- vcf-midatlantic - lists.vcfed.org

Re: [vcf-midatlantic] Our new toys :)
by Evan Koblentz 16 Mar '16

16 Mar '16

>> Nameplate for the Univac (special thanks to Corey L.): >> http://vcfed.org/evan/1219face.jpg > > I seem to have missed the beginning of this so sorry if > it was already answered but, is that an original or a > reproduction? Most of the appearance suggests original > but the "1219" looks polished and new. It's an original. A recycling company, in the same area as where our UNIVAC came from, just happened to have all the same parts that ours is missing. That makes me very angry, because it probably means someone took the parts before we got to it and then flipped them for money. Further, when we approached the recycler with our story -- we're a museum, blah blah blah -- they basically said, "Tough (bleep), you want it, you pay our retail price for it." We told them NO and figured we could probably get a reproduction. Later, Corey L. took it upon himself to buy the faceplate so he could donate it to us. :) Now our Univac won't have an identity crisis every time it looks in the mirror.

2 1

(Delayed) pictures from yesterday
by Evan Koblentz 16 Mar '16

16 Mar '16

Here are some pictures of the back half of the new room, in which you can see how the microcomputer exhibit is shaping up: http://vcfed.org/evan/long1.jpg http://vcfed.org/evan/long2.jpg There's a lot more work to do. For example, each station will get a backdrop, so visitors (and their pictures!) are not distracted by artifacts/walls behind the units. We determined that the most affordable way to do this is to use bolts of fabric. A bolt is a yard wide (same as each unit), up to 10 yards long, and can be purchased in almost any color. I called the fabric store and found out they'll even cut an entire bolt into a zillion slices for us. If we get them cut into 6-ft. lengths (same height as each shelving unit, then we can just attach them to the back of each unit, it makes a nice backdrop, and it's completely mobile with the unit itself. The question is, what color should be get? Beige? Off-white? Light gray? Light/medium blue? Note: In the second picture, the iMac + late-90s internet appliances are not part of the micro exhibit; they're part of the modern history exhibit. Will pick up some dark green fabric for its background so it matches the green wall across from it (shown in earlier pictures).

9 13

Re: [vcf-midatlantic] (Delayed) pictures from yesterday
by Brian L. Stuart 15 Mar '16

15 Mar '16

> I would advise caution in the selection of material. If you get something > relatively fine-woven it will be a lot less likely to collect dust, though > relative immunity from static buildup helps there too (and is probably a > good idea anyway, considering the nature of the collection, heh!) I'd also suggest getting a sample and doing some test photography with it. There are some fabrics that flashes go through in such a way that the fabric almost becomes transparent. The photograph of me receiving my bachelor's degree has a really bizzare effect from the cheap rental robe where it appears you can see right through my leg. BLS

4 3

VCF East - sponsors sought
by Evan Koblentz 15 Mar '16

15 Mar '16

Guys, We need more business sponsors for VCF East. If anyone has a specific lead (not a hypothetical one), then please contact me privately. - Evan

1 0

This just in -- Ted Nelson @ VCF East, take two
by Evan Koblentz 15 Mar '16

15 Mar '16

Ted Nelson agreed to be our Sunday morning speaker.

3 2

microvax3100.vintagecomputer.net up today
by william degnan 15 Mar '16

15 Mar '16

microvax3100.vintagecomputer.net is up today, contact me privately if you'd like a user account. I ordered more cables to expand the cluster (to two) using DecNet, but right now it's just stand-alone and available by TCP/IP only email is system(a)microvax3100.vintagecomputer.net, you can telnet to access other services. VMS 5.2 Bill -- @ BillDeg: Web: vintagecomputer.net Twitter: @billdeg <https://twitter.com/billdeg> Youtube: @billdeg <https://www.youtube.com/user/billdeg> Unauthorized Bio <http://www.vintagecomputer.net/readme.cfm>

1 0

microvax3100.vintagecomputer.net
by william degnan 14 Mar '16

14 Mar '16

Hi all...I have microvax3100.vintagecomputer.net up and running today if any club members want to ping, telnet, or email to system(a)microvax3100.vintagecomputer.net. contact me privately for telnet credentials. This weekend I installed MULTINET v 4.1. (VMS 5.3) with the help of Peter Coughlan who helped me locate an install file for multinet. Next I need to pick up another ethernet converter box (CentRECOM 210T) so I can cluster two vax machines. fun. bill -- @ BillDeg: Web: vintagecomputer.net Twitter: @billdeg <https://twitter.com/billdeg> Youtube: @billdeg <https://www.youtube.com/user/billdeg> Unauthorized Bio <http://www.vintagecomputer.net/readme.cfm>

2 2

ISO: Bytek S-10 EPROM Programmer Manual
by Systems Glitch 14 Mar '16

14 Mar '16

Anyone have the manual for a Bytek S-10 standalone EPROM programmer? I just finished repairing the power supply in one, it appears to be functional now, but I don't have the manual. It requires numerical device codes to select your EPROM type. If anyone has it but only in paper form, I'd be happy to pay shipping both ways and scan it with my ADF scanner. Even a list of device numbers would be super helpful! Thanks, Jonathan

1 0

examples of non-crystal based clocks in digital computing?
by Herb Johnson 14 Mar '16

14 Mar '16

> Ben Greenfield posted: > > I have one simple specific question, without a simple answer > and general call for examples. > > I’m researching timing clocks used in general purpose digital > computing. I’m starting to think that Ace/Pilot Ace by Alan Turing > is the start of clock based general purpose computers. I’m starting > to conclude the earlier computers were all basically clocked > by the media holding the instructions. My apologies, but I'm a degreed electrical engineer, who first studied computers as digital logic devices and circuits in the mid-1970's. My response is to refute the premises. I don't think the question is simple or specific. It's kind-of specific, but "timing clocks" and "general purpose computers" are not well defined terms in very old digital computing (since Turing is mentioned). I don't think general examples covering several decades of computing will provide "simple" examples and answers. I have a tough time, figuring out pre-1970's mincomputers (much less pre-1960's mainframes) from my Intel 8080 point of view. Digital computers of decades before, say, computers built from integrated circuits, were of all kinds of designs. They are different in fundamental ways. In particular, some operate under a common timing or clock signal, some do not BUT they may have features that are repetitive. A common clock may be needed or may not. Terms like "synchronous" and "asynchronous" and "sequential", are part of the world of computing theory. Things happening one after another are sequential, but may not be synchronous. Some drum-based computers to my knowledge, included their computing registers *on the drum*. One transistor model of the 1960's I know from ownership, had several copies of its registers on the same tracks - why? For faster access. Was there also a clock signal which was ultimately tied to the drum rotation rate? Have to check the manuals, but the drum did much of the work anyway. As for "general purpose" digital computers - there were all kinds of computers several decades ago, many were specific-purpose. Maybe Ben means "programmable" computers, I dunno. I have little idea about what Ben is looking for. But that's OK, there's nothing wrong with creating some assumptions and premises about ancient computing (digital or otherwise), and seeing what one can learn based on those premises. You have to start with what you know, or think you know. I stumble over my own assumptions all the time. But in my own opinion about retrospective looks at very old computing, there's a problem when one assumes modern designs and architectures as a "standard" and then looks back to see where that "standard" fails or breaks down or when it started. For example: for some reason the thread is talking about crystal-controlled clocks versus not. The question wasn't *exact* clocking. A timing fork in a UNIVAC at 1024 Hertz, "sounds" fine to me. A tuning fork (wikipedia) varies by under 100 parts per million per degree C. But a microprocessor can use a variable clock signal from an R/C circuit and work fine. I run an 1802 microcomputer which sometimes uses an R/C circuit clocking down to audio rates - programs run just fine, not precise in time, but slow (and at very low power consumption, microwatts and milliwatts). I prefer to examine ancient computers on their own merits, look at their features on their own terms and on terms immediately contemporary to their times. As a digital engineer I can compare-and-contrast circuits and learn about benefits and limitations, but only in the context of intended use can one pass judgements. and of course, engineers (and techies) often disagree about such judgements. So: it's an interesting question, when put in a general way: what kinds of ancient (or recent) computers did not depend on a common and well-controlled clock signal to synchronize their operations? and how did some operate without it? But for all I know, Ben is asking when computers "first" used a synchronous clock signal for all its computing circuits (whatever that means). I'm not a big fan of "firsts", in any ranking something is always "first", so what? Herb Johnson vintage computing scold -- Herbert R. Johnson, New Jersey USA http://www.retrotechnology.com OR .net

2 1

Re: [vcf-midatlantic] examples of non-crystal based clocks in digital computing?
by Brian L. Stuart 13 Mar '16

13 Mar '16

On Sun, 3/13/16, Evan Koblentz via vcf-midatlantic <vcf-midatlantic(a)lists.vintagecomputerfederation.org> wrote: >> I’m starting to conclude the earlier computers were all >> basically clocked by the media holding the instructions. Is >> this correct? > > I don’t believe so. ENIAC had a master pulse generator. > > Brian Stuart (on this list) is making his own ENIAC simulator. Thus he'll > have a mich deeper understanding than the rest of us about how the > computer really worked. To follow up on this, one of the 40 racks of the ENIAC is the cycling unit. It's heart is a 100KHz crystal oscillator, but it also has an input and selector switch to be driven from an external oscillator. Every 20 cycles of this main oscillator makes up one addition time and generates a set of 10 clocking signals that are routed around the whole machine to clock all the other units. There's a selector switch to select continuous, one pulse, and one addition modes allowing the operator to single-step either by single cycles of the main oscillator or by single sets of pulses making up one addition time. The cycling unit even has a built-in oscilloscope to display the main clock or any of the 10 signals routed around the machine. IIRC, the cycling unit is one of the units that UPenn has on display in the Moore School building. (Though I may be misremembering and it may be the initiating unit they have.) Generally, if the main storage for the machine was a drum, it made a lot of sense to put the clock on a track or two of the drum and let the drum's motor determine the basic cycle time of the machine. That way you don't have to worry about keeping the internal clock and the drum drive motor synced, and you get your main clock more or less for free. The G-15 we have in the museum works like that. For most other designs, it makes more sense to have a separate clock either based on a crystal or an R/C oscillator. Interestingly, the engineer Harry Huskey was involved with three of the machines mentioned in this discussion, the ENIAC, the Pilot ACE, and the G-15. BLS

1 0