LHLX Load HL from where DE points. 16 bit indexed load. This is from memory... so if there are errors let me know, I'll dig out the docs. I do remember that NEC up to at least '85 actively supported these as they were in the intel, OKI and AMD designs. Allison

26 years, 10 months

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*.cam files

by roblwill＠usaor.net

Thanks! I should have the pictures up and my web page updated by the end of the week! -- -Jason Willgruber (roblwill(a)usaor.net) ICQ#: 1730318 <http://members.tripod.com/general_1> -----Original Message----- From: Michael Passer <mwp(a)acm.org> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 6:00 AM Subject: Re: *.cam files >If those files are from a Casio QV digital camera, a program to convert >them to the JPG format is available at > >ftp://ftp.itojun.org/pub/digi-cam/QV10/ > >There are both Unix and Windows versions available. I tested the >Windows version and it's straightforward and works. > >Hope this helps! > >--Michael Passer >mwp(a)acm.org > > >----- Original Message ----- >From: Jason Willgruber <roblwill(a)usaor.net> >To: Discussion re-collecting of classic computers ><classiccmp(a)u.washington.edu> >Sent: Saturday, April 17, 1999 12:33 AM >Subject: *.cam files > > >> Hi! >> >> I was just given some *.cam files. They're supposed to be image files >of a >> computer to put on my webpage (classic computer section). They were >taken >> with a digital camera, and downloaded to a PC. My question is: how >in the >> heck do I view them?? Anyone have any idea? >> -- >> -Jason Willgruber >> (roblwill(a)usaor.net) >> ICQ#: 1730318 >> <http://members.tripod.com/general_1> >> >> > >

26 years, 10 months

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x86, x86 everywhere, but... (was OT: Re: Time to declare State of MA)

by yakowenk＠cs.unc.edu

I am slowly coming to accept that my value set was molded when certain things were scarce, and no longer are. I would have been thrilled to get any kind of computer when I was in high school. So it is hard for me to imagine people willing to throw away _any_ computer. But now I am starting to see that XT's and 286's are like paper cups. Not only do they tend to work less well as they age (they eventually break and lack support from their manufacturers), but they are really next to valueless in terms of replacement cost. Even if getting a computer to somebody who is destitute, the time of the compu-geek who sets it up is worth more than a newer faster machine would be. The only difference between the old x86 machines and paper cups is quantity: there are fewer paper cups. Bill. (I'm not advocating a throw-away culture, BTW. Just noting the economics of the situation. I wish we could convince people to put in the effort to use and learn from the old machines rather than continuously filling up landfills with them just to make more. But I'm still a long way from getting the rest of the world to see things my way.) (Okay, so that's another difference between XTs and paper cups: paper cups are more landfill-friendly.) On 15 Apr 1999, Mike Ford <mikeford(a)netwiz.net> wrote: ] The Goodwill near me just got 600 computers from Pacific Bell, all 486 and ] older, most in pretty good shape. The result is that a LOT more only ] slightly wanky 486 boxes are getting tossed in the scrappers bin. Goodwill ] won't take a 386, or if it gets in the product stream it goes either to the ] scrapper or the huge AS-IS morning auction of bins of stuff only loosely ] sorted by category. ] ] However painfull you may find it personally, it only takes a TINY bit wrong ] to make an old computer have negative value except as scrap or parts.

26 years, 10 months

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OT: Welfare state morality

by allisonp＠world.std.com

<is simply that these computers aren't new enough. They can be used for <anything that a new one can be used for, but they won't read the newest MS BZZT. i'm running a PS/250z with a scanner and I can and do. <Word files. Microsoft made sure of that. Believe it or not, people can be Simple dont use word, it's virus prone. <very picky about such things. Also, there is the issue that the computer <will never be used, or will get thrown away the next day, whatever. The <point is that there is no justification for the trouble it takes to <distribute computers to individuals. If these individuals want to get a <computer, fine. I have found dozens of computers in garbage cans, I'm sure <they can do no worse. There is a lot of truth to that. I think it's more the matter of where Max is a decent 386 is trash fodder but in may parts of this country (USA!) that would be a windfall. After a day of trying to make billies OS and code work, killing a gutted clone sounds like a great release of stress. ;) Allison

26 years, 10 months

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How to read recalcitrant floppies?

by ethan_dicks＠yahoo.com

I am attempting to back up some floppies from a project I did a few years ago. The sets of 3.5" 1.44Mb IBM floppies have been stored in a box, in a cool and dry room. Out of one set of 12 and one set of 15 disks, I have four disks that have read errors that DOS won't get past, bad sectors and the like. I know that circa 1993, these disks were good. They were written once, mailed to me, loaded once and put away. I would like to preserve the data because it has some small historic significance. It's not earth-shattering if the data is gone forever, but those of us who play adventure games would lose a little link to the past. I do not belive that the client still has copies of this original data, so that's not an option. The project eventually made it to market, so it's not a "lost" game or anything; but these disks do represent a work in progress with some interesting bugs. Are there any tools to go divining on DOS floppies that work better than an endless succession of "R"etries? It's an all or nothing prospect; the first disk has the install file, the remaning disks have a chopped monolithic data file. If one disk can't be read, the whole set is fundamentally useless. Thanks for any suggestions. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

As I recall, all the undocumented operations have the two ls bits set. Is that correct? Maybe I should add them to my assembler/debugger. The one I routinely hear about the Z-80 is one which places the odd parity of the bytes (or maybe the lsb's of the bytes) in a block moved with an LDIR or INIR instruction into the carry or some such. This instruction is supposed to leave carry unaffected, but doesn't. Dick -----Original Message----- From: Hans Franke <Hans.Franke(a)mch20.sbs.de> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 10:15 AM Subject: Re: z80 timing... 6502 timing >> Were you aware of the neat little opcodes that were built into the 6502? I >> don't have my list of them any more, but back in the KIM days, there were >> several lists in circulation. As I recall, one of them was a double load, >> i.e it loaded a value into both a register and the accumulator. I believe >> another loaded a register and pushed the value on the stack at the same >> time. Esoteric, for sure, but you never know . . . > >Like SHIFT&OR (0F,1F,1B,...), ROL&AND (2F,3F,3B,...), LSR&XOR ($F,5F,5B,...), >ROR&ADD (6F,7F,7B,...) etc ... most are realy exotic and save only a second >instruction, but some could have been a big help, if they had been official >(like AND A,X and STORE, without changing A or X - saving up to 4 instructions, >or LOAD A&X, or AND MEM&X/MEM&Y). Some are more or less useles, like the STOP >(halts execution, only reset will wake up the CPU) or just longer NOPs (two and >tree cycles). > >THe 65xx stuff is quite known, but what has been new to my ears are the >8085 'hidden' operations. > >Gruss >H. > >-- >Stimm gegen SPAM: http://www.politik-digital.de/spam/de/ >Vote against SPAM: http://www.politik-digital.de/spam/en/ >Votez contre le SPAM: http://www.politik-digital.de/spam/fr/ >Ich denke, also bin ich, also gut >HRK

26 years, 10 months

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Apple HAL XEBEC controller

by edick＠idcomm.com

Xebec made a number of "specialized" bridge controllers, which fit between the host adapter, which is what you've described, in this case possibly intended to go to a compatible version of their 14xx-series controllers which, in turn, provides a SCSI interface to an ST506 drive, which you apparently have on hand. It is likely that the 26-pin connector is to the Apple II version of SCSI which was put out back then on a 25-pin DB-25 connector. I recently got a drive with a Xebec label on its enclosure, having bought it for the enclosure, and found the drive had an integrated adapter on it which was terninated in a DC-37 connector, not unlike what was on the early Bernoulli Boxes from IOMEGA. I didn't investigate the pinout or anything, naturally, since I don't care about small drives like this. There's probably a similar version for this card's interface as well. Dick -----Original Message----- From: Pete Turnbull <pete(a)dunnington.u-net.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 9:45 AM Subject: Apple HAL XEBEC controller >One of today's acquisitions is a small card for an Apple ][ (or Apple ///), >labelled "APPLE 2/3 XEBEC INTERFACE REV 1". > >I happen to have a couple of old Xebec ST412 winchester controllers, so I'd >like to try this out. > >Can anyone tell me the pinout of the 26-pin header at the end of the card? > Pins 3,7,11,15,17,19,21,23,25 are grounded, the other seventeen seem to be >signal lines. Pins 1,5,9,13,20 are high impedance; the other even-numbered >pins are terminated by a 220/330R resistor pack. > >Does it need any other software (like a formatting disk)? The on-board 4K >EPROM contains only the strings "(C) HAL COMPUTERS LTD 1983", "A/XHAL >SHARED RESOURCE WINCHESTER SYSTEM", "NOT CONNECTED", and "SRS ERROR", so I >guess there would have been a floppy with it, originally. > >-- > >Pete Peter Turnbull > Dept. of Computer Science > University of York

26 years, 10 months

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Several things

by yakowenk＠cs.unc.edu

On 9 Apr 1999, ard(a)p850ug1.demon.co.uk (Tony Duell) wrote: ... ] A ROM _is_ combinatorial logic. I don't want to get into a silly argument ] over this, but I have great difficulty finding a conceptual difference ] between a combinatorial circuit built from a pile of AND, OR and NOT ] gates and the same circuit built (albeit using a lot more transistors) in ] a ROM. To claim that a CPU using a ROM is microcoded but one with ] _identical_ internal states using simple gates as the feedback logic ] round the sequencer flip-flops is not is a very strange way of thinking ] about things. Request accepted; silly argument follows. (Oh, you said "don't"? Oh well, too late.) Do you mean to say that _all_ computers are microcoded? After all, the control logic can always be modelled by some number of state FFs and a large-enough ROM, couldn't it? Or is your claim that there is no such thing as microcoding? That strikes me as far-fetched as well. The difference is that a ROM is easily replaceable; slap in another ROM or EPROM with different microcode burned in, and you've got an entirely different machine on your hands. Maybe to you it is just as easy to redesign some section of the circuit board, etch a new one, pull the newly required chips from your very-deep storage bin, and Bingo! you're done. For most of us, I suspect that sounds like quite a lot of effort. I don't think anybody ever claimed that microcoded machines could do things that non-microcoded machine could not, or vice-versa. It is a matter of convenience. And maybe there is some added comfort level for software geeks, using a (micro)program to control everything, and being able to alter it just like any other software (or firmware). I guess it is exactly the added (and admittedly wasted in any fixed design) transistors, just sitting there unused, waiting to be assigned work, that makes microcoding attractive - it is easier to adjust precisely because you don't have to muck around with how many transistors are in there, or worry about board-space/power-consumption/fanout/etc/etc that you might have to worry about if you wanted to adjust some hard- wired discrete logic. Bill. (Gee, that didn't turn out to be nearly as silly as I had expected.)

26 years, 10 months

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Signal detection

by max82＠surfree.com

Hi, Could anyone tell me how a radio detects signals vs. static? There is a little gauge on my radio that moves depending on the amount of noise vs. signal. I would guess that the digitally tuned radios that skip over the frequencies that are pure static work in the same way. What is this way? --Max Eskin (max82(a)surfree.com) http://scivault.hypermart.net: Ignorance is Impotence - Knowledge is Power

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

Were you aware of the neat little opcodes that were built into the 6502? I don't have my list of them any more, but back in the KIM days, there were several lists in circulation. As I recall, one of them was a double load, i.e it loaded a value into both a register and the accumulator. I believe another loaded a register and pushed the value on the stack at the same time. Esoteric, for sure, but you never know . . . Dick -----Original Message----- From: Hans Franke <Hans.Franke(a)mch20.sbs.de> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 9:27 AM Subject: Re: z80 timing... 6502 timing >> <65C02, because it was buillt in several conflicting versions. What about >> <the Z-80 core? Whose? Which one? Speed, of course, should be "limited" t >> <whatever was available in 1982. That certainly includes the Synertek (MOS > >> In 1982 all of the z80s in the market had the same hidden features >> including the IX/IY 8bit ops. I know of no z80 that didn't have them. >> Not all of them were available to the 6mhz spec though many could be >> pushed. Also allowed is the 8085 (available as a 5-6mhz part then). Again >> all of the 8085s had the extra unsupported instructions as they were deem >> important! > >a) The speed (of a particular CPU) used is not important for this, since >(I assume) we all can handle the transformation - the goal is still the >factor to use to judge the relative power. >b) unsupported OPCs in the 8085 ? Did I miss them ? I did 2 years of >8085 development projects, and never heared of (also of course never >used) - can you tell what they where alike ? > >Gruss >H. > >-- >Stimm gegen SPAM: http://www.politik-digital.de/spam/de/ >Vote against SPAM: http://www.politik-digital.de/spam/en/ >Votez contre le SPAM: http://www.politik-digital.de/spam/fr/ >Ich denke, also bin ich, also gut >HRK

26 years, 10 months

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OT: City Names

by gareth.knight2＠which.net

William Donzelli >If people want to send _way_ off topic stuff to this list, my requests are >articles about ice fishing, reprints of old Home & Garden magazines, or >hardcore pornography. For the right price I can get you hardcore porn of women ice fishing with copies of Home & Garden. ;) -- Gareth Knight Amiga Interactive Guide | ICQ No. 24185856 http://welcome.to/aig | "Shine on your star"

26 years, 10 months

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Power Frequency

by allisonp＠world.std.com

<I think you are spot on there, I am led to believe the 60hz decision in th <US and some other countries was made to facilitate the use of the <(relatively) precise mains frequency for clocks and other timing functions <This is also possible, even for motor driven clocks, with 50hz mains simpl <by careful motor design. Though it may have been less simple when the <decision was made. makes no difference save for one item... <equivalent to the mains frequency. This reduces/eliminates mains hum <strobing, though it is more of a historical problem with modern TV designs <think. No, more of a problem with OLD designs. The key item is that motors and transformers are physically smaller for same or similar VA capability with increasing frequency. there is a corner you turn as you go higher though as the iron in the course gets lossier and line radiation increses losses. So power distrubution has the 50/60 as a good bet. Note aircraft use 400nz for the compact transformers and reduced filtering in rectifiec circuits. There were also 25, 30 and 40hz systems. The NY subway at one time was 25Hz and the DEC mill prior to refurb in the 80s was 40hz (that power also lighted part of the town.) at one point in history. Allison

26 years, 10 months

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Coding chanllange (was: z80 timing... 6502 timing)

by edick＠idcomm.com

It might, in fact, be interesting to see what limitations/enhancements the hardware features of the two processor types would impose. Interleaved display memory would effect both processors' ability to use memory, etc. I'd say it will difficult enough to come up with a problems suitable for a valid exercise without such difficulties. Dick -----Original Message----- From: Hans Franke <Hans.Franke(a)mch20.sbs.de> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 7:19 AM Subject: Coding chanllange (was: z80 timing... 6502 timing) >> > >Ooh! A machine code competition. I'm in! I'll do the 6502 and whoop >> > >EVERYONE'S ass! > >> > And then you woke up. First what are the rules, 6502 or 65C02, code in Rom >> > or Ram, what is the code supposed to do? > >Good point. > >> > My vote goes for something with some graphical element so we can "see" what >> > is happening. (spinning ball, etc.) > >Nice, but already to high level. >The task should be abstract enough to run within a simple >system, lets say a SBC system with CPU, some MEM and some >of the usual I/O&Controll stuff (Ports, Serial, Timer). > >Basicly there are two types of possible challanges: >a) implements some kind of standard code in a most speedy way, or >b) build some small, but sophisticated "real world" application. > >Challenge a) would meet the basic idea we had in our discusion: >define at what ratio two processors are equivalent when executing >a real task, while b) should be sophisticated enough to give a >'boh ey' (sound of exeptional admire) effect. > >In terms of a sportive competition a) would be a compulsatory >exercise, while b) is more a voluntary (free style) exercise. > >As I stated before, for our theme a) would be more aprobiate. > >As actual tasks I would suggest >for a): a 'simple' sorting challenge >given is >- Input media >- Input structure >- input data (same data or all participants, randomly generated) >- Type of sort algo to use (what about just a bubble ? :) >- Output structur >- Output media >the score schould be made up from >Execution time (mainly for the sort, but also for I/O) >Programm length (again most points to be given on the sort itself) >Style (readability, portability, maintainability) > >for b) a thing like a small multi tasking OS could be used, >maybe for a controlling application (heating or traffic - >or what about a model railroad setup ?) or other purposes ? >(This could be chalenging, since these kind of tasks are >maybe a bit tough for our little helpers :) > >So, you're opinion ? > >> BRING IT ON, MO FO! >> Don't rub the lamp if you don't want the genie to come out. > >MO FO ? I fear, I'll have to rub the lamp. > >Gruss >H. > >-- >Stimm gegen SPAM: http://www.politik-digital.de/spam/de/ >Vote against SPAM: http://www.politik-digital.de/spam/en/ >Votez contre le SPAM: http://www.politik-digital.de/spam/fr/ >Ich denke, also bin ich, also gut >HRK

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z80 timing... 6502 timing

by KFergason＠aol.com

> <> And then you woke up. First what are the rules, 6502 or 65C02, code in Ro > <> or Ram, what is the code supposed to do? > <> > <> My vote goes for something with some graphical element so we can "see" wh > <> is happening. (spinning ball, etc.) > My vote would be to implement an algorithm. Of course, which algorithm would a gruesome discussion. Kelly

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z80 timing... 6502 timing

by allisonp＠world.std.com

<> And then you woke up. First what are the rules, 6502 or 65C02, code in Ro <> or Ram, what is the code supposed to do? <> <> My vote goes for something with some graphical element so we can "see" wh <> is happening. (spinning ball, etc.) Grpahincs favor certain cpus but then we also ahve to specify the graphic interface as it may penelize some due to interface. Personally graphics are an issue unto themselves and seperate A possible list of micros for that era, I used 1982 as a cutoff date: 8bitters: 6502 z80 8080 8085 2650 1802 SC/MP 6800 (01/02/03, 6803) 6809 8048 8049 8051 z8 uPD 7800 (7800, 7811) 16bit or larger: TI9900 808x 6800x 16032 z8000 T-11 (PDP-11 in a 40 pin dip and not the F11.) 1600 9440 uFlame Pace/8900 No doubt I've missed a few. Let the war begin. Allison

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AMPRO LITTLE BOARD, etc.

by allisonp＠world.std.com

<Golly! I wasn't aware that they actually put a SCSI controller on the <board. That must have been several rev's later than mine. My two boards Next rev. Also Ampro was one of the guns in setting the base SCSI spec around 85ish. <were the beta and first release. I put a couple of hundred of these into <the field because I liked them and they allowed pretty compact packaging. Not hard to understand. <I was propping the door to a room in the basement with a couple of 10MB <RODIME 3.5" drives which might work really well with this arrangement. I <once ran one of these with a 1"-high 3.5"Sony drive which a PC believed wa <a 1.2MB drive. Maybe I can fool the FDC drivers into doing a similar thing <That would be handy. There's no "standard" 3.5" driver for CP/M. I have 3.5" miniscribe 20mb MFM hooked to a xybec scsi bridge on a SB180(also has 5380). Looks silly since the scsi bridge is larger than the drive and the SB180s. It works because the drive is faster seek than most older mfm drives like the st225 or 251. That and it throws less heat. <>Here we go again... I DIDN'T SAY IT WAS IDE. I said it was similar in <>respect that it was a bus level interface for a controller and predates < < <No, you surely didn't say that! It doesn't use the same cable definition o <any thing like it. It just happens to use a 40-conductor cable. The reaso Doesnt saying "its not IDE" cover that? I wes refering to the idea that the bus can be a base micro IO bus (read, write, address, data, reset, misc). That at the CONCEPT level is similar to IDE. <I said I'd try modifying the firmware to talk to an IDE drive is that ther <is reason to believe that the command structure is identical although the <hardware would have to be modified to load the registers as it's done on th <16-bit -WAH controller. The fact is that the 1000-05 and the 1002-05 bridg <controller boards use the same chip (WD1010-05) as the HDD interface. <That's where the command registers are located and they'll require <programming in the same way. Since the IDE drive has, essentially, the sam <register set on it to accomplish the controller functions, and the registe <set mapped in the same way as the WD1003-WAH, it should be possible to mak <it work similarly. No yes at the concept level. At the real level the IDE has 16 bit data path like the 1003, but the 1000-5 and 1002-5 tended to ahve differences that are quite distinct. I turned them up while doing an article for TCJ. That was about applying ISA-8 WD1002-WX cards as a cheap MFM host interface. I found the -HDO board had a different address and register layout. <>Finding them can be tough. the 6mhz are more common. 8530s or 8330s are <>easier to find and offer better perfomance. <> <I'm really not that hot for it, but think it would be charming to put a se <of '-H' parts in an early AMPRO Little Board and make it work at 8MHz. Th <timing should work with 100ns DRAMs. Aside from the PROM, I doubt anythin <other than the peripherals would be affected by the speed change. Of cours There were articles for upgrading the amproLB to 8mhz. See TCJ <www.psyber.com/~tcj>. <the FDC would require a different tap from the clock divider, but everythin <else should work as is, save, perhaps the PROM. The PROM might work if th <clock switch were hacked as well. (I believe there was a little sorcery <with switching the clock speed after copying the PROM into RAM, by switchin <the preset on a counter. What I liked about this was the really sensible Why not goo whole hog if your going to switch clock speeds and do clock stuttering. That way only certain parts or the processor cycle are stretched and the rest can run full bore. <packaging you could use with these small boards. I have a video <display/keyboard on a similar form factor which I'd really like to package <with these other two boards and the drives. That would be truly minimalis <for the time. I packed mine in a box I found at DEC (oddball) that was very compact. It also allows for external DC power (battery and solar) as mine has been modded to take mostly cmos parts (CPU, CTC, SIOs, EPROM, 53C80, and some of the losse ttl to 74hct). Power is way down. Allison

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8" drive on a pc controller

by allisonp＠world.std.com

<I wasn't aware that the NEC controller chip had a problem with the step <rate. I stuck with WDC FDC chips in my own applications. It was a problem of how the down counter for timing the steprate was designed. It had a granularity of 1 (8") or 2mS (5.25") and could truncate the first(only) step pulse. There were other paybacks that some designers really liked as the disk interface was more complete for things like head (side) selection, drive selection. When used with DMA it's a fairly sane chip to program. However the PC implmentation is rather badly hacked from the start and has become the defacto standard. If it were done as suggested ack then 8" drive would have been quite easy to do as well. Allison

26 years, 10 months

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z80 timing... 6502 timing

by edick＠idcomm.com

Does the hardare need to be "real" or can it be simulated? That would make it less likely to favor one core over the other. If it's real, it has to be available to both processors and quite identical. Dick -----Original Message----- From: Mike Ford <mikeford(a)netwiz.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 2:26 AM Subject: Re: z80 timing... 6502 timing >>Ooh! A machine code competition. I'm in! I'll do the 6502 and whoop >>EVERYONE'S ass! > >And then you woke up. First what are the rules, 6502 or 65C02, code in Rom >or Ram, what is the code supposed to do? > >My vote goes for something with some graphical element so we can "see" what >is happening. (spinning ball, etc.) > >

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How to read recalcitrant floppies?

by manney＠hmcltd.net

Well, there's Norton disk editor. I've rescued data with it before. It certainly is a time-intensive operation, though! I have a spare license I can loan you if you need one. P Manney manney(a)hmcltd.net Is it illegal to yell "Movie!" in a fire station? >> that have read errors that DOS won't get past, bad sectors and the like.

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Kaypro (fwd)

by siconic＠jasmine.psyber.com

Here is someone in Colorado with many nice Kaypro's they'd like to get rid of. Please reply to the SENDER of the message: Reply-to: DaveG56313(a)aol.com ---------- Forwarded message ---------- Date: Mon, 12 Apr 1999 19:43:42 EDT From: DaveG56313(a)aol.com Subject: Kaypro Are you interested in Kaypro hardware and software? I have four of them (I think it's four) gathering dust in a store room. One is my original Kaypro II with an internal Ramdrive I built from plans I found on GEnie. I think there's another original Kaypro II, a Kaypro IV, and two Kaypro 10's (one with two 20mb hard drives replacing the original 10mb drive. Four of the five are in working order. Software includes a complete shareware library from the local Kaypro Users Group I belonged to. There are also two daisy wheel printers--Diablo 620's. One is parallel; one is serial. Let me know if there is any interest. Dave Green Loveland, Colorado Sellam Alternate e-mail: dastar(a)verio.com ------------------------------------------------------------------------------- Puttin' the smack down on the man! Coming in 1999: Vintage Computer Festival 3.0! See http://www.vintage.org/vcf for details [Last web site update: 04/03/99]

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OT: City Names

by Philip.Belben＠pgen.com

>> > > Just back from Warschau (Poland) - Thanks. And BTW: since Karfreitag >> >> > Where? Oh, you mean Warszawa. Warsaw. ;-) >> >> (You're just lucky that's one of the few polish words without lots of >> accents etc.) Hmm do you want to start another War ? ;) >> >> If you live in a city like Munich you learn about the ways >> of naming a city - and of coure how senseless it is to >> belive in calling a thin worldwide with one single name. Hmm. I generally try and name a city in a language that is spoken in that city - so I am usually careful to write Muenchen, Nuernberg, Braunschweig for Munich, Nuremberg and Brunswick. But I admit that I would probably simply have written Warsaw for Warszawa. The main difficulty is when the language doesn't use Latin characters. I wouldn't even know how to write "Bangkok" in Thai, although I think I could manage "Taipei" in Chinese. (But Taiwanese place names should be transliterated according to the Wade-Giles system still used in Taiwan, rather than in PinYin as on the mainland) Polish is one of the less bad languages for accents - Czech is far worse, to the extent that in the UK we generally use Polish spellings... > Well, maybe you could explain it to me, I'm afraid I don't get it. :^) > I always wondered why Munich sometimes gets shown as Munchen. I can't do > those funny accented characters, (umlauts?) even if I knew what they meant, > just as well, most people around here have enough difficulty with 26 > letters. I don't know how you guys cope with all the extras, not to mention > all this masculine/feminine/neuter gender and case stuff. Confused the hell > out of me. Umlauts are reasonable enough. Gramatical gender is an anachronism that should be abolished as soon as possible. But English spellings (whenther British or American) have been in sore need of reform since before they were standardised... > Good things about living in a single island country that's larger than most > of Europe. > > 1) Everybody speaks English. ('Cepting a few migrants/boat people....:^) > They expose kids to other languages at school, but theres is no real > need/pressure to learn one to a level where conversation is possible. > (Who we gonna practice on/talk to?) > Some do learn Indonesian or Japanese, but most don't bother. What? Have we found in the Aussies a nation who are even worse at foreign languages than the British? I never thought I'd live to see the day! ;-) > 2) You don't need a passport to drive across the road. Or travel 2000km for > that matter. Well, we're like that in the UK, except that the island is smaller. > 3) 240VAC 3 pin sockets are a national standard. That doesn't seem to have helped us... > CNN is about the nearest I get. Upside is that I can now read most of the > Cyrillic alphabet after 4 weeks of watching snippets of Serbian TV news > subtitles! > (Well I can read Belgrad(e) Pristina and Novi Sad anyway) Watch out! The Serbian alphabet is as different from the Russian alphabet (the de facto standard for Cyrillic) as the Polish alphabet is from the English alphabet... (I have somewhere a Yugoslavian banknote. Everything is written on it in four local languages - two using Cyrillic and two using Latin characters. The languages are similar enough that AFAIK nothing needs to be said more than three times...) Philip.

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Don Lancaster was Re: Ebay Mark-8 Plans

by yakowenk＠cs.unc.edu

On 12 Apr 1999, Christian Fandt <cfandt(a)netsync.net> wrote: ] Well, so much for April 1st being the specific "Holiday of Jest" ;-) I much prefer "August Fool's Day". Nobody expects it. :-) Bill.

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Abort, Retry, Ignore, Fail? (Was: stepping machanism

by yakowenk＠cs.unc.edu

I'm almost afraid to ask this, but what language is the Perl interpreter written in? Bill. (K&R C rules! ANSI C is for wimps!) On 9 Apr 1999, Cameron Kaiser <ckaiser(a)oa.ptloma.edu> wrote: ] :: It's stupid to handle errors? Or are you saying one shouldn't be using C ] ::in the first place? ] ] The latter :-) ] ] :: -spc (Not that C is the best language ... ) ] ] I'm still kinda stuck on Pascal, myself. But I loves Perl.

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Abort, Retry, Ignore, Fail? (Was: stepping machanism

by yakowenk＠cs.unc.edu

It is not such a great testimonial when you admit that you like it because they paid you for it. :-) Reminds me of the spoof interview with Staunstrup about C++ ... Bill. On 9 Apr 1999, Ethan Dicks <ethan_dicks(a)yahoo.com> wrote: ] I am presently paying for my classic computer hobby by crafting perl for 50+ ] hours per week at consultant's wages. I *love* perl!

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Signal detection

by CLASSICCMP＠trailing-edge.com

>Could anyone tell me how a radio detects signals vs. static? There is a >little gauge on my radio that moves depending on the amount of noise vs. >signal. I would guess that the digitally tuned radios that skip over the >frequencies that are pure static work in the same way. What is this way? Generally the gauge is a reading of the AGC (automatic gain control) level being applied by the radio's IF. There are many other ways to derive this signal, but this is the most common one. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

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Has anybody heard from Wirehead?

by fauradon＠pclink.com

Well I finally got my shipment today. Still no word from him though. Francois >He cashed mine about a month ago and I also Have had very little contact >with him. Last I got was that he was traveling or otherwise swamped by his >job. His last e-mail stated that he'll ship on monday and confirm by e-mail >but I have not received such confirmation... I'm getting impatient too... > >Francois > >>I haven't heard from him either. He cashed my check on April 5, 1999. Let >me >>know if you hear from him. >> >> >

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AMPRO LITTLE BOARD, etc.

by edick＠idcomm.com

Golly! I wasn't aware that they actually put a SCSI controller on the board. That must have been several rev's later than mine. My two boards were the beta and first release. I put a couple of hundred of these into the field because I liked them and they allowed pretty compact packaging. Take a look at some comments in-line below, please. regards, Dick -----Original Message----- From: Allison J Parent <allisonp(a)world.std.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Friday, April 16, 1999 6:35 PM Subject: Re: AMPRO LITTLE BOARD, etc. ><I bought mine new as a kit in '83, as part of the first production run. ><They didn't have HDD support then, and since I made and sold an adapter ><daughterboard to interface to Z-80 processor sockets, one of several, I wa ><not concerned about that. The board always worked reliably and, aside fro ><the occasional need to read a standard diskette, the system was pretty ><complete. > >Mine is only slightly later, has the 5380 scsi chip. > ><Well, the drive attached to my two boards, i.e. the hard drive, is an ST-50 ><that was lying about some fifteen years ago when I happened to need a drive > >The sequence of disks over the years for the HDD side: > > xybec and st506 bought new in 82(late). Still have both. > Adaptec, and Quantum D540 (31mb) much faster. > the adaptec died and the xybec was in with a st251 for a while > then the fujitsu 3.5" scsi drive. > I was propping the door to a room in the basement with a couple of 10MB RODIME 3.5" drives which might work really well with this arrangement. I once ran one of these with a 1"-high 3.5"Sony drive which a PC believed was a 1.2MB drive. Maybe I can fool the FDC drivers into doing a similar thing. That would be handy. There's no "standard" 3.5" driver for CP/M. > ><>supported. The host interface was very similar in concept and nearly ><>in execution as IDE. >< >< ><The history included in the IDE spec clearly indicates that it was patterne ><after the 1003-WAH board (of PC/AT fame), which is the PC-bound eqivalent o ><the 1002. It uses the same IC's, hence the same command structure and bit > >Here we go again... I DIDN'T SAY IT WAS IDE. I said it was similar in >respect that it was a bus level interface for a controller and predates >IDE. I do know that the wd1003 was what the IDE base design was patterned >after. No, you surely didn't say that! It doesn't use the same cable definition or any thing like it. It just happens to use a 40-conductor cable. The reason I said I'd try modifying the firmware to talk to an IDE drive is that there is reason to believe that the command structure is identical although the hardware would have to be modified to load the registers as it's done on the 16-bit -WAH controller. The fact is that the 1000-05 and the 1002-05 bridge controller boards use the same chip (WD1010-05) as the HDD interface. That's where the command registers are located and they'll require programming in the same way. Since the IDE drive has, essentially, the same register set on it to accomplish the controller functions, and the register set mapped in the same way as the WD1003-WAH, it should be possible to make it work similarly. ><definitions. I'm inclined to try hooking an IDE drive up in place of the ><1000-05 board and ST-506 drive just to see what it does. I'd imagine they ><emulated it faithfully. > >>From the programming I did in the late 80s with them I'd say they did. > ><The WD hardware required a fair amount of time to do its job, particularly ><the BMAC chip, which is really just an 8042. The access time for which th ><WD controller series was built was a bit slower than the access window fro ><a 4 MHz would consistently allow. Consequently, I put a device specific ><wait-state generator on my adapter daugherboard. It decoded the address an ><generated a wait only for this one device, since the AMPRO guys, or whoeve ><else generates wait-states when they think they're needed could still do i ><on their own for other devices. > >Explains alot. the first hard disk system I had was S100 so the standard >for performance was already set in my mind by '83. > ><Yes. I have a bunch of the ADAPTEC 4070 bridge controllers left over from ><something. They record in RLL code, so the "little" drives I used to use a ><doorstops, etc, (ST506, TM602, SA6-whatever) can be nearly a full CP/M ><"volume," i.e. they hold about 7.2 MB which is nearly the max for a CP/M ><drive size. It works out well. > >I have one of those that replaced the MFM one from way back. > ><I wasn't aware that ZILOG or MOSTEK had 8MHz peripherals, though it doesn' ><surprise me. I ws siphoned off into a bunch of 8748/8751 stuff in mid-1983 ><and stopped following the Z-80 for a while. By the time I was able to com > >Finding them can be tough. the 6mhz are more common. 8530s or 8330s are >easier to find and offer better perfomance. > I'm really not that hot for it, but think it would be charming to put a set of '-H' parts in an early AMPRO Little Board and make it work at 8MHz. The timing should work with 100ns DRAMs. Aside from the PROM, I doubt anything other than the peripherals would be affected by the speed change. Of course the FDC would require a different tap from the clock divider, but everything else should work as is, save, perhaps the PROM. The PROM might work if the clock switch were hacked as well. (I believe there was a little sorcery with switching the clock speed after copying the PROM into RAM, by switching the preset on a counter. What I liked about this was the really sensible packaging you could use with these small boards. I have a video display/keyboard on a similar form factor which I'd really like to package with these other two boards and the drives. That would be truly minimalist for the time. > >Allison > >

26 years, 10 months

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8" drive on a pc controller

by edick＠idcomm.com

I had a number of double-headed drives, including Shugart 851's, Mitsubishi whatevers, Qume DT-8's, and some NEC and Tandon half-height models, all of which were operated at 3 ms. I've got the spec's for all of them so I can verify whether they should indeed operate at that rate. Only the single-headed drives were typically slower, IIRC. The distinction, I believe, is that the "slow" drives use lead screws to position the heads while the quicker ones use a band actuator. What I find puzzling about this is that the 5.25" half-height drives, virtually all of which were capable of the higher speed, were not set up for the higher speed in the default on PC's. I wasn't aware that the NEC controller chip had a problem with the step rate. I stuck with WDC FDC chips in my own applications. Dick -----Original Message----- From: Allison J Parent <allisonp(a)world.std.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Friday, April 16, 1999 6:35 PM Subject: Re: 8" drive on a pc controller ><Please forgive my interloping, here, but my SHUGART and Siemens SD 8" drive ><are spec'd for 6 ms step rate, and the double-headed types for 3 ms. It's ><really best (mechanically) to step these babies as fast as they will go, an ><it's quieter too. > >Be specific on the model as the sa800s and 850s would never do 3ms! Though >the later ones did step faster. The problem with 8" drives are that there >were some that were doing their best at 10-12mS and a few like CDCs 3ms >was the norm. Most fell in around 6mS. > >ALSO, the PC controller uses the 765 chip (or it's core) generally and >that chip can truncate the first step pulse by 1/2mS (8/5"). So the >fastest recommended step rate programming (srthut in SPECIFY command) >is 4mS. I believe it was never fixed. > >Allison >

26 years, 10 months

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temporarily unsubscribing

by max82＠surfree.com

Hi, I'm removing myself from the list until wednesday, since I will be unable to check my mailbox during that period. Please, e-mail requests privately or wait until wednesday. --Max Eskin (max82(a)surfree.com) http://scivault.hypermart.net: Ignorance is Impotence - Knowledge is Power

26 years, 10 months

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