test-drb

test-drb@ccmp.vtda.org

101090 discussions

by CLASSICCMP＠timaxp.trailing-edge.com

>> What you find "bizarre" is almost certainly what I like about them. 12-, >> 13-, and 14-bit wide instruction words, Harvard architecture so that >You've been using them for quite a while if you remember the 13-bit ones. :-) >IIRC, that was the PIC1670 (not PIC16C70!); perhaps there were some other >13-bitters. That was before I started with PICs, though I have the old data >books around here somewhere. I was using them when they weren't even called PIC's, and were sold by General Instruments... -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology Voice: 301-767-5917 7328 Bradley Blvd Fax: 301-767-5927 Bethesda, MD, USA 20817

27 years, 11 months

Homebrewing a classic

by cmcmanis＠freegate.com

Some thoughts on this homebrew stuff... Front Panels: ------------- I've been mulling over the idea of building a "generic" front panel. Clearly there is a lot of resonance with the blinking lights of the PDP-series, the Altairs and IMSAIs etc. However if I did this it would have to be both durable and cheap. Having rebuilt a couple of PDP-8 KC8's I think the rocker over the slide switch can be cheap but it isn't durable. I've been sketching ideas based on a rocker that is threaded on a rod. The back of the rocker contains a 'paddle' which when the rocker is down, breaks an IR/detector gap. This has a couple of benefits. One the rockers are on a rod so they don't have small pins to break off, and two the switch mechanism is optical and thus not subject to oxidation decay that mechanical systems suffer. Of course I would like the front panel to be usable for a variety of hardware designs and that leaves open the question of 'generic' switches. Clearly there are the following switch requirements: Run/Stop Single Step - momentary Deposit - momentary Examine - momentary Load Address - momentary switch register - what size? Could have 8 to 32 bits if we wanted Key switch - Off/On/Panel Lock Some panels adopted a dual action switch for 'examine'/'examine next' and 'deposit'/'deposit next'. Clearly that's harder to do with my simple optical switch. Compound Computers ------------------ I've about half decided to build something PDP-8 like out of PIC chips. They are relatively cheap, easy to program, and quite fast. I hadn't thought about using them as base units (microcode sequencer, ALU control, etc) until this discussion began, but it also raised the point of 'emulators' and I began to wonder what if you build a Z80 system that emulated a PDP-8 with one of these custom front panels. That turns out to be more of a software effort than a hardware effort. Transistor based CPUs ---------------------- You can get PC boards made fairly cheaply, if you wanted to do a transistor based CPU I would definitely consider having a few hundred 'flip chip' equivalents made. It wouldn't have to be 1:1 DEC replacements but they showed it could be done. Wiring up 12 flip flops by hand on a piece of perf board (4 transistors each!) would be extremely painful. TTL Logic based CPUs -------------------- First, find a 50Amp 5 volt supply. :-) The thing about TTL logic that always amazes me is how much power it draws. I built a digital PLL out of TTL chips once (about 40 chips) it was easily drawing 3-4 amps at speed. 74HC logic might be a good compromise here. The use of CRTs --------------- There is a really clever homebrew display that was influenced by early computers called the 'beer budget graphics display' and was featured in BYTE magazine in the late 70's. Basically this was two R2R D/A ladders driving the X/Y inputs to an oscilloscope. If you make a 12 bit machine you could build a 4K x 4K resolution display fairly easily. (You will be core limited in terms of points to plot but what the heck right?) This type of output was featured in several different early computers. Anyway, just some thoughts... --Chuck

27 years, 11 months

Working PDP-10 anyone?

by dastar＠ncal.verio.com

Does anyone know off-hand where there might be a complete, working PDP-10 system? Sam Alternate e-mail: dastar(a)siconic.com ------------------------------------------------------------------------------- Ever onward. Coming in 1999: Vintage Computer Festival 3.0 See http://www.vintage.org/vcf for details! [Last web site update: 09/21/98]

27 years, 11 months

Somebody has a C65 on eBay

by jeff.kaneko＠juno.com

SUch crazy people. I think I will re-organize the Governor William J. Le Petomane Gambling Casino for the Insane (formerly the La Petomane Asylum for the Insane) and re-open this establishment as the Governor William J. LaPetomaine Computer Store for the Insane! A new era of lunacy is just on the horizon for the insane computer collector . . . . {Tongue removed from Cheek} On Mon, 5 Oct 1998 11:04:41 -0700 (PDT) Cameron Kaiser <ckaiser(a)oa.ptloma.edu> writes: >:: >::Somebody's posted a Commodore C65 prototype on eBay. 4 days left >and the >::bidding is at $1025. >:: > >That's nothing. The last one sold went for $1400. (!) > >-- >-------------------------- personal page: >http://calvin.ptloma.edu/~spectre/ -- >Cameron Kaiser Information Technology Services Database >Programmer >Point Loma Nazarene University Fax: +1 619 >849 2581 >ckaiser(a)ptloma.edu Phone: +1 619 >849 2539 >-- Jesus at a disco: "Help! I've risen and I can't get down!" >----------------- > ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com or call Juno at (800) 654-JUNO [654-5866]

27 years, 11 months

Internet software for an XT computer

by lfb107＠psu.edu

At 09:24 AM 10/5/98 -0500, Kirk Scott wrote: > > >On Sun, 4 Oct 1998, Phil Clayton wrote: > >> I'm sure I have read before that some users on the forum use internet >> software for accessing the internet that will run on old XT running DOS >> (Text only)..? >> Would someone tell me where I could get a copy of this software.. >> Thanks.. >> Phil... > >Phil: > >The program you want is "Nettamer" and you can get it from garbo.uwasa.fi >in the /pc/connect/ directory; filename: n1101xt.zip > >It's great, it was the first program I used to surf the 'Net on my XT! > >Kirk Scott You might also want to check into something called Arachne. Although it lists a 386 as a "minimum," the docs say it should run on any x86 with an EGA or VGA card. BTW, Arachne is basically a graphical web browser with (i think) ppp or slip buillt in. (Runs under DOS too) Les

27 years, 11 months

Universal drive

by maxeskin＠hotmail.com

OK, next question. While I look for weird expansion cards, is there any book that I stand a chance at finding which details the DOS flopy format? >> Hmmm... I don't know of one built commercially, but how about a board >> based round an FPGA (for the non-hardware types, basically a configurable >> chip that you can make just about any logic circuit out of) linked to an >> floppy drive. Oh, and some kind of programmable clock (I don't think >> dividing down a master clock with the FPGA would really do it)/PLL thingy >> to act as a read clock. > >Overly complicated, no (hardware) PLL necessary. Just sample the data from >the drive at a sufficient multiple of the channel code data rate (8x should be >plenty), and do the data separation in software. That way it really is >completely independent of the data format. That's the way I designed my >closed-caption decoder (5x), and it works quite well. > >Note that this doesn't deal with all of the weird Apple ][ copy protection >schemes (like spiral tracks), but it will deal with some of them. > >I have a twiggy disks for the Lisa 1 with a bad sector. I've always wondered >whether hacking the drive electronics to allow software control over the >read amplifier gain and/or data slice threshold would let me recover that >sector. > >Cheers, >Eric > > ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com

27 years, 11 months

CRASH!!!

by aaron＠wfi-inc.com

My mailer crashed and I lost some addresses. A few days ago I asked if anyone needed a 486DX/2 66 chip...uh...if you responded then, please email me again. There were three responses, and I remember that the third one was Uncle Rodger. Sorry for the inconvenience, guys. Aaron

27 years, 11 months

Qbus card info needed...

by aaron＠wfi-inc.com

Hi all, I got a Plessey PDP-11 clone from John Lawson today and was just poking around at the cards. I thought I'd check to see if anyone had any info on some of the non-DEC stuff in there: 1. Peritek, video board, "VIURAM VRG-Q11" - there is a cable plugged into the 10-pin connector on this one, which ends in a single BNC plug. What kind of video does this output? Any ideas on what kind of display I could use? 2. Plessey, memory, p/n M8044DK and p/n M 8044 DB 3. Plessey, multifunction p/n PM-MFV11A 4. Standard Memories, ???, MM-148 - this board has 4 rows of MCM6665 64k rams and a toggle switch on the handle edge. There are two led's, one labeled "PWR OFF" and one labeled "ON RUN." There is also an 8-position DIP switch toward the connector side. Thanks in advance, Aaron

27 years, 11 months

PDP-9

by cmcmanis＠freegate.com

Better get a small truck... http://pc.dec-j.co.jp/support/may/dec_jpg/part_1/image/pdp9.jpg At 04:56 PM 10/1/98 -0500, you wrote: >I just talked to somebody that has a PDP-9 that has been in continuous use >(24 hours/day) since 1967! They're finally thinking about phasing it out. >So, I was thinking.... How big is a PDP-9? > >-- Doug >

27 years, 11 months

Textronix 4025 terminal seen

by mtapley＠swri.edu

All, Spotted a (what I regard as) classic terminal the other day. It was at A-Tex electronics in San Antonio (if your phone book isn't that new, call the Altex electronics and ask for their recently spun-off parts division near the airpont). It was not in good shape - several keycaps broken off, scratched, very dirty, no manual. It was $25 as is, and I had no chance to power up and see how it is. Also the missing manual hurts, because a lot of the very cool and well-thought-out graphics instructions are called by escape sequences that I don't remember at all. If I remember right, the 4025 was Tek's start at transitioning off the long-lasting phosphor technology into a regular bit-mapped display. Istr that it had maybe 2 Z-80's and about 64k of RAM, which was not bad at the time (late 70's to 1980 or so?) for a whole system, to say nothing of a terminal. It had a pair of thumbwheels for cursor control. It felt and looked industrial strength and was a pleasure to use. Anybody remember more useful info about it? - Mark

27 years, 11 months

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb