August 2017 - vcf-midatlantic

Fake 7400-series memory
by Herb Johnson 24 Aug '17

24 Aug '17

> That was a rather interesting read. It's like a combination > of archeology and technology. - Joe Oprysko Right. That's what early vintage computing looks like - kinda. ;) Editorial follows, for those interested. Otherwise: thanks for this glimpse into a corner of chip-collecting. - H Doing some Web "archeology" found the originator of the decapitated chip. It's part of a recent project by Robert Baruch which he calls "Project 54/74" and hosted on YouTube and a wiki at project5474.org, and his Twitter account. He extracts chip die from original 7400 (and the industrial/military version 5400) logic chips, for annotation and imaging; then reverse engineers the schematic. He seems to be doing other vintage-computing stuff as well, with new S-100 boards and 3D printing, very 21st century. Tracing out chip-die sounds like rocket-science; but it's a matter of knowledge and tedium, recognizing visual patterns and following the likely logic. That's what the "fake" poster Ken Shirriff performed in his deconstruction Web post. TTL gate-level logic is usually described in 7400 documents, but not in detail. EE's in the 70's era (like me) were trained in semiconductors at almost the die level; the detailed knowledge is/was available in other textbooks for IC design specialists. And, it's something done in the microprocessor collecting world; tracing out early CPU dies. There may well be other such projects, for other chips including TTL. And it was professionally done in the era as literal reverse-engineering; competitors looking for ways to produce copies, learn design techniques, and so on. "Archeology and technology" overlap considerably; archeologists try to reverse engineer how structures or tools, homes, weapons were made. To me this is another example of what I call preservation by restoration and repair and Web publishing. I work at the S-100 board and chip level, not at the die level. As do others in this email list. Herb Johnson -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net

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Fake 7400-series memory
by Evan Koblentz 24 Aug '17

24 Aug '17

http://www.righto.com/2017/08/inside-fake-ram-chip-i-found-something.html

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FS: Prototype Glitch Works Ohio Scientific Universal RAM Board
by systems_glitch 23 Aug '17

23 Aug '17

link: http://www.ebay.com/itm/272817996082 I'm selling some of the prototype boards for my GW-OSI-RAM1 Universal 128 KW RAM board. This board provides up to 128 KW (64 KW without memory management) of static RAM on the Ohio Scientific bus. It supports a 12-bit word size and is compatible with the Ohio Scientific 560Z "Processor Lab" in PDP-8 mode. It also includes a prototyping area, and a header for mezzanine display boards. Included with the auction is a Hex Lamp Register and an Octal Lamp Register, which can be mounted directly to the GW-OSI-RAM1 or used remote on a cable (e.g. for a front panel). This is a pre-production board, the most significant difference is that it lacks a corner mounting hole, which can be drilled if needed (no circuit traces run under its location). The other differences are minor. See auction link for full description! Thanks, Jonathan

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OT: my own Pi
by Evan Koblentz 22 Aug '17

22 Aug '17

Successfully booted my Pi Zero W into Raspbian tonight. Connected it to my living room TV (native HDMI) plus a keyboard and mouse. Now what? It's a little Linux computer.... although Corey says I shouldn't think of it that way. No need to serve tablet content at home :) so I could use (real) ideas about what to do with it. ________________________________ Evan Koblentz, director Vintage Computer Federation a 501(c)(3) educational non-profit evan(a)vcfed.org (646) 546-9999 www.vcfed.org facebook.com/vcfederation twitter.com/vcfederation instagram.com/vcfederation

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Monitor needed for museum
by Evan Koblentz 21 Aug '17

21 Aug '17

Everyone, We need an HDMI monitor for a permanent connection to the Pi that powers our tablet content. Ideally it should be smaller than 19" (so it can fit on a rack shelf) but not less than, say, 15" (so we can actually read it). I tried using a known-working HDMI-VGA adapter. But it's not supported by the Pi. Does anyone have a suitable screen to donate, or can someone buy it for us? This is something we need quickly. ________________________ Evan Koblentz, director Vintage Computer Federation A 501(c)(3) educational non-profit Evan(a)vcfed.org +1 (646) 546-9999 www.vcfed.org facebook.com/vcfederation instagram.com/vcfederation twitter.com/vcfederation

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OT: Pi RCA conversion
by Evan Koblentz 21 Aug '17

21 Aug '17

I'm reading this: https://www.modmypi.com/blog/how-to-add-an-rca-tv-connector-to-a-raspberry-… I cut one end off a generic yellow-tipped RCA wire and stripped back the insulation. Insider there's one insulated wire (yellow) and one bare copper wire. Which is the positive/negative? Rest assured, I'm experimenting on my own Pi, not the museum's. :) ________________________________ Evan Koblentz, director Vintage Computer Federation a 501(c)(3) educational non-profit evan(a)vcfed.org (646) 546-9999 www.vcfed.org facebook.com/vcfederation twitter.com/vcfederation instagram.com/vcfederation

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Re: [vcf-midatlantic] OT: Pi RCA conversion
by Evan Koblentz 21 Aug '17

21 Aug '17

> Center conductor is video. > Shield is ground. Some would call it negative. Thanks! Found it on Google but I appreciate the confirmation from someone I know and trust.

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Halt and Catch Fire
by John Heritage 21 Aug '17

21 Aug '17

Is the show messing with us? A Sparc station running Excel? :)

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Re: [vcf-midatlantic] Halt and Catch Fire
by Michael Thompson 21 Aug '17

21 Aug '17

> > Date: Sun, 20 Aug 2017 19:32:53 -0400 > From: John Heritage <john.heritage(a)gmail.com> > To: vcf-midatlantic > <vcf-midatlantic(a)lists.vintagecomputerfederation.org> > Subject: [vcf-midatlantic] Halt and Catch Fire > > Is the show messing with us? A Sparc station running Excel? :) > > Sun did have the WABI (Windows Application Binary Interface) that would let you run some Windows binaries. They also had a 386 processor on an S-Bus board that could run Windows. -- Michael Thompson

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An amazing event to photograph
by Ian Primus 21 Aug '17

21 Aug '17

I managed to get a pretty decent photo of the partial Eclipse blocking out most of the Sun. http://i.imgur.com/HqKSde6.jpg How'd everyone else do? -Ian

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