test-drb December 2007

test-drb@ccmp.vtda.org

215 participants
420 discussions

Shift Registers as Delay Lines (was Delay lines in TV sets)

by RodSmallwood＠mail.ediconsulting.co.uk

I actually worked on VDU's that used shift registers as the display memory around 1973. If I remember correctly one lines worth (80 characters) got transferred to a buffer in the interline gap (Fly back time). The buffer was scanned out in such a way as to address the character generator one row at a time. Characters were 7x5 dots so the top five dots of the first character was serialized followed by the top row of the second one and so on. Then all of the second character row dots on a line would be displayed until the end of the store (and therefore frame was reached) New characters would join the tail end (first unused position) of the store as it went past. Rod Smallwood Sitting in my DEC chair in the SUN shine. -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of M H Stein Sent: 18 December 2007 19:28 To: 'cctalk at classiccmp.org' Subject: Shift Registers as Delay Lines (was Delay lines in TV sets) Date: Tue, 18 Dec 2007 10:03:34 +0000 From: Ethan Dicks <ethan.dicks at usap.gov> Subject: Re: Shift Registers as Delay Lines (was Delay lines in TV sets) On Mon, Dec 17, 2007 at 06:52:59PM -0500, Allison wrote: >> MOS shift registers of lengths greater than a few bits are very late >> 60s (after 67 or so). By early 70s parts 1024 long ere not uncommon. >I think I have a couple of old SAD1024 MOS shift registers from when I >was collecting deeply discounted items from the local Radio Shack >"Manager's Table" as a kid. >I had thought one day to make the audio echo/delay circuit I think I >saw in an old Forrest Mims circuit book, but a solid-state acoustic >delay line emulator sounds like a much cooler place to put them. >-ethan ___________ Sounds like our shopping habits were the same in those golden days at the 'shack ;-); I've still got a couple waiting for me to get a round tuit (the data sheet also has the bucket brigade audio delay schematic). As a digital delay line I guess you could even use it word-wise since it's analog; you'd need some pretty fast DAC/ADCs though. mike

16 years, 7 months

Anyone have a Compaq SystemPro?

by steve＠radiorobots.com

Looking for an early Compaq SystemPro for public display. Steve

16 years, 7 months

Homebrew Drum Computer (magnetic heads)

by cclist＠sydex.com

From: Jules Richardson <jules.richardson99 at gmail.com> > Gordon JC Pearce wrote: > > Did any company ever actually produce a storage product that used > > 8-track carts (or indeed broadcast carts)? > > I presume somebody's mentioned Exidy already? (hey, you didn't specify > that the cartridges had to have the correct guts...) Did you perhaps mean Exatron as in "stringy floppy"? Or am I showing my age again? Cheers, Chuck

16 years, 7 months

E: Shift Registers as Delay Lines (was Delay lines in TV

by melamy＠earthlink.net

actually Texas Instruments had a quad 80 bit MOS shift register package available in the early to mid seventies. I had used two of them for a frame buffer on a CRT controller design I did. The part number was TMS3409 I believe and it was something I got from the surplus market. -----Original Message----- >From: Chuck Guzis <cclist at sydex.com> >Sent: Dec 20, 2007 10:40 AM >To: cctalk at classiccmp.org >Subject: E: Shift Registers as Delay Lines (was Delay lines in TV > > From: "Rod Smallwood" <RodSmallwood at mail.ediconsulting.co.uk> > >> I actually worked on VDU's that used shift registers as the display >> memory around 1973.

16 years, 7 months

E: Shift Registers as Delay Lines (was Delay lines in TV

by cclist＠sydex.com

From: "Rod Smallwood" <RodSmallwood at mail.ediconsulting.co.uk> > I actually worked on VDU's that used shift registers as the display > memory around 1973. The Beehive terminal I used around 1975 used an 8008 and a bunch of MOS shift registers for memory. No conventional SRAM/DRAM at all. I recall the parts were small 8-pin DIPs. My 1969 Moto Microelectronics databook shows only a handful of MOS devices: MC1124L - Quad T flip-flop MC1141G - Triple 66-bit dynamic shift register MC1150L - 8 channel MUX switch MC1151L - 2-of-8 channel MUX switch So it's doubtful that MOS shift registers would meet the 1965 criterion at all. Cheers, Chuck

16 years, 7 months

have you seen www.fortran.com?

by cclist＠sydex.com

> From: Chris M <chrism3667 at yahoo.com> > I get the basic jist of what you're saying I guess. > Can you a counter example for clarity? Nope--I'm not going to get nudged for off-topic conversation. Clearly, FORTRAN has nothing to do with vintage computers. > This is going to sound like a stupid question, but > given it's typical applications - scientific and > engineering - why the need for such speed? Oh, atomic bomb explosion simulations, predicting tomorrow's weather, etc. I recall working on a proposal back in the 1970s to supply systems to ECMWF (look it up). One of the fellows I spoke with said something to the effect of: "Golly that's great; now if you could provide us with something about 1000 times faster, we might be able to figure out if it'll rain tomorrow..." > stupid question. Would a modernish pc port lend itself > well to writing some kind of modernish game? > Who else besides the world's worst nerds use it? And > along those lines was COBOL used for anything other > then business apps? I don't know what current implementations of Fortran 2003 are out there for the PC currently, so I can't comment. My last serious involvement with FORTRAN was as an alternate on the F90 (we foolishly called it "FORTRAN 8x" back then. That's optimism for you) vector extensions working group. Talk about some donnybrooks between vendors... I haven't really done anything major with FORTRAN since then and I doubt that I can even understand some of the more exotic aspects of the most modern dialect (F2008 is due out next year). But then, ANSI isn't ANSI anymore--it's INCITS and X3J3 is now just J3. Times change. > Relate to disk archiving? Ok dumb question. Just the basic sector I/O stuff was assembly; all of the logical decipherment was FORTRAN. It made the project go much faster without the verbosity of PL/M. > Oh you don't say. What other languages have reliable, > presumably floating-point capability today? What's gcc > like? Are there cheap Windoze implements? I'm talking about the real hard-bitten mathematicians who run a bunch of data through a vendor's math library and say "Feh--garbage. Let's write our own." I remember commenting about the routines (in FORTRAN, of course) in my just-purchased copy of Cody and Waite to a friend of that persuasion. His face looked about like it would have if I'dve said "You know, the Yugo is really a very fine luxury car." It used to be that the FORTRAN mathlibs at places like Los Alamos and Lawrence Livermore were second to none. Sadly, I don't know if that's true anymore. Sigh...back to assembly for now and cursing idiots who still can't write a decent macro assembler... Back on topic before I'm castigated. Cheers, Chuck

16 years, 7 months

Homebrew Drum Computer architecture

by bnansel＠bigpond.net.au

Thanks for all the great ideas so far! In no particular order: * Delay lines: I have a junk magnetostrictive DL on the way. I don't know if it works. * The idea behind using cassette heads is just to test out my logic and R/W amplifiers at s-l-o-w speed. A baby step. The high-speed stuff would come later. I do have a small lathe (a Taig), so I can handle some of the machining, provided the drum is small (around 4" dia x 9" long). If I can rig a tool-post grinder I might be able to do all of it. * As for the drum coating, it would either be plated with nickel or coated with a mixture of ferric oxide and epoxy. Now for some more questions: I haven't settled on the machine architecture yet. I was thinking a smaller word size would be better because the recirculating registers would have lower latency; that is, a 16-bit word would halve the word time vs. a 32-bit word. Does this make sense? One of the big problems with drum machines is the need to ensure instructions are optimally placed on the drum. To lighten the load a bit I'm considering making it a zero-address stack machine. Then I only have to worry about the occasional random access reads/writes. I was thinking I would implement a data stack and a return stack, each being made of short recirculating buffers to hold the top two or three stack entries, with the older entries swapped to longer buffers with corresponding longer access times. Allowing for the overall insanity level of this project, is this seem a sane strategy? -Bobby

16 years, 7 months

VT-100 emulator

by dave06a＠dunfield.com

I've posted the latest VT-100 emulator to my site: www.classiccmp.org/dunfield It's in the "Download simulators and emulators" section near the end of the main page. There's also a link under the VT-100 entry in "Assorted terminals". I've renamed it to "PC100", which seems more descriptive of it's current functionality. I'm interested in hearing about any VT-100 incompatibilities that you might discover in it, as I'd like to make it as close to 100% as is possible on the PC. Regards, Dave -- dave06a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.classiccmp.org/dunfield/index.html

16 years, 7 months

Homebrew Drum Computer (magnetic heads)

by drb＠msu.edu

> Did any company ever actually produce a storage product that used > 8-track carts (or indeed broadcast carts)? Did it work? There were commercial systems based on VHS decks, good for a couple of GB per tape. Prime actually sold them briefly, iirc. The company I worked for at the time sold a few such systems to our customers, and made them work. I recall video tape quality being critical. De

16 years, 7 months

IBM Bookmanager reader

by mbbrutman-cctalk＠brutman.com

This was a pleasant surprise .. a Java version of the reader for IBM BookManager files: http://www-306.ibm.com/software/applications/office/bkmgr/softcopyread.html It makes some of my old documentation much more accessible. Sadly, it is a 66MB download. (It is also Java code, but requires Windows.) Mike

16 years, 7 months

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test-drb December 2007