test-drb

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101090 discussions

by mtapley＠swri.edu

All, I spotted the following at the Village Thrift Store in Laurel, Maryland (on the north side of 198 about a mile west of the Baltimore-Washington parkway). I was travelling and couldn't pick them up, but one of you may want to take advantage of them. TI-99/4a. In box. The box was bent and crushed a bit but all there. The unit looked to be in good shape. There was packing materials, manuals, power supply, rf modulator, speech synth module. It was the silver version. I didn't test it, but nobody would take that much care with packing everything back up if it weren't working. I think the tag said $12.90. I sort of wish I'd grabbed this. Mac Plus: with KB, no mouse. Security attach point on back. System unit powered up nominally, but I just tested the main unit, not the KB (no boot floppy, no HD). PS/2 looking thing but narrower and with a montor attached. Didn't look at this much. Assorted 386 etc. boxes. Hope that helps someone! - Mark

27 years, 10 months

PC cassette port info

by rhblake＠bigfoot.com

Someone out there had the technical reference for the original IBM PC model 5150. I need the pinout for the cassette port if possible. TIA Russ Blakeman Harned, KY

27 years, 10 months

8088 for free (well kinda)!

by ArfonRG＠allSPAMERSmustDIE.Texas.net

Hey, I have a Hyundai Super 16 computer (no keyboard or monitor) that I need to get rid of. It has an 8088 Processor, an MFM? 5.25 floppy, a full height hard disc, a disc controller card (8-bit), an EGA? video adapter and a dirty case. I hate to waste something that someone else might be able to use so, if you want it email me at: arfonrg(a)allSPAMERSmustDIEhorribly.richmond.infi.net (remove the "allSPAMMERS..." stuff). Thanks, Arfon

27 years, 10 months

discrete transistors

by franke＠sbs.de

>< used in the 7000-series computers to SLT (hybrid integrated circuits on >< ceramic substrates, first used in System/360 in 1964). > Yep. > I disagree that a 286 had more raw cpu performance than some of the big > transistor machines. I still remember the BOCES/LIRICS KA10 running some > 300 users. I've never seen a 286 run more than 4. Same applies to IBM > 2060s. It's a thruput problem - if the main CPU has to handle every byte in and out, you're just doomed. Just about calculating (Additions per second etc.) a 286 can catch up. It's more about the I/O concepts and devices. Add a versitale IOC and blockmode operations and you could run dozends of users on a 286. Even when using a clumbsy unix like byte orientated OS. And wehn using applications, specialy designed to be aware and operate in blockmode even a hunded might be possible. Ten years ago I designed a small 286 system to act as a terminal/dial up server running a stand alone aplication and accesing a database/transactionsystem running under SIEMENS BS2000 (an /390 compatible system) - in a testrun we had up to 64 users with an accestime below 1s per full screen, with up to 12 concourent requests, even including the mainframe transaction (needed in about 70% of all requests). And still only a CPU usage of less than 20% on a 6 MHz 80286! To be honest, this system had a little helper - all serial I/O has been handled by an I/O subsystem with one Z80 for each two ports - only if a reciving transmission was completed the 286 had to act - and for sending only the data had to be transmited to the Z80 memory window via DMA. The host connection was based on a 230 kbit serial line also operating in a kind of blockmode, using a HDLC like multiplex protocoll. The neat thing was that the OS was just linear and message driven - no real time and no preemptive multitasking. Everything was just so fast that a cooperative sheme did work out quite well. So don't underestimate the power of a micoprocessor. We just bring them unde a yoke, no 'real' processor ever har to carry. Gruss H. -- Ich denke, also bin ich, also gut HRK

27 years, 10 months

Need Info on DEC 11/84 Board, M8190

by allisonp＠world.std.com

< Hmm... If I'd seen that out of context, I'd have assumed it was 1000 < millifarads, not microfarads. Over here, we'd write that as "1000=B5F" That was the point. the user of uf instead of MFD was late '60s when I started noticing it. It's still sometimes used. < 1000mF =3D 1Farad :-) But I know what you mean. I used to have some ol < 50mfd 450V caps --and they were big, in those days. I still do. Actually part of the scaling things of capacitor values is related to the way they are used and the math for RF circuits. Also caps are generally two significant digits just like resistors and that is related to the common 20% tolerance applied to them (10% for resistors). I was more used to using number like 10^6 (megahertz) and 10^-12 pF from my RF days. < Err, I think there's an extra "0" in there somewhere, Allison :-) Damm, he lied. Actualy just a dumb typo. ;) Allison

27 years, 10 months

Need Info on DEC 11/84 Board, M8190

by pete＠dunnington.u-net.com

On Oct 18, 21:17, Allison J Parent wrote: > Subject: Re: Need Info on DEC 11/84 Board, M8190 > < But this doesn't explain why some units are not common even in scientifi > < fields. Like the millifarad, for example. > > This is because that is an odd size 1000mF (10^-6) is rather uncommon Hmm... If I'd seen that out of context, I'd have assumed it was 1000 millifarads, not microfarads. Over here, we'd write that as "1000?F" (if using ISO 8859-1 or Unicode character set) or possibly "1000uF" ("u" being the ASCII character that looks most like "mu") or possibly even "1000mfd" (often found on old circuits). > when standard values and notation came about. Back then a 50mF cap was > a large value! It was the advent of transistor circuits and their lower > voltage power supplies that 1000mF were common. Then again we see caps > now in the full Farad sizes. 1000mF = 1Farad :-) But I know what you mean. I used to have some old 50mfd 450V caps --and they were big, in those days. > Then again from a womans point of view, it may be that 1400mm sounds > bigger than 5 and a half inches. ;) Err, I think there's an extra "0" in there somewhere, Allison :-) -- Pete Peter Turnbull Dept. of Computer Science University of York

27 years, 10 months

Need Info on DEC 11/84 Board, M8190/thread drift

by allisonp＠world.std.com

< bit small! Nothing on the scale of the Pentium II has ever been < achieved with transistors, never mind relays, and I'm sure they < tried. For example, it would be possible to place transistors at < 1 per cubic inch, and have the cool adequately, but it's clearly Your unaware of many systems of the 60s that were large on performance and transistors. Your one transistor per cubic inch is far to low. I've worked with cordwood modules that were more in the 6 per cubic inch. Even flat boards were fairly dense. What is missed if the PII uses transistors where other logic systems would employ resistors, capacitors and pulse transformers. Also CMOS requires two transistors to do what can often be done with one using alternate forms of logic. What would be hard to attain is the extreme speeds and that is limited by incterconnections. Putting a few or alot of transistors on one die is not a speed matter in itself. The shrinking of the interconnectivity IE: shorter wires is! When machines got to the Cray speeds the length of wires was an issue as electrons propagate at 1ns a foot. To put that in perspective a PII running at 333mhz is clocking at 3ns! Distributing high speed signals around computers is an art, still. < never been attempted, because if it were, there would be boxes < to plug into a PC XT to get Pentium II speeds. The XT bus and IO are slow, even using a PII would be slowed. BEsides it was done using 386s... Allison

27 years, 10 months

COMPUTER SPACE REGISTRY

by altair8800＠hotmail.com

Van, You may get a good response if you also post your request to the newsgroup <rec.games.video.arcade.collecting>. Bob Wood ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com

27 years, 10 months

Need Info on DEC 11/84 Board, M8190

by dburrows＠netpath.net

>< I believe that "mmg" is still used as a prefix in medical fields, >< but here it means (as far as I can figure out) "millimicrogram". >< Can someone correct me on this (I'm sure I'm wrong!) > >A friend is a toxicologist and with it isn't PPM it's picograms/liter. > In the environmental testing field PPM, PPB and PPQ for part per quadrillion are standard. Also nanogram, picogram and even femtogram are standard terms for Mass spec. injection amounts. Current Mass spec. detection limits are in the VERY low femtogram quantities. Dan Burrows dburrows(a)netpath.net

27 years, 10 months

VCF on CNET

by jimw＠agora.rdrop.com

At 02:57 PM 10/18/98 -0700, you wrote: > >Yah! The Vintage Computer Festival was immortalized on television. > >It aired on CNET Central on the USA network this morning at 6:00am. You >might be able to catch re-runs of it this week on local stations. Its the >last segment of the show. > <snippage> ...also, (tho I have not seen the segment yet) CNET placed links to the VCF website and my Computer Garage web site on the CNET Central site. (don't know if the sites were specifically mentioned in the segment) But, a LOT of people have been watching, at least if I can guage anything by the number of emails I have received since yesterday mentioning the CNET segment. I suspect that I'm going to be referring a number of these people to the list, since nearly every one of them has been asking about new homes for old gear! (after I cull out the neat ones of course... B^} ) Overall... COOL! -jim --- jimw(a)agora.rdrop.com The Computer Garage - http://www.rdrop.com/~jimw Computer Garage Fax - (503) 646-0174

27 years, 10 months

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