November 2007 - test-drb@ccmp.vtda.org

by dm561＠torfree.net

---------Original Messages: > From: dm561 at torfree.net > To: cctalk at classiccmp.org > Date: Sun, 25 Nov 2007 06:44:14 -0500 > Subject: RE: FD400 drive troubleshooting <snip> >>>> Which just happens to be the ratio of 300RPM vs 360RPM, so that on a 300RPM >>>> strobe disk w/a 60Hz light the 60Hz bars = 300RPM and the 50Hz bars = 360RPM. >> Hi >> I think you have the ratio backward. The 60 Hz disk for 360 RPM >> can be used for the 50 Hz 300 RPM. >> Dwight <snip> Hi I guess my problem was reading your sentence. It just isn't clear to me where you are saying they are equal and where they are not. The part "60Hz bars = 300RPM and the 50Hz bars = 360RPM" seems to be saying that "300RPM @ 60Hz = 360RPM @ 50Hz". I'm sure I'm reading it wrong but it is still confusing. At least we both agree on the basics and that is all that counts. Dwight --------Reply: Well, I did say "the 60 and 50Hz *BARS*" (as in "stripe" or "band") at the same frequency of illumination (60Hz), but perhaps I should have inserted "the speed at which the bars seem to stop" instead of trying to keep it short and simple (with exactly the opposite effect). OK, how about this: It just so happens that the ratio of 360RPM to 300RPM is the same as 60Hz to 50Hz. Therefore, if you have a strobe disk for a 300RPM drive with both 50Hz and 60Hz bars on it and a 60Hz source of illumination, then you can use the same disk to check the speed of a 360RPM drive, since at 360RPM the 50Hz bars will appear to be stationary. I'm talking about using a 300RPM disk at 60Hz (for the OP and others trying to check the speed of a 360RPM FD400 or equivalent with 60Hz); you seem to be talking about using a 360RPM strobe disk (if you found one) at 50Hz, a somewhat different situation albeit one taking advantage of the same "coincidence". But I think by now both our points have been made abundantly and painfully clear, and I'm glad that we can finally put it to rest and not clutter up the archives further. m

17 years, 5 months

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FD400 drive troubleshooting

by dm561＠torfree.net

------------Original Message: Date: Sun, 25 Nov 2007 09:59:52 -0800 From: dwight elvey <dkelvey at hotmail.com> Subject: RE: FD400 drive troubleshooting > BTW, you're wrong; it's 45.1127819548872180451127819548872 > ;-) > m > Hi My calculator didn't show any more digits but your results show that the sequence repeats at 112781954887218045. If I could type underline, one could underline that part and type ... This would indicate a repeating sequence and be even more exactly correct ;) Dwight -----------Reply: You're absolutely right! Uncle! m

17 years, 5 months

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Programming skills (was: Teaching kids about computers...)

by dm561＠torfree.net

Date: Sun, 25 Nov 2007 08:44:13 -0700 From: woodelf <bfranchuk at jetnet.ab.ca> Subject: Re: Programming skills (was: Teaching kids about computers...) M H Stein wrote: >> Why the "but"? Did I imply anything of the sort? Did I say that a >> carpenter should know how to make an electric saw or even repair >> it when it would be a more efficient use of his time and skills to just >> take it to a shop or buy a new one? >> ------ >But it does help if knows how to change the blade. :) >Same with hardware/software -- know your tools. I thought "being proficient in the use of the appropriate tools" kind of implied that... But thanks for making it clear! m

17 years, 5 months

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trs80 items wanted

by g-wright＠att.net

-------------- Original message from "Jay West" <jwest at classiccmp.org>: -------------- > At VCFX I was able to get the last major component for my TRS80 setup > (already have the monitor, drives, and expansion interface). I got the > keyboard unit for $20. > > Looks like all I'm missing is a real tandy power supply for the Model 1 > (yes, I know I can rig something up, but I'm looking for the real mccoy), > and the buffered cable between keyboard and expansion interface. > > Anyone have one of those two items and is willing to trade? > > Jay West > > Jay, I offered you these last month ??? keyboard, PS . you would just have to take the whole expansion unit. not just the cable. never heard back ??? - jerry

17 years, 5 months

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Teaching kids about computers...

by evan＠snarc.net

One of our prize sponsors at VCF East was a company called Minds-On Toys (as a play of the phrase "hands-on") ... The owner, Tim Walker -- if I recall correctly -- went to MIT and studied all sorts of educational topics. He now sells the Digi-Comp replica. It is VERY easy to build and teaches kids about binary math.

17 years, 5 months

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FD400 drive troubleshooting

by dkelvey＠hotmail.com

> From: cclist at sydex.com > To: cctalk at classiccmp.org > Date: Sun, 25 Nov 2007 10:11:29 -0800 > Subject: RE: FD400 drive troubleshooting > > On 25 Nov 2007 at 9:50, dwight elvey wrote: > >> I was thinking about Tony's idea of the multiple and it occurred >> to me that there was an issue. We've been thinking of the >> flashes as instantaneous strobes while they have duration. > > Dwight, I think it's worse than that. There's also the idea of > "persistance of vision" that gets in the way and also makes the > strobe disc work--our eyes do not have instantaneous response and the > only reason a strobe disc really works is because a fixed pattern is > drilled into our optic nerves many times per second. Were this not > the case, one could have a 45 RPM strobe disc, not with 400 bars, but > with, say 4 or 50--but our eyes would likely not register these as a > single continuous event. > > Of course I haven't tried this yet and I really should. > Hi That is why I think the spiral with bars would work the best. Persistance from adjacent bars would only be a small issue at the tops and bottoms of the bars. The eye would tend to follow the spiral. Such spirals could be made for any RPM. In the case of disk drives, one could make three different spirals. Each for a percentage below and a percentage above the exact one. This way, one could quickly see if the speed were within a specific tolerance. Dwight _________________________________________________________________ Put your friends on the big screen with Windows Vista? + Windows Live?. http://www.microsoft.com/windows/shop/specialoffers.mspx?ocid=TXT_TAGLM_CPC…

17 years, 5 months

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FD400 drive troubleshooting

by dkelvey＠hotmail.com

> From: cclist at sydex.com > > On 24 Nov 2007 at 22:27, dwight elvey wrote: > >> I got my math wrong. The fellow is also wrong. >> 45/60 = .75. >> 100/.75 = 133.333.... >> If rounded to 133, you get 45.11278195---- >> Still, using Tony's multiple method, 400 dots >> would work fine. It would be a large disk but >> it would work. > > 45 rpm is 0.75 r/sec. The strobe lamp flashes 100 times per second > (50Hz * 2). So, the disc completes 3 complete revolutions in 4 > seconds. During those same 4 seconds, the lamp flashes 400 times. > > So there needs to be 400/3 bars on the disc if there is to be a bar > exactly underneath the lamp for every flash, or 133.3333 bars, which > causes the problem. If we increase the number of bars to 133 > exactly, the disk will be turning at 100/133 = 0.75188 r/sc or about > 45.1128 rpm. > > If we put 400 bars on the disk, the lamp will flash once for every > third bar passing under it. Not the crisp display we were hoping > for, however--and I don't know what the visual error would be without > trying it. > > At least that's how I compute it. So maybe the guy is right. > Hi Chuck I was thinking about Tony's idea of the multiple and it occurred to me that there was an issue. We've been thinking of the flashes as instantaneous strobes while they have duration. This would, as you state, cause a loss of contrast. This would tend to overlap the dots and white space of adjacent dots. This would indicate that a continuous 400 dots would most likely work poorly. Still, the spiral method should work fine, with just as much contrast as the single row method. One could use the original size dots and spacing. So, I feel that the fellow was incorrect that such a strobe disk could not be made for exact 45 RPM. Now, looking at the 78 RPM problem, the task seems more difficult, for both 60Hz and worst for the 50Hz. Still, three or four spirals with the correct spacing would be enough, even if it didn't come out to a nice integer. Dwight _________________________________________________________________ Share life as it happens with the new Windows Live.Download today it's FREE! http://www.windowslive.com/share.html?ocid=TXT_TAGLM_Wave2_sharelife_112007

17 years, 5 months

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FD400 drive troubleshooting

by dm561＠torfree.net

---------Original Message: Date: Sat, 24 Nov 2007 22:27:04 -0800 From: dwight elvey <dkelvey at hotmail.com> Subject: RE: FD400 drive troubleshooting > http://www.extremephono.com/free_turntable_strobe_disk.htm > > Note that the 50Hz disc is 45.11 RPM > > Cheers, > Chuck > Hi I got my math wrong. The fellow is also wrong. 45/60 = .75. 100/.75 = 133.333.... If rounded to 133, you get 45.11278195---- Still, using Tony's multiple method, 400 dots would work fine. It would be a large disk but it would work. Dwight -----------Reply: If you're saying that he's wrong, that it's not 45.11 but should be 45.11278195 then I can see why you & I are arguing over whether 300/50 = 360/60 or 360/60 = 300/50... BTW, you're wrong; it's 45.1127819548872180451127819548872 ;-) m

17 years, 5 months

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FD400 drive troubleshooting

by dm561＠torfree.net

---------------Original Message: Date: Sat, 24 Nov 2007 10:02:54 -0800 From: dwight elvey <dkelvey at hotmail.com> Subject: RE: FD400 drive troubleshooting >> From: dm561 at torfree.net > ------------Original Messages: >>> Date: Thu, 22 Nov 2007 12:17:31 -0800 (PST) >>> From: Fred Cisin >>> Subject: Re: FD400 drive troubleshooting >>> >>>>Many/most drives have 50Hz/60Hz zebra discs on the flywheel, for using a >>>>flickering fluorescent light. >>> >>> Which just happens to be the ratio of 300RPM vs 360RPM, so that on a 300RPM >>> strobe disk w/a 60Hz light the 60Hz bars = 300RPM and the 50Hz bars = 360RPM. >>> >>> FWIW, >> >> Hi >> I think you have the ratio backward. The 60 Hz disk for 360 RPM >> can be used for the 50 Hz 300 RPM. >> Dwight >> >> ----------Reply: >> Well, unless you're just saying that a 60Hz 360RPM strobe disk (if you had one) >> would also sync at 300RPM under a 50Hz light, I don't see what's backward. >Hi > That is what I said. The disk with 20 bands would work for both >a 360 RPM and 60Hz light or a 300 RPM and 50 Hz light. -------- Gee, I thought that was what *I* said (and you claimed was backward). Let's see; I said that 300RPM @ 50Hz = 360RPM @ 60Hz, and you said that's backward - 360RPM @ 60Hz = 300RPM @ 50Hz. Sounds like the same thing to me (and Tony) except that a 360RPM strobe disk is a lot harder to find than a 300RPM. Sheesh... --------- > Tony mentioned that one could increase the number of bands for the >problem of the 50Hz with a 360 RPM drive. It makes sense. -------- Indeed; glad to hear it. ------- > Tony mentioned that most 8 inch drives were speed controlled by >the mains and as long as the belt was in good shape, using a strobe >wasn't much needed. ----- You really should read more carefully; he didn't say "most," he said "all of mine," referring to his particular collection. In fact, many 8" drives were 24VDC powered, including the Pertec FD400 which prompted me to send (and regret) the original post that started this bizarre exchange... m

17 years, 5 months

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Babbage Calculating Machine Article 1833

by evan＠snarc.net

I'll send you a private message with contact info for Doron Swade. He will know the answers to your questions. -----Original Message----- From: "B. Degnan" <billdeg at degnanco.com> Subj: Babbage Calculating Machine Article 1833 Date: Sun Nov 25, 2007 9:44 am Size: 2K To: cctalk at classiccmp.org New York Weekly Messenger 2-13-1833 Babbage Calculating Machine Article 1833 On the back page of this newspaper is an article that describes in some detail the eye-witness account of a *working* machine: "...the greater part of the calculating machine is already constructed....I have had the advantage of seeing it actually calculate, and of studying its construction with Mr. Babbage himself..." Does this account describe a working computer? To help make this determination I would want to learn more about the error checking capability of this machine, which I assume was used for calculation of significant digits. A described, Babbage's calculating machine could be described as "computer-like" at least. I believe that this article reports the closest Babbage got to a actual working computer. Or just an elaborate calculator. There are no references in the article to what we today would identify as punch cards or programming. Download the PDF http://www.vintagecomputer.net/babbage/charles_babbage_2-13-1833.pdf ...and read for yourself. The article describes error checking and how results are viewed and how log tables could be calculated accurately, for use in astronomy. The article noted that regarding the printer "..less progress was made...". In the 1830's news from Europe would take a few weeks to reach New York, as boat was the only cross-Atlantic communications. Most articles in the paper refer to end of December 1832 events, including the account of the Calculating Machine. Overall there was a lack of contemporary articles about Babbage's calculating machine in 1832-35. I was able to find just the one often quoted article by D Lardner: "Babbage's Calculating Engines" from the Edinburgh Review 59 (1834) pg 263-327. The New York Weekly Messenger article above was printed a year prior, making it among the first known articles about Babbage's calculating machine. The apparent lack favorable press and the loss of funding in 1834 obscured the fact that the machine had a working visual "display" and was probably more complete than people realize. Was the calculating machine programmable? Maybe. Most writings about the Babbage projects were published a generation after the project was cancelled and I don't think that it's possible to discount the notion entirely.

17 years, 5 months

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Booting XXDP+ from a secondary controller

by bqt＠softjar.se

"Bob Armstrong" <bob at jfcl.com> skrev: > Is there a way to boot XXDP+ from a secondary MSCP controller (e.g. CSR at > 760334) ? > > > > This isn't a PDP-11 boot ROM issue - the -11 (a 11/53+ in this instance) > ROM has no problem booting from a secondary controller. > > > > The issue is that, once started, XXDP doesn't know that it should talk to > this alternate CSR address and promptly dies. I don't think so. As far as I know, XXDP don't take any hints from the boot rom code. You need to build a specific XXDP distribution with a monitor using a device driver talking to the controller at that alternate address. Not sure how you would do that. I've never tried getting system device drivers in XXDP to talk to devices at other than standard addresses. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

17 years, 5 months

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Booting XXDP+ from a secondary controller

by bob＠jfcl.com

> Glen Slick (glen.slick at gmail.com) wrote: >On simh it appears that attaching the disk to rqb0 >resulted in a unit 0 drive on the secondary MSCP controller and I >couldn't find any options to configure the unit number. Does XXDP require all MSCP unit numbers be unique? I thought that was just RSTS... You can do this in simh by attaching the xxdp25.rd52 image to the device rqb2, since the primary rq controller just uses drives 0/1. When I did this, I got the same result (i.e. a halt) as before. >Have you tried this on the real hardware yet? On the real hardware >what unit is the drive you are trying to boot on the SQ703? Yes, on the real hardware it doesn't halt; it just seems to hang forever. The dialog goes something like this (I'm retyping this from my VT320, so excuse any typos) - Commands are Help, Boot, List, Map, Test and Wrap. Type a command then press the RETURN key: B/A DU2 Address = 17760334 DU2 ... hangs here .... BTW, I was wrong before; my SCSI controller is actually a SQ739 rather than a 703, but I doubt that changes anything. There are two SCSI devices on the SQ739, an Exabyte 8505 tape drive and a RRD43 (a Toshiba something or other) CDROM. The SQ739 is configured for 17760334 for MSCP and the RRD43 is configured as MSCP unit 2 (i.e. DU2). Maybe there's something wrong with the way I'm making the CD image? Did you do anything special when you made yours? Thanks, Bob

17 years, 5 months

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FD400 drive troubleshooting

by dkelvey＠hotmail.com

> From: ard at p850ug1.demon.co.uk ---snip--->> > Alternatively make a stroboscope disk (either copy the one off a TM100 > pulley, or work out howm many segments you need and write a trivial bit > of postscript to draw it), stick that on the spindle pulley or > direct-drive motor rotor and view it under amins-powered lamp. > Hi For 60 Hz it is easy. If one uses a light like a neon, it will flash 120 times. An LED is just one direction unless one uses a full wave bridge to get a forward pulse on each cycle. As a single phase it is only 60 Hz. One thing to remember is that the LED can't take too high of a back voltage. Most red ones are rated for about 10V someplace. If feeding it with an AC source greater than the LEDs rate back voltage, one should do something to protect it. A series rectifier diode will work and reduce the power in the dropping resistor. A shunt diode will also work but the resistor will conduct on both half cycles. Lets assume we have 120 flashes per second as from a neon since the same disk would work with the 60 flash LED. A disk spinning at 300 RPM does 5 rotations per second. if we divide 120 by 5, we get 24 flashes per rotation. We just need to create a disk with 24 dark and 24 white segments. For a 360, we get 6 rotations a second. That works out to 20 flashes per rotation. That is 20 black and 20 white spaces. This could be printed with a spread sheet and a pie chart print, as I stated before. For 50 Hz, the 300 RPM is easy but the 360 doesn't work out. One gets 16.66 flashes per rotation. The only way I can think to make this work is to make a spiral that would have 50 dark and light strips over 3 revolutions. Ones eye would tend to follow the spiral. I'm not sure how to do this with a spread sheet. Maybe it could be done with some postscript code but I'm not sure how. Dwight _________________________________________________________________ Your smile counts. The more smiles you share, the more we donate.? Join in. www.windowslive.com/smile?ocid=TXT_TAGLM_Wave2_oprsmilewlhmtagline

17 years, 5 months

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Fwd: ZX-81 Euro Meet

by aliensrcooluk＠yahoo.co.uk

Just found out about this (see below). I apologise if someone has already sent an email to the list about it (still behind in my emails). Regards, Andrew B aliensrcooluk at yahoo.co.uk > Amazing that 27 years after its launch there is > planned the 12th annual meet of the ZX Team > in Mahlerts Germany. > > > 11th -13th April 2008 > > www.zx81.de >

17 years, 5 months

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FD400 drive troubleshooting

by dm561＠torfree.net

------------Original Messages: > Date: Thu, 22 Nov 2007 12:17:31 -0800 (PST) > From: Fred Cisin > Subject: Re: FD400 drive troubleshooting > >>Many/most drives have 50Hz/60Hz zebra discs on the flywheel, for using a >>flickering fluorescent light. > > Which just happens to be the ratio of 300RPM vs 360RPM, so that on a 300RPM > strobe disk w/a 60Hz light the 60Hz bars = 300RPM and the 50Hz bars = 360RPM. > > FWIW, Hi I think you have the ratio backward. The 60 Hz disk for 360 RPM can be used for the 50 Hz 300 RPM. Dwight ----------Reply: Well, unless you're just saying that a 60Hz 360RPM strobe disk (if you had one) would also sync at 300RPM under a 50Hz light, I don't see what's backward. The point was that 50/60Hz 300RPM strobe disks are common, and if you're in a 60Hz zone you can use the same disk for 8" and dual-speed drives as well. m

17 years, 5 months

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Comark 1905

by peter＠aumod.co.uk

Hi Alan, You made a posting 5 years ago looking for cct for Comark 1905 Insulation Meter. Did you get any joy? - I also am looking, and as with you, current Comark gave me the brush-off. Best regards, Peter.

17 years, 5 months

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FD400 drive troubleshooting

by dm561＠torfree.net

--------------Original Message: Date: Sat, 24 Nov 2007 00:14:35 +0000 (GMT) From: ard at p850ug1.demon.co.uk (Tony Duell) Subject: Re: FD400 drive troubleshooting > >>Many/most drives have 50Hz/60Hz zebra discs on the flywheel, for using a > >>flickering fluorescent light. > > > > Which just happens to be the ratio of 300RPM vs 360RPM, so that on a 300RPM > > strobe disk w/a 60Hz light the 60Hz bars = 300RPM and the 50Hz bars = 360RPM. > > > > FWIW, > > Hi > I think you have the ratio backward. The 60 Hz disk for 360 RPM > can be used for the 50 Hz 300 RPM. I think you're both saying the same thing. Assuming you're in the States and have a 60Hz light source available, then take the standard '300 rpm 50/60Hz' strobe disk found on, say, the TM100. The '60Hz bars' will let you check a 300rpm spindle (obviosuly), the '50Hz bars' _used with a 60-Hz lamp_ will check a 360rpm spindle. -tony -------------Reply: Yes, I think that's exactly what I said, although I included Canada and any other place that uses 60Hz, and I don't see what's backward about it. I only mentioned this happy coincidence (and almost regret having done so) because I thought perhaps not everyone in 60Hz country was aware that they could use a common 50/60Hz strobe disk off a 300RPM drive to also check the speed of a 360RPM 8" or dual-speed drive. m

17 years, 5 months

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Booting XXDP+ from a secondary controller

by bob＠jfcl.com

> Glen Slick (glen.slick at gmail.com) wrote: >What are you using for the primary and secondary MSCP controllers and >what disk units do you have configured on each controller? What I'm trying to do is very much like you configuration - my real 11/53 has a KDA50 with 2xRF70 drives and the secondary MSCP controller is a SQ703. You can demonstrate my problem with simh, though - build a bootable XXDP+ v2.5 on a RD52 image, and then do this... sim> show cpu CPU, 11/53, NOCIS, idle disabled, autoconfiguration on, 3072KB sim> show rq RQ, address=17772150-17772153*, no vector, 2 units RQ0, 159MB, attached to one.rd54, write enabled, RD54 RQ1, 159MB, attached to two.rd54, write enabled, RD54 sim> show rqb RQB, address=17760334-17760337*, no vector, 30MB, attached to xxdp25.rd52, write enabled, RD52 sim> b rqb0 HALT instruction, PC: 016146 (CLR (R1)) If you attach xxdp25.rd52 to rq0, it'll boot fine - sim> att rq0 xxdp25.rd52 sim> b rq0 BOOTING UP XXDP-XM EXTENDED MONITOR ... etc, etc .... I suspect you have to patch something in the XXDP+ image with UPDAT to get it to talk to the secondary CSR, but I don't know the details. Thanks, Bob

17 years, 5 months

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Commodore PET first shipemnt in mid October 1977.

by swtpc6800＠comcast.net

I found an item based on a Commodore press release in Byte Magazine, February 1978, Page 190. This establishes the first shipment as mid October 1977. Commodore Ships First PET Computers (Photo of Chuck Peddle) The PET computer made its debut recently as the first 100 units were shipped to waiting customers in mid October 1977. Here Commodore Systems Division Director Chuck Peddle is pictured with the PETs undergoing final checkout. Shipments were made about six weeks later than expected, according to Peddle. The delay was due in part to time consuming quality control measures and the material flow problem in starting up the production lines. "In this business," Peddle argued, "six weeks is actually pretty good." Many of the first units were delivered to customers who intend to develop software for the PET. Commodore plans to create a publishing house for programs developed by users as well as employees. The company plans to increase production of the PET computers to several thousand per month by early 1978. The basic PET with 4 K memory is priced at $595, while the 8 K memory version is $795, >from Commodore Business Machines Inc, 901 California Av, Palo Alto CA 94304, (415) 326-4000. You can find a scan of the item here: http://www.swtpc.com/mholley/BYTE/Feb1978/Byte_Feb_1978_pg190.jpg Michael Holley

17 years, 5 months

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Booting XXDP+ from a secondary controller

by bob＠jfcl.com

Is there a way to boot XXDP+ from a secondary MSCP controller (e.g. CSR at 760334) ? This isn't a PDP-11 boot ROM issue - the -11 (a 11/53+ in this instance) ROM has no problem booting from a secondary controller. The issue is that, once started, XXDP doesn't know that it should talk to this alternate CSR address and promptly dies. Thanks, Bob Armstrong

17 years, 5 months

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MIT provides MULTICS source and documentation (DPS-8 simulation)

by aek＠bitsavers.org

> The I/O > on a full blown system is where a modern system might have emulation > problems This is exactly where simulation has been hung up for years. The mass storage and terminal system is complex, with microcoded controllers for tape and disk and dedicated front end processors for terminal/network I/O. KL10 simulation is a cakewalk compared to this (and the KL10 was no small feat of programming). I've dug up some additional information Olin Siebert didn't have, but there is still a lot of internal Honeywell HW/SW documentation on the I/O that hasn't been found. This whole issue has been bounced around on the Multics mailing list and alt.os.multics for years.

17 years, 5 months

35
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*updating* 8088's

by ajp166＠bellatlantic.net

> >Subject: Re: *updating* 8088's > From: Sridhar Ayengar <ploopster at gmail.com> > Date: Thu, 22 Nov 2007 14:28:30 -0500 > To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> > >Allison wrote: >>> Subject: Re: *updating* 8088's >>> From: "Chuck Guzis" <cclist at sydex.com> >>> Date: Tue, 20 Nov 2007 16:38:01 -0800 >>> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> >>> >>> On 20 Nov 2007 at 16:27, Fred Cisin wrote: >>> >>>> Wasn't the PS/2 30 an 8086? (can't remember for sure) >>> Initially. A later version used the 286. The model 25 was, as far >>> as I'm aware, always an 8086. >> >> The model25 was 8088 powered and I think a few others of that series. > >Definitely not. 8086 or better. None ran an 8088. The one I have has an 8088, model 8530-002. Well actually I pulled the board out to use the case for an SB180 with Adaptec SCSI/MFM adpator, a Miniscribe 20mb disk plus reusing the 3,5" disk and power. Made a nice case for that. Been stripping the PCs board since. Must of had a strange one. ;) > >Peace... Sridhar

17 years, 5 months

3
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*updating* 8088's

by ajp166＠bellatlantic.net

> >Subject: Re: *updating* 8088's > From: Sridhar Ayengar <ploopster at gmail.com> > Date: Fri, 23 Nov 2007 04:02:14 -0500 > To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> > >Allison wrote: >>>>>> Wasn't the PS/2 30 an 8086? (can't remember for sure) >>>>> Initially. A later version used the 286. The model 25 was, as far >>>>> as I'm aware, always an 8086. >>>> The model25 was 8088 powered and I think a few others of that series. >>> Definitely not. 8086 or better. None ran an 8088. >> >> The one I have has an 8088, model 8530-002. Well actually I pulled >> the board out to use the case for an SB180 with Adaptec SCSI/MFM >> adpator, a Miniscribe 20mb disk plus reusing the 3,5" disk and >> power. Made a nice case for that. Been stripping the PCs board >> since. > >I've never owned a -002, but I have a -021 in the pile somewhere that >definitely has an 8086. The IBM Internal sales spec sheet I have here >shows the -002 having an 8MHz 8086. > >> Must of had a strange one. ;) > >If it was an 8088, you did indeed. 8-) No question on that. One of the few parts not stripped, have way to many of them and they are mostly useless to me. The 8087 however I did save. Allison >Peace... Sridhar

17 years, 5 months

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Documentation for the AT&T Sceptre Videotex terminal

by classiccmp＠memory-alpha.org.uk

Hi, >....remap "Caps Lock" to be "CTRL" on my Model M's (along >with swapping ~ and ESC). Those are two of the things I detest the most about "modern" AT-style keyboards. "ESC" should be top left and "Ctrl" should be immediately below the "TAB" key. Oh, and most importantly, "Return" *SHOULD* be "J" shaped (or at least horizontal) rather than these annoying vertical ones we're subjected to nowadays....I'm forever hitting "#" by mistake, even to this day. Other than that they're OK; though I'd rather have the function keys down the left hand side of the keyboard where they belong! :-) >....If you use a keyboard long enough, you'll actually get used to >its key placement just fine, no matter how annoying it is at first, >I guess. With the sole exception of the "Return" key, I agree with you 100%. TTFN - Pete.

17 years, 5 months

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FD400 drive troubleshooting

by rcini＠optonline.net

All: As you all know from previous posts, I?m having trouble with the drive system on my IMSAI. While I wait to receive a memory board and some other stuff from a friend of mine, Herb Johnson gave me some new energy in looking at the existing iCOM Frugal Floppy system. This system uses Pertec FD400 drives. One works perfectly, the other one has consistent CRC errors as evidenced by the CRC light on the drive cabinet, and BDOS errors reported by CP/M. I ensured that the spindle is engaging the diskette hub, and I also cleaned the heads using a wet cleaning diskette. Is there any common failure mode on this model of drive that I should start tracking down? I looked over the maintenance procedures for the drive and many if the tests allude to a diagnostics program that can manually control the spindle and head stepping. None of the iCOM manuals I have provide diagnostics code for manually controlling the drives in this manner. Before I start coding, does anyone have diagnostics code I can use? I found some code in the SIGM archive (for the iCOM 3712 controller) but it doesn?t seem to work properly with this controller. Thanks. Rich -- Rich Cini Collector of Classic Computers Build Master and lead engineer, Altair32 Emulator http://www.altair32.com http://highgate.comm.sfu.ca/~rcini/classiccmp

17 years, 5 months

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FD400 drive troubleshooting

by ajp166＠bellatlantic.net

> >Subject: FD400 drive troubleshooting > From: "Richard A. Cini" <rcini at optonline.net> > Date: Wed, 21 Nov 2007 19:54:46 -0500 > To: "Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >All: > > As you all know from previous posts, I?m having trouble with the drive >system on my IMSAI. While I wait to receive a memory board and some other >stuff from a friend of mine, Herb Johnson gave me some new energy in looking >at the existing iCOM Frugal Floppy system. > > This system uses Pertec FD400 drives. One works perfectly, the other one >has consistent CRC errors as evidenced by the CRC light on the drive >cabinet, and BDOS errors reported by CP/M. I ensured that the spindle is >engaging the diskette hub, and I also cleaned the heads using a wet cleaning >diskette. Get in there and scrub the head with a swab. I found the wet disks didn't cut it long ago. Make sure the spindle speed is good and not irregular. Try swapping drives A and B and se if the problem moves with the drive or not. Just to make sure you not having a issues with something else. > > Is there any common failure mode on this model of drive that I should >start tracking down? Everyone I'd seen either had fallen apart mechanically (broken hubs, doors or other plastic) or the drive motor had gone noisy or mechanically flakey. NOTE: those motors often had bronze (oilite) bearings that dried out and then became oval or other wise out of useful shape. It was a side effect of lot of hours and the belts side tension. Result is the motor speed is uneven. I've seen bad boards too, usually tossed the board and salvaged from another mechanical pig. > I looked over the maintenance procedures for the drive >and many if the tests allude to a diagnostics program that can manually >control the spindle and head stepping. None of the iCOM manuals I have >provide diagnostics code for manually controlling the drives in this manner.. There maybe diags but your on you own to find them. > Before I start coding, does anyone have diagnostics code I can use? I >found some code in the SIGM archive (for the iCOM 3712 controller) but it >doesn?t seem to work properly with this controller. What controller (CHIP on the FDC board)? Allison > Thanks. > >Rich > >-- >Rich Cini >Collector of Classic Computers >Build Master and lead engineer, Altair32 Emulator >http://www.altair32.com >http://highgate.comm.sfu.ca/~rcini/classiccmp

17 years, 5 months

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Documentation for the AT&T Sceptre Videotex terminal

by classiccmp＠memory-alpha.org.uk

Hi, > So, uhm, am I the only person here that actually quite *liked* >the ZX81 keyboard? I never actually *liked* it, though I didn't especially dislike it either. And it was certainly streets ahead of the Spectrum's keyboard; *THAT* is one of my all time most hated keyboards....makes my flesh creep just thinking about it....uuuurghhh....<shudder>. TTFN - Pete.

17 years, 5 months

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*updating* 8088's

by ajp166＠bellatlantic.net

> >Subject: Re: *updating* 8088's > From: "Chuck Guzis" <cclist at sydex.com> > Date: Tue, 20 Nov 2007 17:01:14 -0800 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 21 Nov 2007 at 0:52, Ensor wrote: > >> I spent many happy hours running CP/M programs "under" MS-DOS on my V30 >> machine. >> >> Anyone remember the name of the program which facilitated this? > >Nope. Haven't a clue. 22nice and there were a few others. Allison > >Cheers, >Chuck

17 years, 5 months

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Access to IOPAGE Registers using PDP-11 Opearting Systems

by bqt＠softjar.se

ons 2007-11-21 klockan 12:00 -0600 skrev "John A. Dundas III" <dundas at caltech.edu>: > Jerome, > > I can speak for RSTS with some authority, RSX with somewhat less authority. > > At 9:17 PM -0500 11/20/07, Jerome H. Fine wrote: > >I doubt that RSX-11 or RSTS/E allow a user access to the IOPAGE > >even via PREVIOUS DATA space. Can anyone confirm this assumption? > > Address space in the I/O page for RSTS jobs (processes) was not > directly available. The APRs are always controlled by the OS. It > MIGHT be possible for a privileged job to use PEEK/POKE SYS calls to > access the I/O page in the way you suggest but it would be > particularly difficult. I thought RSTS/E had some way of remapping the address space as well. Can't you remap parts of your memory to some shared region, for example? > RSX had a bit more flexibility (opportunity) in this regard. I > believe you can set up a CRAW$ (create address window) directive in > either Macro or Fortran to achieve the desired result. Yes with reservation. CRAW$ (create address window) is as a part of doing dynamic remapping of your address space. However, CRAW$ always required a named memory partition. You cannot create an address window to an arbitrary memory address. Also, the memory partitions have protections and ownership associated with them. On most systems, CRAW$ cannot get you access to the I/O page, simply because normally you don't have an address space and a partition associated with the I/O page. But if such a partition is created, then CRAW$, in combination with MAP$ would allow you to access the I/O page. The same thing can also be achieved even without CRAW$/MAP$, since you can specify mapping that your task should have already at task build time, with the COMMON and RESCOM options to TKB. Johnny

17 years, 5 months

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Fwd: [alt.sys.pdp11] further collection reduction - TU80 availabl

by legalize＠xmission.com

This message has been forwarded from Usenet. To reply to the original author, use the email address from the forwarded message. Date: Thu, 22 Nov 2007 17:16:11 -0600 Groups: alt.sys.pdp11,comp.sys.dec,comp.os.vms,comp.sys.dec.micro From: "Lee K. Gleason" <lee.gleason at comcast.net> Subject: further collection reduction - TU80 available for free Id: <cL6dnat5DsemkNvanZ2dnUVZ_jWdnZ2d at comcast.com> ======== Free for pickup in Houston, Texas, near TC Jester and the North loop. This is a 9 track, reel to reel tape drive, it comes in a half height rack. It accepts tapes up to full size 2400 foot. Speed 25 IPS start/stop mode, 100 IPS streaming mode. Density is 1600 BPI. This TU80 was lightly used, and then stored in the back bedroom for the last 12 years or so. It was working when I stored it, don't have anything to test it with now. Here's your chance to own a piece of computing history! -- Lee K. Gleason N5ZMR Control-G Consutlants lee.gleason at comcast.net

17 years, 5 months

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VAXmate for Windows

by ajp166＠bellatlantic.net

> >Subject: Re: VAXmate for Windows > From: Adrian Graham <witchy at binarydinosaurs.co.uk> > Date: Thu, 22 Nov 2007 21:49:48 +0000 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 22/11/07 14:03, "Allison" <ajp166 at bellatlantic.net> wrote: > >>> This is why I've kept some ST225s behind. I'm pretty sure both VAXmates are >>> hard driveless, though I can't really speak for the boxed one as I've never >>> really delved in further than below the top foam :) >> >> Generally thy are. Theres a seperate underbox that adds the hard drive >> and controller. > >Ah yes! I remember those now from somewhere like the DECdirect catalogues, >though I never saw them in the field....must've been too expensive for our >customers. > >>> Yep, the one I remember using was a PCSA terminal. This was shortly before >>> we went through the sheer pain of a PCSA to LANMAN migration with Pathworks >>> V5, that's a few weekends of my life I'm not going to get back, heh. >> >> It was during my time at DEC and they wer like flies there. I still >> have kits for PCSAV4 and V5. > >Mostly the same here, I'm a CDDS hoarder, but lost the PCSA floppies I had >many moons ago. I have the complete slipcase kits with PAKs, TK50s and floppies (5.25"). However with more modern PC OS (95 on) having DECnet as a networking option along with LANman I haven't used it much. I have the uVAXes! Allison > >-- >Adrian/Witchy >Binary Dinosaurs creator/curator >Www.binarydinosaurs.co.uk - the UK's biggest private home computer >collection? >

17 years, 5 months

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*updating* 8088's

by ajp166＠bellatlantic.net

> >Subject: Re: *updating* 8088's > From: "Chuck Guzis" <cclist at sydex.com> > Date: Thu, 22 Nov 2007 12:41:07 -0800 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 21 Nov 2007 at 7:32, Allison wrote: > >> >> Anyone remember the name of the program which facilitated this? >> > >> >Nope. Haven't a clue. >> >> 22nice and there were a few others. > >That was intended as a bit of mock humility... :) > >Cheers, >Chuck ;) Yep, and I've found people that used it have forgotten it existed along with many other still useful tools. Allison

17 years, 5 months

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FD400 drive troubleshooting

by dm561＠torfree.net

Date: Thu, 22 Nov 2007 07:58:17 -0500 From: "Richard A. Cini" <rcini at optonline.net> Subject: Re: FD400 drive troubleshooting >The way that the service manual tells you to check the speed is the pulse >width on a specific test point on the PCB. I was just going to use a laser >tach on the spindle...but I have to get a tach first :-) ----- Strobe disk?

17 years, 5 months

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Documentation for the AT&T Sceptre Videotex terminal

by dm561＠torfree.net

-------------Original Message: Date: Tue, 20 Nov 2007 18:31:10 -0800 From: "C. Sullivan" <feedle at feedle.net> Subject: Re: Documentation for the AT&T Sceptre Videotex terminal On Nov 20, 2007, at 1:36 PM, Mark Meiss wrote: > It consists of a base unit that's somewhere around 13" x 11" x 4", > connected to a (fairly wretched) chicklet keyboard with a standard > 4-conductor telephone handset cord. The keyboard is powered by a > 9-volt battery. On the back of the main unit are connectors for > power, the keyboard, RS-232C (DB-25 female), composite video out, and > audio out. I had an AT&T SCEPTER terminal that was used with the Gateway service offered in Southern California from Times-Mirror/Pacific Telephone. It had a 1200 baud Bell 212-style modem built in. Also, the keyboard was infrared on the model I had. <snip> Gateway was a killer service back in 1983. It was expensive, but it was a lot of fun. And I remember dialing up BBSes with the SCEPTER terminal when my C-64's power supply crapped out... --------------Reply: Yeah, I have one of those (keyboards) somewhere in the pile and mine's IR as well, with the Gateway sticker still on the back. No worse than a PET to type on (if I had something to type to ;-) No Windows key either and not supported by Microsoft, so Woodelf would probably like it... m

17 years, 5 months

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VAXmate for Windows

by ajp166＠bellatlantic.net

> >Subject: Re: VAXmate for Windows > From: Adrian Graham <witchy at binarydinosaurs.co.uk> > Date: Thu, 22 Nov 2007 00:03:30 +0000 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 19/11/07 14:23, "Allison" <ajp166 at bellatlantic.net> wrote: > >> If the VAXmates have the optional hard disk box mind the cooling if RD32 >> (ST250? 40mb) as it ran very hot and tended to fail. The RD31 (st225 20mb) >> was lower power, cooler and far more reliable. > >This is why I've kept some ST225s behind. I'm pretty sure both VAXmates are >hard driveless, though I can't really speak for the boxed one as I've never >really delved in further than below the top foam :) Generally thy are. Theres a seperate underbox that adds the hard drive and controller. >> If you make it operational the VAXmate was a PCSA(Pathworks) terminal >> with Ethernet access to shared and private files on VAX/OpenVMS. The >> result made it a very useful system. Typical VAXmate had 2MB of ram >> some had 4, back then that was a large amount. > >Yep, the one I remember using was a PCSA terminal. This was shortly before >we went through the sheer pain of a PCSA to LANMAN migration with Pathworks >V5, that's a few weekends of my life I'm not going to get back, heh. It was during my time at DEC and they wer like flies there. I still have kits for PCSAV4 and V5. Allison > >-- >Adrian/Witchy >Binary Dinosaurs creator/curator >Www.binarydinosaurs.co.uk - the UK's biggest private home computer >collection? >

17 years, 5 months

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Emulex QD33 and Seagate Sabre drive...

by ian_primus＠yahoo.com

I've been attempting to get a MicroVax II set up with a working, large hard drive. I have an Emulex QD33 Qbus SMD controller, and I'm trying to get it to work with a Seagate Sabre 9720-1230 hard drive. It's listed as being compatible with this controller in the manual. So far, I've gotten everything hooked up, and I can get into the controller's firmware by depositing various values at the >>> prompt. After entering the relevant settings (from the manual) for the hard drive, the controller will sort-of talk to the drive. It shows it as being available, but when I try to format it, the drive makes a buzzing noise for about 30 seconds, then I get the message that "This operation timed out". When I answer the error message with the enter key, the buzzing from the drive stops. This buzzing sounds like fast seeking, but it's not what I would expect a format to do, I am expecting more of a slow clunk... clunk... clunk... tapping noise as it seeks, and formats the drive. The CYL: display on the LCD of the drive never increments. I've tried various dip switch settings on the drive itself. The drives I have were originally used with a Wang computer system, but other than the faceplates being painted "Wang light brown" I don't know what other differences there might be. Their sector switches are set for 22 sector, so I entered that into the firmware. My next attempt, I'm going to try and change it to the default listed in the Emulex manual - but as long as the firmware and the drive agree, I don't think it much matters. I've tried different cylinder addressing modes, and both SMD modes (dip switches on the back of the drive) and no change. I've tried two identical hard drives, and get the same result, so I don't think I've just got a bad HDA. Both drives spin up and don't fault. Any ideas? -Ian

17 years, 5 months

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cleaning house (actually shed)

by chrism3667＠yahoo.com

I have a few AT & T monitors (mono) I'm either giving away or throwing out. These were used w/the 6300 (640 x 400). One I found in someone's trash, the other in someone's yard (it was sitting out there for quite some time) in the snow. I turned both on 6 months to a year ago, and both worked, exhibited no noticeable screen burn, but one rolls, the other jitters. Free for shipping. If you think I'm nuts for even bothering to offer them, you're likely correct, but I hate throwing (most) anything away w/o seeing if someone can make use of them. Also 2 Atari (520ST etc) monitors, one mono, one color. Condition unknown. Found them in the trash too. Cables were snipped. There's a growing contingent of yuck-yucks 'round these parts who must think copper=gold. These were also exposed to some moisture, but not submerged. Both sets operate at about the same frequencies as a Tandy 2000, NEC APC III, and other TTL 400 line units. I also have ~2 dozen NOS SASI boards by Adaptec. I can e-mail a jpeg to any interested parties. About 1/3 are in anti-static bags, the rest wrapped in some other kind of clear plastic. 2$/plus shipping. They're driven by an 8085. I may have 2 or 3 Tandy 1000's for phree or close. Eventually I'll be unloading a few 2000's also, but those might have an issue (changing the video mode in BASIC cause the screen to lock up - ???). They belonged to a developer dude, so I'm wondering if he tinkered with them. Or maybe, just maybe the trace wasn't cut as required to upgrade the mono graphics cards to color, along with the addition of necessary ic's. Will have to check... ____________________________________________________________________________________ Get easy, one-click access to your favorites. Make Yahoo! your homepage. http://www.yahoo.com/r/hs

17 years, 5 months

1
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pt210 printing terminal manuals

by dgriffi＠cs.csubak.edu

I've scanned and OCRed the Radio Shack pt210 printing terminal users manual and service manual. If someone wants them right now, please email me. I'm waiting for Howard Harte to grab them from my super-secret website to put it in his archive of manuals. -- David Griffith dgriffi at cs.csubak.edu

17 years, 5 months

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*updating* 8088's

by ajp166＠bellatlantic.net

> >Subject: Re: *updating* 8088's > From: "Chuck Guzis" <cclist at sydex.com> > Date: Tue, 20 Nov 2007 16:38:01 -0800 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 20 Nov 2007 at 16:27, Fred Cisin wrote: > >> Wasn't the PS/2 30 an 8086? (can't remember for sure) > >Initially. A later version used the 286. The model 25 was, as far >as I'm aware, always an 8086. The model25 was 8088 powered and I think a few others of that series. Allison >Cheers, >Chuck > >

17 years, 5 months

2
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Sun 3/4 updates

by compoobah＠valleyimplants.com

Al was right about the Sun 3/200 - it was the PROM - more specifically the complete absence of the PROM - that left the diag lights on all the time. That board's been shelved for a while. The 4300 is up though - it was the NVRAM (someone had put it in backwards at some point during the board's lifetime). Fortunately I had another 4300 board (suffering from the "all lights on" plague) that I grabbed the NVRAM from and it now works fine (but 200+MB of memory makes the diag boot excruciatingly slow).

17 years, 5 months

1
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*updating* 8088's

by ajp166＠bellatlantic.net

> >Subject: Re: *updating* 8088's > From: "Chuck Guzis" <cclist at sydex.com> > Date: Wed, 21 Nov 2007 16:27:41 -0800 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 21 Nov 2007 at 18:11, Jim Leonard wrote: > >> Could you quantify "lame"? I used a 386sx-16 for years and it was >> always faster (visibly, not just via benchmarks) than the 12MHz 286 I >> had access to. > >My own experience was the opposite. I had a 16 MHz 386sx that was >visibly *slower* than a 12MHz 286 that I also had. It was very >cheap and eventually just quit working reliably all on its own. >Perhaps that was an artifact of early SMT. OTOH, I still have a >couple of 386DX systems that have worked flawlessly since the day I >bought them. One uses DIP for memory; the other uses SIPPs. I have a SIIG 3000 Is a 3x4x12" box with VGA, RS170 video, 2 serial, 1 printer port and one slot for modem or NIC. IT's 386sx1/6 and my only beef with it is it maxes out at 5mb (1mb installed and 4mb of simms). Runs good uses wall wart for power and makes a killer linux router/nat box with a 400mb drive and 3.5" floppy. Beside being a good router it's small, a good reason to keep it. Allison > >So, perhaps my own was a victim of bad design. I never was even >tempted to purchase another, so bad was my experience. It's short life and bad design may be an indicator. Allison > >Cheers, >Chuck

17 years, 5 months

1
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Teaching kids about computers...

by evan＠snarc.net

And don't forget Lego Mindstorms! Doesn't teach the hardware but it is much more fun than I ever had in LOGO back in the fourth or fifth grade ... I forget which. -----Original Message----- From: Michael Lee <mikelee at tdh.com> Subj: Re: Teaching kids about computers... Date: Wed Nov 21, 2007 11:17 am Size: 3K To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> This is actually one of the topics I'm most interested in. I gear my collection towards teaching and showing kids, as well as the nostalgic adults. Over the years, I've been surprised by some of the reactions, so I found it best to adapt to the interest level of the audience. For fundamental computing and electronics, it seems to be best to go back to the basics. A lot of the books available either go too much into the history of computing, or get into topics/details that quickly lose the interest of a kid. It seems to be best to relate something they are used to in modern day and work back to the origins. For example, a xbox, it's basically a computer, it has a CPU, hard drive, memory and then other "blocks" such as graphics processing, networking etc. Those are easy to relate back to "how it works." Basic I/O, what is actually on the game disk, how and what makes "online" work, and what the machine is doing in the background. This easily then can lead to small projects and some programming. From there it can be basic logic functions (AND/OR/NOT) and the simple concepts of programming and making things happen. Depending on the interest and geek level of the kid, there are many hobby books that explain this well. I don't know if "vintage" computers is the best way to start as I found a lot of kids (esp. 9yo) are turned off by "it's just old crap" But can easily lead into more of the origins. Something "new" is good to start. There are a good number of hobby kits like the BASIC STAMP now that can teach both the electronics and computing aspect, which then can lead into other things. A little simple micro-controller kit, with a little instruction on logic, electricity and electronics can go a long way. Making stuff, and making stuff happen is always a plus, so a soldering iron lesson with an interesting kit always works too. But once again, all depends on the interest level. Mike Lee Geek Museum A funny story with where things might lead: I got a rotary dial phone in my collection to use with an acoustic coupler. A four year old sees this, and has no problem with the phone, nor the rotary dial. He understood the concept it's just a different user interface, but what got him was that it was wired down. He had never seen a phone handset with a cord attached. So this lead to interesting show and tell about telephone technology to a four year old. Jules Richardson wrote: > > So the boy (9yr. old) was asking last night about how computers > work... any recommendations for good books for learning the basics > from? I think I started out with a Sinclair Spectrum and its BASIC > manual, but I really don't recall now where I found out about the > fundamental building blocks of [typical] computers and how a CPU > worked. There must be a good 'classic' "how computers work" type of > book which avoids going on about PCs and Xboxen... > > I figure I should find him one of those kids electronics projects kits > too (I think that was where I got my first exposure to logic gates > from at about the same age) and also some old 8-bit machine to play with. > > I can get a Spectrum / BBC micro shipped over in a few months, but > something US-built might be better; any thoughts? I did wonder about a > C64, but maybe it'd be better to start with something a bit more > simple? i.e. probably something Z80 or 6502-based (just because > there's more resources devoted to them), generic cassette data > storage, basic video abilities etc. > > (You know, I don't recall seeing a 'how to introduce kids to vintage > computing' thread on here before :-) > > cheers > > Jules >

17 years, 5 months

3
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"intelligent" disk drives

by dm561＠torfree.net

Date: Sat, 17 Nov 2007 21:59:02 +0000 (GMT) From: ard at p850ug1.demon.co.uk (Tony Duell) Subject: Re: "intelligent" disk drives <snip> >As an aside, IMHO one of the worst mistakes commodore made was that the >8050 could not at least read the disks of the earlier drives. >-tony -------- Sort of unavoidable because to get the 500MB/side they went to 100TPI drives. Not as big a problem then as it may be today, because the high price of the 8050/8250s tended to put them into a different market, mostly business and institutional, where price and compatibility with the smaller and cheaper units wasn't usually an issue. And of course the IEEE bus was compatible so you could easily convert among drives (until the serial versions came along) as long as you had one of the (also expensive) IEEE<>IEEE cables. m

17 years, 5 months

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Keyboards (in general)

by tsw-cc＠johana.com

woodelf <bfranchuk at jetnet.ab.ca> wrote: > der Mouse wrote: > > > I don't recall seeing a computer keyboard that *is* lowercase, ever. > > Modern keyboards are generally connected to systems that map alphabetic > > keystrokes to uppercase and lowercase depending on other state, and > > have keys ("Shift") designed to provide that state, but the keyboards > > themselves have only one case of alphabetic key, and in every case I > > can recall seeing, that case is upper. > > I stand corrected ... the only keyboard without a shift key I have seen > is a TTY's. > > > /~\ 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 > > You are a bit mistaken. TTY's DID have shift keys. On the five level machines (28, 32, etc.) there was a LETR and FIGS shift. On later machines, like the 33 and 35, there was an actual key labeled 'SHIFT'. While it didn't make upper and lower case letters, it did take the alternate graphic on the keyboard. On the 33/35 machines, it used a "bit paired" sequence where the difference between the 'shift' and 'unshifted' code was 0x20. This led to some weird pairings like '+' and ';'. Some shifts were locked out (zero might have shifted to be space, and vice versa, but they were separate keys. Later model devices, Teletype 37 comes to mind, had both upper and lower case. Many early CRT terminals didn't have upper case letters either. The ADM-3 had lower case as an option. Some of the portable Silent 700's (I remember having one) didn't have lower case. Those that had lower case used 'miniature letters' not ture lower case. I'm sure there are other examples. Keypunches are another catagory. ____________________________________________________________________________________ Be a better sports nut! Let your teams follow you with Yahoo Mobile. Try it now. http://mobile.yahoo.com/sports;_ylt=At9_qDKvtAbMuh1G1SQtBI7ntAcJ

17 years, 5 months

2
1
0 0

*updating* 8088's

by ajp166＠bellatlantic.net

> >Subject: Re: *updating* 8088's > From: woodelf <bfranchuk at jetnet.ab.ca> > Date: Mon, 19 Nov 2007 20:39:49 -0700 > To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> > >Chuck Guzis wrote: > >> Well, there's clock speed and then there's "apparent clock speed". >> Let's see, a 16MHz 80386sx is equivalent to what, a 10MHz 80286? Actually it's teh other way around the 386 was more efficient than 286 for the same clock speed. >So what speed does the memory run at is my question and how wide? The SX narrows teh bus bandwidth so the memory is cycled either faster to make up for it or has fewer idle states (bus availability). that meant using 60ns 30pin simms. >Playing around with homebrew micro design I am working on, a 500 ns >memory cycle ( 2Mhz ) is about as fast as you can go with standard >parts about 150 ns access time. My limiting factor is not memory >speed but EEPROM and I/O chips dead slow speeds. Those speed limits are consistant with pre 1978 parts for ram and even in 1979 I had some semistatic rams that were 200ns. Eproms were always slow and didn't break the 250ns barrier until around 82 but the mask roms were quite a bit faster. I build with 6 and 10mhz z80s and 12mhz 8085s I have and theres little problem with finding static rams and Eprom (and EEprom) that can keep up. I say little problem as I can find plenty of parts that way too fast in non-DIP formats. If I need faster I can easily find CMOS static rams in the under 25ns range (486dx used 32kx8 and even 64kx8 15ns parts for cache) and larger EE/Flash/Eproms in the sub100ns range. Even back in 1982 I could get power hungry 2147(4Kx1) and 2167(16kx1) parts in the 45ns range. Drams even first out 4164s were under Tcy of 300ns. Old Eproms in the pre8K sizes (2716, 2732) were never fast but 27C256s that do 150ns are really old parts and 27C010s I have are 150ns for the slow parts. Zilog peripherals can be found still at 4mhz and the 8085/8088 (82xx) parts were good to 5mhz with later ones (82Cxx) good to 125ns. Allison >> Cheers, >> Chuck > >

17 years, 5 months

8
15
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Windoze reqs

by dm561＠torfree.net

Message: 16 Date: Wed, 21 Nov 2007 18:23:49 -0500 From: Sridhar Ayengar <ploopster at gmail.com> Subject: Re: Windoze reqs To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Message-ID: <4744BE05.3090903 at gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Fred Cisin wrote: >>> There was Win3.0 (prolly same requirements) >> 3.00 would (and did) run on 8088. One of the font editors that I used >Not only that, it worked properly with a CGA. >Peace... Sridhar -------- And the much higher def monochrome graphics cards commonly installed in the clones (no colour of course). m

17 years, 5 months

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*updating* 8088's

by chrism3667＠yahoo.com

We've all seen different varieties of 8088 to 80286 upgrades. A few at least plug into the 8088's socket. I saw a '286 to '486 upgrade (must have been similar in that respect) at a show a while back (didn't buy it). We also know about OverDrive products. What would happen if you pig-piled all these things in an old 8088 machines? What would happen? Cataclysmic explosion? Were there ever 8086 to 80286 upgrades for the few machines that used them? ____________________________________________________________________________________ Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs

17 years, 5 months

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VAXmate for Windows

by ajp166＠bellatlantic.net

> >Subject: Re: VAXmate for Windows > From: Adrian Graham <witchy at binarydinosaurs.co.uk> > Date: Mon, 19 Nov 2007 12:51:54 +0000 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 19/11/07 06:54, "Zane H. Healy" <healyzh at aracnet.com> wrote: > >> At 9:23 PM -0800 11/18/07, David Griffith wrote: >>> I have seven 5.25" floppies labeled as RX33K which contain: >>> >>> VAXmate MS-Windows v1.03 (two disks) >>> VAXmate Info System v1.1 >>> VT240 Emulator Update >>> VAXmate S/A Install v1.1 >>> VAXmate MS-DOS v3.10 >>> >>> All of these are labeled "For VAXmate operating environment v1.1". >>> >>> I don't remember where it came from, but there's been some recent talk >>> about VAXen. Who wants these? >> >> I assume these will only run on a VAXmate? I've only seen one >> VAXmate and that was nearly 10 years ago. How good was the VT240 >> emulation? > >I never tried the full graphics side of things on the emulator, but as a >terminal it was great, a novelty in those days to have a black-on-amber >display too! > >We have 2 VAXmates at Bletchley Park so if those floppies could wing their >way across the pond that'd be great! I keep meaning to drag them out of >their storage room and set at least one up to exhibit, we're building an >Electronic Office exhibit that the VAXmate should be a part of really. If the VAXmates have the optional hard disk box mind the cooling if RD32 (ST250? 40mb) as it ran very hot and tended to fail. The RD31 (st225 20mb) was lower power, cooler and far more reliable. If you make it operational the VAXmate was a PCSA(Pathworks) terminal with Ethernet access to shared and private files on VAX/OpenVMS. The result made it a very useful system. Typical VAXmate had 2MB of ram some had 4, back then that was a large amount. Allison >-- >Adrian/Witchy >Binary Dinosaurs creator/curator >Www.binarydinosaurs.co.uk - the UK's biggest private home computer >collection? >

17 years, 5 months

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Apology

by dm561＠torfree.net

I've been chastised off-list for forgetting to change the subject header on a few recent posts from its digest default; for anyone else whom I've inconvenienced, my apologies and I'll be more careful in future. mike

17 years, 5 months

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Teaching kids about computers...

by compoobah＠valleyimplants.com

Perhaps not right now, but the biggest "leap forward" I had from books was looking at the 8080/Z80 microcomputer design and operation books (such as Ciarcia's "How to Build Your Own Z-80 Computer" and "Microcomputers and Microprocessors" (8080, 8085 and Z-80) from the hardware standpoint. Probably not a good book until Junior High or High School, though. When I was learning S/W, I remember starting with Logo in 4th grade and using Brainpower ChipWits at home. the ChipWits manual had a small section on programming theory, perhaps I can find it. That's a good game if you have an older Macintosh around (I had issues on machines with over 1MB of RAM - it was written for the 128K, 512K and XL per the disk. Some other people don't seem to have the issues, perhaps there was a revision). In middle school we moved on to BASIC (because it was in the ROMs of Apples). Perhaps not the ideal progression, but nowadays students in the elementary schools don't seem to be learning programming at all- it's more "how you use application software on the computer". In the early '90s Macworld had a 3-part article on how computers work that wasn't too in depth. If you want I can find it and scan it., but it's probably not too much more in depth than David Macaulay's "The Way Things Work" in the new edition. (actually it is)

17 years, 5 months

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test-drb November 2007