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
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
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.
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
> 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
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
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
> 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
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