Al has a reader at CHM. They can read tapes too, my 7-track setup is now at System Source.
Paul
> On Sat, 2025-02-15 at 14:52 +0000, Sid Jones via cctalk wrote:
> > IIRC, I have a copy of the Elliot 803 A-103 Algol compiler on a five-
> > hole
> > tape in a drawer somewhere in my untidy office...
> >
> > As used in UCNW Bangor, 1971-1974.
>
> There might be a reader somewhere. If anybody has (or developes) an
> 803B emulator, it would be nice to have the compiler.
>
> Paul Pierce read several IBM 1401 tapes. The Computer History Museum in
> Mountain View, CA has two operating 1401s, and the SimH project has an
> emulator. It's nice to have the Autocoder assembler, FORTRAN II and
> FORTRAN IV compilers, COBOL compiler, ⦠to use. There are students at
> San Jose State University who go to classes in 1401 programming at CHM.
>
> Maybe Paul has a paper tape reader too.
>
>
>
>
https://thisistrue.com/sokol-behind-scenes/
It's probably not overly important how the 6502s got sourced for the
Apple I, but here's a different take. Debate as you see fit, I'm just
the messenger.
Jim
--
Jim Brain
brain(a)jbrain.com
www.jbrain.com
Hey all! So, I've found myself studying up on RS-232 this year for a few
reasons.
I'm mulling over doing an RS232 themed talk at June VCF. Not a super
exciting topic, but I do think that RS232 has an interesting history: In
the SAGE relationship, and as a follow up to (essentially) prior telegraph
communication.
From what I've read, "50 baud" was a kind of an initial goal to beat, since
that's what the top telegraph operators could achieve (in small burst,
probably not all day). And those operators did have to also deal with
things like start/stop "bits". Maybe it wasn't an intentional goal, but
just that it establishes why "50 baud" is generally the lowest we ever see
mentioned (or, if you go slower than that, might as well use the older
tech).
Then 75/110/130 baud to have digital-systems interoperate with classic
mechanical teletypes. Going any faster and those systems jam up or
overheat? These weren't yet called "serial ports", so I'm not sure what a
late 50s system would even call their equipment that facilitate this data
exchange (since I'm not sure what kind of crystal-clock they even had
yet).
Then, was it the SAGE program that demonstrated the idea of doing this kind
of data exchange across copper phone lines? That is, the idea of computers
collaborating not just in a room, but across long distances (miles)? And
doing so by using an audio tone presentation? (they settled on around
3100MHz, which ended up translating to 300 baud? hence, that's basically
why the first digital to digital system data exchange settled on that baud
rate, which was reliable on both 50 and 60Hz power systems, and
meaningfully faster than prior 110 baud - so a good milestone to turn it
into a product, which was the Bell Model 103?).
I couldn't find much details (like a manual) on the Bell 101 equipment
(anyone seen one or have a manual?). But I did find the Bell 103 manual -
the photo of its innards is grainy, so I don't understand how the Bell 103
did 300 baud without a UART (and one of the pinout lines I see did run
power, so not sure if that's-yet RS232 or not; I know RS232 was evolving
right at that same time circa 1962). I've about the 1970ish TR1402
initial DIP UART, with anything prior being an experiment (like a full
board concept by DEC).
I know from 1962, both RS232 and ASCII standards still took maybe another
decade to really gain traction as standards (at least, from what I've
read). Getting the world to comply with any standard always takes a lot of
effort (for a practical reason of everyone still having invested in the
older tooling that was still functional). But it's interesting how those
two standards are still in use (not in their original form, but least the
1967 revisions) - extending from Baudot.and late 1800s-tech on telegraphs.
Does anyone know of any grocery stories using RS232 in the 1960s? I think
barcode scanning was just introduced in that era. I can just imagine a
smart grocery store owner, in the backroom programming their minicomputer
for payroll and inventory management. In FORTRAN and without a CRT?
Actually, in the 60s, I think included software would be negotiated with
the provider of the computer (well, I'm not sure how that differed between
minis and mainframes).
I know early microcomputers used RS232 for keyboards (1974-1976 era). The
IBM PC keyboard is essentially another form of serial.
Well, sorry for the rambling - have other RS232 related questions, but
first wanted to focus on the historical aspects (and see if I'm somewhat on
the right track at least).
-Steve
On Fri, 14 Feb 2025 12:00:07 -0600
cctalk-request(a)classiccmp.org wrote:
> I can't believe people do use it any more without filtering. I've
> used an ad-blocking web browser for some years but I occasionally see
> the real thing when setting up a new machine. Absurd.
It really is astonishing how bad it's gotten - fully the equal of the
early '00s when sites might just spawn a dozen pop-ups and only one of
the major browsers let you block them, only now there's a pile of JS
mining crypto in the background, to boot :/ Been running with NoScript
and an ad-blocker as my standard configuration for many, many years
now, but it's always sobering to get a look at what other people see...
I am about to get a NCR EM-D2 card reader, but I can not find much
documentation on it.
Is there anyone here that has documentation on it? Preferably a maintenance
manual.
A couple of years ago (perhaps in February 2021 if one studies how
they indexed the file in their storage) there was a sale of a maintenance
manual on Ebay according to the below Worthpoint link.
https://www.worthpoint.com/worthopedia/1965-ncr-em-d2-punched-card-reader-3…
Did anyone here buy this manual? I am very interested in a scan of this
manual or possibly to purchase the manual.
/Mattis
Does anyone know anything about the whereabouts of Megan Gentry, former
RT-11 developer?
She left her last trace in 2020, when she ported ZEMU to RT-11.
We invite you to take part in a brief, anonymous survey about VCF Montreal.
Click here https://bit.ly/vcfm2026pre-en
Nous vous invitons à participer à un bref sondage anonyme sur VCF Montréal.
Cliquez ici https://bit.ly/vcfm2026pre-fr
Jeff Brace
Vintage Computer Federation Vice President
I'm repairing/restoring a later model MITS 8 inch floppy drive. I can not
seem to find schematics for it. It is
the same as Bill Degnan has here:
https://vintagecomputer.net/MITS/88-DCDD/
You can see in his photos (and mine match) that the _plus_ 24 volt DC supply
on the board uses a 7924 (note the
9. negative) voltage regulator, with a small heat sink, directly on the
circuit board. Along with a couple of 7805s,
there is a .Motorola 2n6045 screwed to the large black heat sink. All three
of the devices drop into sockets on the
circuit board to allow the heat sink to be easily installed/removed. On my
unit, the socket for the 2n6045 was burnt
to a crisp. I have replace the socket, the 2n6045, the 7924 and the
electrolytic caps. When I test the +24 volt rail
with a dummy load, it measures +41 volts.
I don't understand this circuit. I know MITS was notorious for its power
supplies. Does anyone have the schematics
for this version of the 8 inch floppy? Any suggestions?
Thanks,
Bill S.
--
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