test-drb

test-drb@ccmp.vtda.org

101090 discussions

by sellam＠vintagetech.com

Does anyone have or know where I can get schematics for the Gridcase 1535? Please reply directly if you can help. Thanks! -- Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org [ Old computing resources for business || Buy/Sell/Trade Vintage Computers ] [ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]

19 years, 2 months

HP 16c

by ploopster＠gmail.com

I've read the reviews of the HP 16C online for a long time, and people are always singing their praises. When I'm writing assembler, I always have my HP 28S within arm's reach, and I definitely see its value. Does anyone have information regarding features present in the 16C that aren't present in the 28S? (I already know about the features that are present in the 28S and not in the 16C.) Thanks. Peace... Sridhar

19 years, 2 months

Offers on Ebay

by william.berkeley＠yahoo.com.sg

I have put up a number of DEC gears on Ebay, anyone interested please visit: http://cgi.ebay.com.sg/ws/eBayISAPI.dll?ViewItem&item=300105552355&ssPageNa… Thanks and rgds --------------------------------- Real people. Real questions. Real answers. Share what you know.

19 years, 2 months

Hand-rolling a CP/M machine

by ajp166＠bellatlantic.net

> >Subject: Re: Hand-rolling a CP/M machine > From: Warren Wolfe <wizard at voyager.net> > Date: Tue, 24 Apr 2007 15:13:32 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On Tue, 2007-04-24 at 12:21 -0400, Allison wrote: > > >> Another equally sneeky/sleezy trick was to force NOPs (00h) on the buss >> till you hit the rom address where you disable the force nop logic. >> That's slow (takes 61.4mS at 4mhz) though. > > > Only to a computer... That is .0614 seconds, considerably less than >a tenth of a second. Studies have shown that most people cannot even >detect intervals of less than a tenth of a second. Methinks thou dost >protest too much... > > Gee I really didn't think that needed a smiley. Allison

19 years, 2 months

ST506 / ST412 - never see any 3 1/2"?

by dm561＠torfree.net

Date: Fri, 6 Apr 2007 20:20:24 -0700 (PDT) From: Mr Ian Primus <ian_primus at yahoo.com> Subject: Re: ST506 / ST412 - never see any 3 1/2"? > >Any idea why? I'd love to have a handful of 20mb 3 > 1/2" drives to use > >for various things but I never see them. > > > >I'm talking about drives from Rodime, Seagate, > Lapine, etc... cerca 1985. > > Most were unreliable, Miniscribe comes to mind. Hehe - Don't forget the wonderful Kalok Octa-gone... Octa-went. -Ian ---------------- Ah, yes, Kalok; a name that evokes many memories, none pleasant... (although in my experience the Miniscribes weren't _too_ bad) m

19 years, 2 months

Hand-rolling a CP/M machine

by ajp166＠bellatlantic.net

> >Subject: Re: Hand-rolling a CP/M machine > From: "Ethan Dicks" <ethan.dicks at gmail.com> > Date: Tue, 24 Apr 2007 14:29:35 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 4/24/07, Allison <ajp166 at bellatlantic.net> wrote: >> One other thing.. CPUs.. >> >> I've only mentioned Z80s. > >So far. > >> Others from the junkbox would be: >> >> 8080 (for the three voltage masochist). > >Indeed. But the last 8080 I saw in the field was in a 1970s B&W video game. > >> 8085 (Also makes for simple systems) > >Those are somewhat common if you hang around DEC equipment. As I am. > >> NSC800 run it if you got one. > >Don't know that one - what makes it special? National did a odd mix of z80 archetecture and 8085 interface. It's a Z80 for the programmer and 8085 like for the hardware hack. >> Z180 >> Z280 >> ez80 (in Z80 mode) > >These all look like Z80 descendents to me - I'd probably rarely, if >ever, run across one to harvest. Z180s do end up in the stragest of places. >> 8085s are common and makes a fair CP/M system. One caveat is that some >> (far from all) applicaions software expects a Z80 though, most run on 8080 >> and above. > >Since the Z80 was rather prolific, and should still be easy to obtain, >either from junked equipment or just new for a couple of bucks from a >place like BG Micro, what would be the appeal of an 8085? Just a >variant on the theme, or is there something neat about it that >warrants investigation? Z80s are easy to find/get as are 8085s. >Since a bit of the requirements of such a system turn on the >applications' needs more than the operating system's needs, I can >throw into the mix that the things I'd probably most likely try to run >would be some flavor of BASIC, Wordstar, an Infocom engine, and most >likely a Scott Adams/Adventure International engine - pretty much the >sort of stuff I would have run in the late 1970s through the mid-1980s >if I'd had a CP/M system of my own. I'd say that a few hundred K of >removable storage and a 64 or 80-char-wide screen should take care of >all of those. Infocom games are 80x24 for best results. For storage i'd advise at least a 360k floppy (if you r doing floppy) as anything smaller is cramped. CP/M programs and stuff bit larger (around 512k) storage systems easier. the best example I give for that is: Basic system, PIP ED,STAT, ASM, DDT, LOAD plus the CP/M BDOS assemble and edit on one drive and between the .bak, Hex, OBJ, PRN you can easily fill a 360k disk and then some. So for storage (floppy) I always advise TEAC55F (or GFR strapped for 300rpm) to get two side 80tracks and about 720/780k formatted. Or a 720K 3.5" floppy. IDE disk makes the space issue go away as 8mb is a large drive for CP/M. Allison

19 years, 2 months

RX01 in SIMH - how to do it?

by pechter＠gmail.com

On 4/24/07, John A. Dundas III <dundas at caltech.edu> wrote: > > Henk, > > At 9:56 AM +0200 4/24/07, Gooijen, Henk wrote: > > Hi, > > > >I feel like a fool ... I just can't get an RX01 drive > >configured and attached in SIMH. > > As Joe mentioned, make sure only one device is using the CSR and > vector in SIMH before booting RT-11. Then attach the device to the > container file. > > >If I boot RT11 from a virtual RL02, and do .SH DEV, > >the DX driver is listed as "Not installed". > > Right. It needs to be installed before you use it. For example, > > .INS DX: > > .LOAD DX: > > Now try .SHOW DEVICES and see what happens. > > John > IIRC you could give the RX02 a different CSR and Vector and tell the DY driver the vector and csr at load time to get both in. bill -- d|i|g|i|t|a|l had it THEN. Don't you wish you could still buy it now! pechter-at-gmail.com

19 years, 2 months

cctalk Digest, Vol 44, Issue 72

by dm561＠torfree.net

--------------------Original Message: Date: Tue, 24 Apr 2007 09:20:33 -0400 From: Allison <ajp166 at bellatlantic.net> Subject: Re: Junkbox parts... > >Subject: Junkbox parts... > From: M H Stein <dm561 at torfree.net> > Date: Tue, 24 Apr 2007 03:41:05 -0300 > To: "'cctalk at classiccmp.org'" <cctalk at classiccmp.org> > >A couple of relevant sites: > >http://www.csd.uoc.gr/~hy325/spring-2006/docs/8042.pdf > >http://www.beyondlogic.org/keyboard/keybrd.htm > >mike Thanks for the info. After years of using nicely encoded keyboards the AT/PS2 deal is a mess. Allison ---------------------------------- REPLY: Well, you could always replace the encoder in the keyboard, although I think the matrix has a few more lines than were used in the old days. I've got a bunch of index-card-size SBC terminals (both colour and m/c) that you could use as a kbd>RS232 encoder, but alas, they all use XT type keyboards AFAIK. There are of course commercial PS/2 or matrix<>RS232 encoders, but the ones I use are a little expensive ($100, Hagstrom KE24). Finally, here's more good info re reading a PS/2 keyboard: http://www.computer-engineering.org/ps2keyboard/ mike

19 years, 2 months

Hand-rolling a CP/M machine

by ajp166＠bellatlantic.net

> >Subject: Re: Hand-rolling a CP/M machine > From: "Ethan Dicks" <ethan.dicks at gmail.com> > Date: Tue, 24 Apr 2007 12:01:24 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 4/24/07, Dave Dunfield <dave06a at dunfield.com> wrote: >> > The point of ROM vs RAM at $0000 has been gone over a few times. Do >> > "standard" CP/M machines use a shadow-ROM technique, or what, to >> > cold-start? >> >> There are many ways to accomplish getting RAM at 0, even though the CPU >> has to boot from there. > >I'm with you there. > >> Some systems force a JMP instruction onto the BUS during the first three >> fetches, which transfers control to a ROM at a higher location. > >That seems like it would take a bit of extra circuitry to do. Not bad at all, Three states and one is always 00h. Doesn't take much to do that. The sequency you want is say "JMP FOOOH" or C3h, 00h, F0h I think a pair of 74157s could encode that. Another equally sneeky/sleezy trick was to force NOPs (00h) on the buss till you hit the rom address where you disable the force nop logic. That's slow (takes 61.4mS at 4mhz) though. Allison Allison

19 years, 2 months

Fred Fish's passing

by aek＠bitsavers.org

http://en.wikipedia.org/wiki/Fred_Fish

19 years, 2 months

RX01 in SIMH - how to do it?

by henk.gooijen＠oce.com

Hi, I feel like a fool ... I just can't get an RX01 drive configured and attached in SIMH. If I boot RT11 from a virtual RL02, and do .SH DEV, the DX driver is listed as "Not installed". On SY: is DX.SYS and DXX.SYS, and since RT11 answered to the command ".set rx0 locked" "?KMON-F-File not found SY:RXX.SYS", I copied DXX.SYS to RXX.SYS ... and reboot of course. When I enter ".set rx0 locked" the response is now "?KMON-F-Invalid set parameter". I break to SIMH and enter "att rx0 simrx01.dat" and the SIMH response is RX: creating new file RX: buffering file in memory When I continue, and enter .SH DEV, DX is "Not installed". The CSR for DX is in SIMH 177174, the default 177170 is assigned to DY. I know that both drivers normally have the same CSR, I don't see a problem here. So, how do I attached and access (!) a virtual RX01 floppy? Has anybody used RX01 in SIMH before? thanks, - Henk. This message and attachment(s) are intended solely for use by the addressee and may contain information that is privileged, confidential or otherwise exempt from disclosure under applicable law. If you are not the intended recipient or agent thereof responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify the sender immediately by telephone and with a 'reply' message. Thank you for your co-operation.

19 years, 2 months

Why are these SGI boxes double-high?

by legalize＠xmission.com

It turns out all this SGI gear is coming from Boeing. That means the Onyx 2 Reality Monster is likely to have a nice multi-head configuration :-). Woo hoo! So my question is... why is this Onyx and Challenge pictured in a double-high cabinet? <http://www.dovebid.com/assets/display.asp?ItemID=cpt58902> <http://www.dovebid.com/assets/display.asp?ItemID=cpt58877> Usually when I see a Challenge or Onyx in a photo I see a cabinet that is half the height of these and that includes space for all the boards and drives. So what would you need the extra cabinet space for? More boards and drives or just more drives? -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

19 years, 2 months

Hand-rolling a CP/M machine

by ajp166＠bellatlantic.net

> >Subject: Re: Hand-rolling a CP/M machine > From: "Ethan Dicks" <ethan.dicks at gmail.com> > Date: Tue, 24 Apr 2007 12:01:24 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> One other thing.. CPUs.. I've only mentioned Z80s. Others from the junkbox would be: 8080 (for the three voltage masochist). 8085 (Also makes for simple systems) NSC800 run it if you got one. Z180 Z280 ez80 (in Z80 mode) 8085s are common and makes a fair CP/M system. One caveat is that some (far from all) applicaions software expects a Z80 though, most run on 8080 and above. Allison

19 years, 2 months

Junkbox CP/M system?

by ajp166＠bellatlantic.net

> >Subject: Re: Junkbox CP/M system? > From: "Chuck Guzis" <cclist at sydex.com> > Date: Tue, 24 Apr 2007 11:07:20 -0700 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 24 Apr 2007 at 10:12, Allison wrote: > >> At a minimum. FDC interfaces are more involved as the interface has to >> include data and drive interfaces unless one can find a chip like 2793 >> or 37C65. > >My personal favorite is the WD1770/1772 series. It doesn't do >500Kbps drives (no big deal for CP/M); interface logic is very >minimal. Very simple to program; a 4MHz Z80 should be able to keep >up with the data transfer without breaking a sweat. And it fits in a >reasonably small (28 pin) DIP package. > >But a minimal system might incorporate nothing more than a PIIO or >SIO and simply pass mass-storage requests and console I/O over the >same path to a PC using a formatted message scheme. Makes the CBIOS >coding a walk in the park. If the system is 32k eprom with shadow, 1770/72 SIO, CTC and 64k of ram it's called a AmproLB. ;) Great little system on a board. the LB+ adds a 5830 SCSI interface and that makes SCSI hard disk possible. >Or, one could build the Z80 onto a PC prototype board with its own >local memory as a coprocessor and conduct mass storage and console >I/O over a pair of I/O ports. For many, that may be the best of all >worlds as it relieves one of the problem of terminal and disk >interfacing, power supply and enclosure. Of course, the folks who >want to put their project into a mahogany case with glass front may >not be taken with this idea. :) That would be identical to the DecmateII (and III) CP/M APU board. the board is a Z80, 64k of ram and two ports. The DECmate does disk and display work for it. The Z80 APU for the PRO350/380 is similar. It's been done more than once on the ISA bus (PC). As to the wood and glass case. Anything fits inside that! ;) Allison

19 years, 2 months

Hand-rolling a CP/M machine

by zmerch-cctalk＠30below.com

Rumor has it that Ethan Dicks may have mentioned these words: >On 4/24/07, Allison <ajp166 at bellatlantic.net> wrote: >>One other thing.. CPUs.. >> >>I've only mentioned Z80s.... > >>8085 (Also makes for simple systems) > >Those are somewhat common if you hang around DEC equipment. Or early Tandy laptops... ;-) >>Z180 >>Z280 >>ez80 (in Z80 mode) > >These all look like Z80 descendents to me - I'd probably rarely, if >ever, run across one to harvest. Harvest, shmarvest - Mouser/Digikey carries 'em in stock - wanna 33Mhz Z80 compatible, with access to MMU & whatnot if you choose? $13. Just like everything else computerwise, slower is cheaper... Laterz, Roger "Merch" Merchberger -- Roger "Merch" Merchberger | A new truth in advertising slogan SysAdmin, Iceberg Computers | for MicroSoft: "We're not the oxy... zmerch at 30below.com | ...in oxymoron!"

19 years, 2 months

Dayton (cctalk Digest, Vol 44, Issue 69)

by wdg3rd＠comcast.net

This message has been processed by Symantec's AntiVirus Technology. Unknown00000000.data was not scanned for viruses because too many nested levels of files were found. For more information on antivirus tips and technology, visit http://ses.symantec.com/

19 years, 2 months

Ferranti Argus 700 parts

by jim＠g1jbg.co.uk

I know of an Argus 700 that has been scrapped. Does anyone need any parts? (no processor cards - they've gone to keep another one going). Please contact me off list Jim. Please see our website: www.g1jbg.co.uk

19 years, 2 months

Hand-rolling a CP/M machine

by ajp166＠bellatlantic.net

> >Subject: Re: Hand-rolling a CP/M machine > From: "Chuck Guzis" <cclist at sydex.com> > Date: Tue, 24 Apr 2007 09:35:02 -0700 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 24 Apr 2007 at 12:01, Ethan Dicks wrote: > >> Right. That much I get... so once CP/M is running, it's ordinary not >> to refer to the boot ROMs? There's typically not a requirement to >> keep some low-level BIOSy stuff in ROM? > >Nope. CP/M installations are typically self-contained, though there >are a few systems that keep ROM around for I/O servicing. Since >you'll be writing your own boot code, you can do ROM mapping however >you'd like. A simple way is to keep your boot code and monitor at >0000 and have the boot routine from diskette simply unmap the ROM. >Note that the CBIOS code (which not only provides I/O, but also loads >the rest of the operating system is located in high memory and >doesn't require anything in low memory to get going. True, most (traditional) CP/M system load the whole show in high ram and rom is either in the way or turned off. Non-traditional CP/M approach: rom (and ram) if paged in and out can be a way to park code for the BIOS to keep it out of main ram area. Also non-traditional is putting the entire CP/M+ bios image in Eprom rather than on Disk or floppy system tracks. >One caution here. If you need interrupt service (say, if you're >interfacing a PC keyboard), do not give in to the temptation to use >the Z80 NMI line. NMI vectors to 0066H, which happens to be right in >the middle of FCB2. There are some very messy workarounds for this >for some systems, but the best thing to do is to avoid it. Use a >"regular" interrupt if you need one. I've seen more than a few get bitten by that beastie. My favorite is use mode 2 (Z80 vectord) by adding a LS244 to the bus that is activated by MI/*IRQ/ (interupt ack) to push in a fixed vector or just 00h. In that mode the IV (interrupt vector) register supplies the high byte making it easy to put interrupt routines at the beginning of any 256byte page in ram. >I think that the old Tarbell disk controller used a 82S23 bipolar ROM >to read one sector from disk. That's only 32 bytes, but it was >enough. Just enough! Allison

19 years, 2 months

Another unknown computer panel (is a 2870 panel)

by aek＠bitsavers.org

I located the FE manual for the 2870 in the CHM archives, and it appears to match. I'll get scans of that and the 2860 manuals up in the next couple of days.

19 years, 2 months

Quick survey on equipment

by ajp166＠bellatlantic.net

> >Subject: Re: Quick survey on equipment > From: ard at p850ug1.demon.co.uk (Tony Duell) > Date: Mon, 23 Apr 2007 23:30:04 +0100 (BST) > To: cctalk at classiccmp.org > >> > The problem was that CP/M needs RAM starting at location 0, the >> >TRS-80 has the BASIC ROMs there and starts RAM at, IIRC, 0x4000. >> >> Hmm, same problem as the Model III then (ISTR that had its ROM located at >> $0000 too, hence the reason for the Model IV). > >Exactly. The Model 1 and Model 3 are actually quite similar machines >internally, to the extent that a Model 3 ROM set will run on a Model 1 >(if sutiably addressed). Admittedly the Model 3 makes more use of the Z80 >I/O ports (almost all I/O on the M1 is memory-mapped for some unknwon >reason), but the memory nap, video, etc, are the same. Maybe because the IO instructions are slow compared to something like (8080 neumonics) Mov M,A. Also since they used a Memory mapped video that ate 1k of space along with the 12k of rom why not do the keyboard that way. Actually there are quite a few IO mapped ports on the M1 but the keyboard and Video are in the memory map. Allison > >The M4 has quite a few changes over the M3. It has the >software-selectable memory maps, allowing RAM at location 0 for CP/M. And >a much improvded video section with a 6845 CRTC chip (and not a >fixed-configuration row of TTL of the older 2 machines) thus giving am 80 >column text display, etc. > >> >....The second solution was an add-on circuit board.... >> >> Hmm, sounds like these are probably going to be as easy to get hold of now >> as hen's teeth...? > >I don't recall there being any published schematics for them either, so >if you want to build one you'll have to design it yourself. > >> >> Think I'll just get a Z80 Second Processor for my Beeb instead (far less >> hassle). > >I didn't think those were _that_ common... > >-tony

19 years, 2 months

Junkbox CP/M system?

by ajp166＠bellatlantic.net

> >Subject: Re: Junkbox CP/M system? > From: Holger Veit <holger.veit at iais.fraunhofer.de> > Date: Tue, 24 Apr 2007 15:35:10 +0200 > To: General Discussion: On-Topic Posts Only <cctech at classiccmp.org> > >Allison schrieb: >>> On CF, IOCS16- is honored--but it's not on any IDE hard drive you're >>> going to buy today. >>> >> >> I've heard that was true of any drive over 500mb and have not seen anything >> over 80mb that does. >> >> Me I keep saying if you really need the simplicity of 8b transfers and >> the low cost that comes from a surplus IDE drive just ignore the high 8bits >> and enjoy it. There's no harm from that. So what if half the storage >> is unused, likely the drive is large anyway. >> >You are going to lose the error flags from the status register which a >transferred on D8-15, IIRC. >Also the drive identify command will return only half of the data. >It is not an issue with pure data blocks; you'll then just have 256 byte >blocks rather than 512. Both are minor issues. CP/M cannot use the identify and a bios that uses it to configure is going to grow far to fast. The error bits are a minor problem, sufficient to say if you get an error (low 8bits signal generic error) whats one to do? Answer, not much as something big happened. CP/M doesn't handle errors the bios does. It's simplistic but 99.999% of the time unless there's a programming error where the host and drive are out if sync, errors mean it's time for a new drive. Allison > >-- >Holger >

19 years, 2 months

My X programs [was Dreaming of a lean installation method [was Re: *nix on]]

by mouse＠Rodents.Montreal.QC.CA

Back on 2007-04-11, people asked me about my X software. At the time the FTP area was..rather insufficiently populated. I wrote > I clearly need to push a lot more stuff to the FTP area. Probably > won't happen until after work today, though. I finally got around to this. ftp.rodents.montreal.qc.ca:/mouse/X/ is a bit more populated now. /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

19 years, 2 months

Junkbox CP/M system?

by ajp166＠bellatlantic.net

> >Subject: Re: Junkbox CP/M system? > From: Holger Veit <holger.veit at iais.fraunhofer.de> > Date: Tue, 24 Apr 2007 10:04:49 +0200 > To: General Discussion: On-Topic Posts Only <cctech at classiccmp.org> >>>>snippage of lCD stuff (worthy of its own topic)>>>>>. > >You might infact look for embedded systems with a Z180 or better Z280 >CPU (PLCC84) they have most of the stuff like MMU and DMA already built >in which one needs to make a system with more than 64k. There are >already SRAMs with 128kByte >available, so no longer needs to build complex DRAM refresh schemes. SRAMS to 512k are current. Reality for CP/M applications is that none I know of use more than the base 60K(max!). So any extra ram interfaced either ends up as ramdisk or buffer space for BIOS. >>> Just buffer some data and address lines off for a floppy or IDE >> > interface >> >> From a programming point of view, how easy is accessing IDE compared >> to a typical FDC ('765 or similar)? I did write some assembler to >> access an IDE drive about 12 years ago, but have long since forgotten >> details! :-) >Effectively, the software logic is the same. You have some registers >where you put in head/track/sector information, wait for >some ready status flag and read the data out or feed a block of data in. >Differences exist between the layout of the registers, but are actually >no stumbling block for any Z80 programmer. FDC has one differce from IDE, it is not buffered and if there is no DMA the cpu does PIO and it has to do it fast. So the programming has to be a bit more carefully crafted to grab a byte every 16uS. IDE is buffered so you have all day to transfer the data. >IDE is a little bit more comfortable as you don't have to deal with >low-level disk formatting and bad-block handling. Blocking/beblocking to >convert between 128 byte sectors and 512 byte disk sectors is still >required, unless you leave this to CP/M+ (CP/M 2.2 IIRC didn't have this >directly). OTOH, one could program an FDC to use 128 byte blocks on disk CP/MV2.x does not do deblocking for you but it does provide the software flags and hooks to do it and the code is supplied (on line and in the Alteration Guide). >easily; which then will cause trouble with data exchange to a PC, >however. OTTH, the logic for an FDC is typically more complex than for >an IDE interface, usually because of some monoflop-based data separator, >including some adjustment of resistors/capacitors. At a minimum. FDC interfaces are more involved as the interface has to include data and drive interfaces unless one can find a chip like 2793 or 37C65. >From a practical standpoint I advise people building CP/M systems the following. Don't bother with floppy, it's a complex system and you have many things(including the drive) that may have to be debugged. The idea of using floppy to transfer to PC is quaint and practical but most PCs also have serial lines and that is both easier to do and if done right fast enough, plus it's portable to PC systems that don't have floppy at all. I do suggest Flash or EEprom as ROmdisk and even ramdisk using static ram as one way to have storage but IDE is a viable and generally cheap way to go. IDE drives are easily tested (any old PC can do that) and drive under 1G are usually found in both good condition and near free(or cheap). A good base CP/M system: 1 Z80 (any speed) 2 61256 (64k ram) 1 27256(or28256) 32k eprom (startup) 1 CTC or 8253 (baud clock) 1 Z80 SIO or DART (two serial channels) about 12pcs TTL glue (maybe less) 1 IDE drive This can be hand wired (wirewrap or point to point) and with that few parts it will be small. Parts are available no SMT or unobtainium. Can be done using scrap and salvage. All parts will be through hole. Performance will be good if the Z80 is 4mhz or faster. With a 4mhz Z80 and IDE drive of at least 8mb useable space it will perform as well or better than most S100 and SBC systems discussed. With a 8mhz z80 it will be fast. It will run all the CP/M software and with a larger disk (say 40mb usable or larger) you can download extensive amounts of software to the hard disk. If done right the 32k Eprom can hold a debug monitor, hard disk formatter and also an image of CP/M (with room to spare) so that startup is eased. > >Personally, I tend to use CF<->IDE adapters and build the common three >circuit TTL-IDE interface. I do not have CF is my junkbox(yet). I do have a boatload of old but known good IDE drives. Once I got over my personal dislike for wasting half the drive and stopped using D8-15 the interface is both simple and qualifies as "junkbox". Allison

19 years, 2 months

Dayton vs. epay

by kahrs＠caip.rutgers.edu

I think anyone who disputes that epay hasn't taken over hamfests is delusional. That being said, there are still vendors who show up at the bigger ones (like Dayton and Timonium) and they make the occasional bargain worthwhile. As far as classic computing is concerned, I don't see Vax 11/750s anymore at hamfests: it's all peecees. That doesn't eliminate the possibility of a mysterious discovery. If the weather is fine (always a chancy proposition at Dayton), then what is finer than digging through boxes of junk for the occasional fine item? Peripherals seem to be in greater supply than processors and cables abound. So, take the good with the bad.

19 years, 2 months

Another unknown computer panel

by aek＠bitsavers.org

well, it's not a 2860 selector channel panel, though the design is contemporary with what you have http://www.thegalleryofoldiron.com/2860.HTM it may be a 2870 multiplexer channel. haven't been able to locate a picture of its CE panel, though.

19 years, 2 months

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test-drb