test-drb

test-drb@ccmp.vtda.org

101090 discussions

by mark＠markesystems.com

Allison wrote; >I envy the chance to restore a LGP-30 or for that fact play with one. >Many of the things I remember >mid sixties on are now gone or were rare then. Like small desk sized drum >computers using transistors or first generation IC (RTL and RDTL). Rick Bensene wrote: >I so regret not having rescued an old computer that I played with through >all four years of high school. >The machine was made by Minnesota Mining and Manufacturing (aka 3M >Corporation). Today, there seems to be no record that 3M ever was in the >computer business. But...it was. I never saw one of those, but the computer center I worked at in college dumped a Cincinnati Milachron small business computer system - *not* a machine tool controller. I tried to grab it, but that was not to be. Same thing - there's no record anywhere I could find that they were ever in that business. <...> > along with another old machine that was donated to the school...hardly a > computer, more like an accounting machine, made by SCM, called a 7816 > Typetronic. I actually ended up with a complete SCM 7816 system, including: - The I/O Printer, which was a hacked SCM electric typewriter, with diode-matrix encoding for the keyboard, and relay decoding for the printer; it used a row of washers to mechanically ensure that only one key could be pressed at once. It also had a paper tape reader built into the back of the carriage, so that some computation could be triggered by the carriage position, or performed while the carriage was returning. - The main 2816 control unit, with a plug-board "output panel" to route data between the various peripherals; this also had the massive power supply, which used a ferro-resonant transformer to regulate all of the voltages. - The optional (!) 7816 arithmetic processor, which did bit-serial addition, subtraction, or multiplication (no division, but this was simulated by using reciprocal multiplication); there were nine 10-digit registers (no other working memory), all implemented on a fixed-head disk, plus a buffer implemented electronically. Add time was 17ms, multiplication 700ms; this is why the ability to do calculations during the carriage return was valuable. - Two paper tape punches - these were re-branded CDC punches, and were very nice units. 40 characters per second, with a built-in automatic verification; they could also be used to punch on the side of cards, instead of tape. - Two paper tape readers. These were built by SCM, and were pretty nice too; they were optical, would read at 30 characters per second, and could stop from full speed on the next character. - The custom desks, which included a recess for the I/O Printer to sit in, and acted as chasses for the 2816 and 7816. - All of the manuals and schematics for the whole thing. Some of the logic was made using thick-film modules, but most was on the vintage single-sided boards, with obviously hand-drawn traces and jumpers on the component side. Somebody has uploaded some of the manuals and 2816 schematics to bitsavers, but not the schematics for the 7816. With the complete schematics, I was eventually able to get the thing to type and read and punch tape, but I never got the arithmetic unit working. That machine was *really* dumb... I carted the whole thing around for about 15 years, until the new wife decided that she was more important than the space it consumed. That's OK, I guess - I eventually ended up dumping her, too... ~~ Mark Moulding

9 years, 1 month

Friden Auxiliary Reader

by kylevowen＠gmail.com

I guess I'm on a roll, trying to find out what some things are in the collection. Any idea what this paper tape reader could've been connected to? http://imgur.com/a/DjRj7 Thanks, Kyle

9 years, 1 month

Vintage computer keyboards, computers, and other stuff

by sales＠elecplus.com

Some is not so vintage, but most of it is. https://elecshopper.com Yes, I will ship internationally, but the value on the customs forms will reflect the actual price paid, as do the invoices. Look around, maybe find something interesting. The RSS feeds are at https://elecshopper.com/RSS if you want to keep an eye on new additions, sales, etc. More products are usually added every day. Cindy Croxton Electronics Plus 1613 Water Street Kerrville, TX 78028 830-370-3239 cell sales at elecplus.com AOL IM elcpls

9 years, 1 month

Homebrew Z80

by vintagecomputer＠bettercomputing.net

You might be looking at my TVT project.. sorry. ?The z80 computer is mixed in there. ?Here's a direct shot of its motherboard: https://drive.google.com/file/d/0B4pq0-BHd2x6WmVQZjctMzFadlk/view?usp=drive… Sent from my Samsung device -------- Original message -------- From: Liam Proven <lproven at gmail.com> Date: 2017-01-07 6:37 AM (GMT-08:00) To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Subject: Re: Homebrew Z80 On 6 January 2017 at 20:52, Brad H <vintagecomputer at bettercomputing.net> wrote: > > > I've put some pics of it here: > https://drive.google.com/drive/folders/0B4pq0-BHd2x6bjY3MTRZbGRCQmM?usp=shar > ing > > > > Thoughts/opinions welcome. The logo is right there on one of the boards. http://www.swtpc.com/mholley/RadioElectronics/TV_Typewriter.htm https://en.wikipedia.org/wiki/TV_Typewriter -- Liam Proven ? Profile: https://about.me/liamproven Email: lproven at cix.co.uk ? Google Mail/Talk/Plus: lproven at gmail.com Twitter/Facebook/Flickr: lproven ? Skype/LinkedIn/AIM/Yahoo: liamproven UK: +44 7939-087884 ? ?R/WhatsApp/Telegram/Signal: +420 702 829 053

9 years, 1 month

Homebrew Z80

by vintagecomputer＠bettercomputing.net

Hey guys.. I bought this Homebrew Z80 machine from what I assume is the early 80s (going by the chips). Pretty sure it's a Netronics keyboard but wondering if any of you have seen a design like this one. I'm just curious if it came from a magazine article or something as it goes beyond the typical basic homebrew and even appears to have some ROMs. I'm not sure what the TOS ROM is though. I've put some pics of it here: https://drive.google.com/drive/folders/0B4pq0-BHd2x6bjY3MTRZbGRCQmM?usp=shar ing Thoughts/opinions welcome.

9 years, 1 month

Does anybody have a KIM-1 for sale?

by r3trohub＠gmail.com

Hi all! Wishing you all a happy new year :) I'm looking for a KIM-1 system and/or any other related hardware, the earlier the better! If you have one you'd like to sell, please drop me a line :) -A

9 years, 1 month

Morrow MD-3P Portable MicroDecision

by aek＠bitsavers.org

www.ebay.com/itm/302178528335 bought for the CHM collection. This is the first one I've ever seen. I don't remember if the Morrow sons auctioned one off when they were selling off George's shop. It's essentially a MicroDecision III and MT-70 terminal according to the notes I scanned.

9 years, 1 month

Boot Loader for 3P+S on IMSAI

by wheagy＠gmail.com

I have an IMSAI that I am restoring. The basics appear to be working (front panel, CPU and RAM cards). I have a Processor Tech, 3P+S card that is next on the list for testing. I have the manual, but the card was not configured for RS-232...not sure what it was configured for but it doesn't match anything in the manual. I plan to reconfigure it for RS-232. I'm trying to locate boot loader code for that board to allow serial uploading of files from a PC to the IMSAI? I have boot loader code for a 2SIO board on an Altair that I restored awhile back, and would like to find something similar for the 3P+S. I want to be able to toggle in a boot loader routine and then initiate an upload >from the PC to IMSAI -- something similar to this https://www.youtube.com/watch?v=YwC1T9oLK1U&t=212s (at 1:10s in) but with a 3P+S board on an IMSAI. Also, a picture of your RS-232 configured card and wiring of the edge connectors would be helpful to make sure I get things right. Any help is appreciated. Thanks, Win wheagy at gmail.com?

9 years, 1 month

Seeking English version of LGP-30 Maintenance Manual

by coryheisterkamp＠gmail.com

Christian Corti had made available the German version of the LGP-30 Maintenance Manual, copied here: http://ed-thelen.org/comp-hist/LGP-30MaintenanceManual-German.pdf Ed Thelen had OCR?d and translated some of the pages, but I?m looking for a copy of the complete English version if someone has it available. A search of the CBI archives didn?t turn up anything, either. If only paper copies exist, I would be glad to pay postage, scan, and send back the manual if someone out there has it. Thanks- Cory

9 years, 1 month

cctech Digest, Vol 30, Issue 15

by tim＠tim-mann.org

For what it's worth, xtrs (http://tim-mann.org/xtrs.html) emulates LD A,R by putting an 8-bit random number in A. Of course that's cheesy and wrong -- especially bit 7 being random instead of retaining a 0 from reset or the last value written to it -- but at least it works OK with Ethan's subroutine. The subroutine may loop a few times due to the value randomly being negative or zero until it escapes the first time the value is randomly positive. xtrs sets the sign and zero flags according to the value, and does something complicated with the other flags that I don't remember the reason for -- but it might be correct; i think I got it from some reference on the web last time I hacked on that instruction. The pointer that someone posted to http://www.worldofspectrum.org/faq/reference/z80reference.htm#RRegister may inspire me to fix the emulation, though it looks like a bit of work to get it exactly right... On Thu, Dec 15, 2016 at 10:00 AM, <cctech-request at classiccmp.org> wrote: > Message: 10 > Date: Wed, 14 Dec 2016 17:34:29 -0500 > From: Ethan Dicks <ethan.dicks at gmail.com> > To: "General Discussion: On-Topic Posts" <cctech at classiccmp.org> > Subject: Re: Z-80 code question about a loop that depends on the > contents of the refresh register > Message-ID: > <CAALmimm07Bf=fjp70jzMKiV0m94aWxzggjeZuJg=ji > LeLXT+gw at mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > On Wed, Dec 14, 2016 at 4:26 PM, allison <ajp166 at verizon.net> wrote: > >>> On 14/12/2016 09:19, Ethan Dicks wrote: > >>>> > >>>> So far, this loop hangs on all three emulators I've tried - simh's > >>>> altairz80, simcpm010 for AmigaDOS, and EMUZ80 for Raspberry Pi. I'm > >>>> guessing none of these environments emulate specific behavior of the > >>>> Refresh register? > > > The first year of appearance for 64K DRAMS was mid to late 1980 > (expensive > > and scarce) and mostly sampling to the big vendors. For regular users > late 81 > > when the price started down. > > Right. I was a user of 8-bit micros in that exact era. My first > hands-on experience as a user was the memory inside the Commodore 64. > My first engineering experience was in 1984 on a product designed in > 1983 (COMBOARD-II with 128K of 4164 chips and a 74S409 refresh > controller). > > > There were three flavors, 8bit refresh, 7bit refresh, and > > internal refresh came in a bit later by maybe mid 1982. > > I know there were different types but not those details. Thanks. > > > The Z80 could do 8bit refresh with hardware or software or the self > refresh > > (internal). > > I'm also a little fuzzy on this aspect of things because I was never a > Z-80 user back in the day. > > Software Results considered a Z-80 COMBOARD very early on, but > abandonded that approach because it would have likely required 2 hex > Unibus modules and so opted to hold out a few months and go with a > 68000 and SRAM design on a single hex card (my old boss still has an > XC68000 with S/N 424 engraved on the lid). > > > Nominally the R register is a counter that increments from any value to > 7bit > > overflow. > > So I'm learning. > > > I believe most emulators actually do that. > > The first three emulators I tried (simcpm010, altairz80, and EMUZ80) > on three different platforms (AmigaDOS, Linux, and ARM) do not. I now > have a couple of names of DOS/Windows emulators that should. I will > have to run them under Wine since I'm not a Windows user. > > It's funny because I would have tried this on simcpm010 25 years ago > (it was on the Amiga disk I just extracted all these files from) and > it would have failed then just as it fails today, and then, I had *no* > idea why. I've learned a lot since then because it only took me a few > hours of digging to uncover why. > > > Check MyZ80 Simon Crans work (32bit > > dos/ pre-7-winders only or in a 32bit sim/VM). > > I will look that up. > > > Either that or lookup and assemble Grant Searle's low chip count Z80 > system. > > The worry is not running on real hardware. Once I get some time to > clean up my XOR or dig out a Kaypro, I will run it on real hardware. > I want to find/fix an emulator for modern machines so that other > people can just grab and go. Also, this is not _just_ a Z-80 program, > it's a CP/M program, with CP/M BDOS calls to open/close/read/write > files and read-from/write-to the console (F_OPEN, F_CLOSE, F_READ, > F_WRITE, C_READSTR, C_WRITE). > > Right now, I'm leaning towards fixing altairz80 first since that runs > on "everything". I may also work with the author of EMUZ80 so it > works on bare-metal Raspberry Pi (EMUZ80 is a Pascal app that runs in > the Lazarus bare-metal framework, so you need Windows to rebuild the > app). I don't mind putting known-working Windows-based emulators on > a list of "verified environments", but I'm not going to push this to > the public without a Mac and a Linux answer. Telling the world that > they have to build a real Z-80 CP/M machine to play a game isn't going > to hit a large audience. > > Thanks, > > -ethan >

9 years, 1 month

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test-drb