A couple of updates on my efforts to implement the IBM 1410 in an FPGA
using the ALDs translated into VHDL, especially 1401 mode.
The 1410, with card, print and tape I/O works and passes most diagnostics.
I have also been testing IBM 1401 I/O - card, print and tape, and the
I/O is 95+% there as well, and passes the 1410 1401 CPU diagnostics.
The I/O diagnostic M012A can be coaxed into running without errors so
long as I don't load and start the card reader until the diagnostic has
issued the first 1401 opcode "1" card read instruction. The I/O
diagnostic M014B gets most of the way through under the same
conditions. The FPGA implementation current throws away SS stacker
select controls in 1401 mode, which unlike the 1410 come after the
associated card read or card punch instruction, which will necessitate
having the C# support program hold on to a card image for a period of
time in case an SS follows.
The IBM 1410 operating system 1410-PR-108 works, and I have tested
Autocoder, COBOL and FORTRAN. For FORTRAN one cannot do much because I
don't have its relocatable library or linker. I expect RPG will work as
well, but haven't run it on the FPGA.
The IBM 1410 operating system 1410-PR-155 works, including system
generation under Autcoder, FORTRAN and COBOL.
I have not yet tried any 1401 language processors, but expect to do that
over the coming weeks. I expect they will mostly run OK, based on the
fact that the tape library we had at the U. Wisconsin School of Business
had the 1401 FORTRAN II card based compiler, and tapes for 1401
Autocoder (don't remember if that was with/without Macros or IOCS) and
FORTRAN IV and maybe even COBOL.
I have created a page with information and downloads that can be used
with my FPGA implementation, and also with my 1410 simulator (no 1401
mode there) written in Borland/Embarcadero Rad Studio C++, and also with
Rich Cornwell's Simh i7010 implementation.
*https://www.computercollection.net/index.php/ibm-1410-7010-software-and-examples/
*My FPGA project information is described at
https://www.computercollection.net/index.php/ibm-1410-fpga-implementation/
, which needs multiple project progress updates now. ;)
My Simulator project information is described at
https://www.computercollection.net/index.php/ibm-1410-simulator/
The project on GitHub are:
The FPGA project: https://github.com/cube1us/IBM1410FPGA
The C# Console for the FPGA: https://github.com/cube1us/IBM1410Console
The C# program for capturing ALD information and generating VHDL:
https://github.com/cube1us/IBM1410SMS
The Embarcadero C++ based Simulator: https://github.com/cube1us/1410
JRJ
Mike -
Boundless Technologies still perform repairs (based on available parts) on terminals they manufactured for ADDS, DEC, and others. They also sell new keyboards (6-pin mini-DIN) with different layouts.
There are other repair/service centers for Serial Terminal and Keyboards, like Jetstar in Marietta, GA.
Place CUDIG in Champaign county on your Speed Dial list.
eBay reseller CUDIG61872 is located in Salorus, IL (just south of Champaign, IL).
He sells repair parts and restored serial terminals (DEC, HP, others).
He has attended VCFMW in the past (before COVID).
Reportedly he has replacement Amber CRT for the ADDS terminal refurshment (lists on eBay).
Control System Labs
1501 Kensington Ave.
Buffalo, NY 14215
greg
==
I have an ADDS Viewpoint serial terminal that has a bad keyboard.
Does anyone have a compatible key board to spare?
Also, I'm planning to have 2 different 4 user systems up and running at VCF Midwest and I only have 2 working serial terminals (VT220 & VT330+) does anyone (preferably in the Chicago area) have a terminal or two they are looking for a good home for on the super cheap? I don't want to have to use 6 laptops if I can avoid it.
Thanks,
Mike
bitwiz(a)12bitsbest.com
I have an ADDS Viewpoint serial terminal that has a bad keyboard. Does
anyone have a compatible key board to spare?
Also, I'm planning to have 2 different 4 user systems up and running at
VCF Midwest and I only have 2 working serial terminals (VT220 & VT330+)
does anyone (preferably in the Chicago area) have a terminal or two they
are looking for a good home for on the super cheap? I don't want to
have to use 6 laptops if I can avoid it.
Thanks,
Mike
bitwiz(a)12bitsbest.com
At Sat, 1 Aug 2026 20:42:23 -0400, David Gesswein <djg(a)pdp8online.com> wrote:
>The reader is a bunch of instrument amps that amplify to levels usable by
>Saleae logic 16 pro which has analog digitization mode and way too many
>times repurposed code to decode it. Doesn't look like I have put it online
>probably because the code is embarrassing but ok with giving it away if
>someone has use for it.
Here's an alternative to consider: Years ago I wrote a program to decode
waveforms digitized from cruddy old mag tapes in various formats,
including 7-track NRZI, 9-track NRZI, PE, and GCR, and 6-track Whirlwind.
https://github.com/LenShustek/readtape
We've read hundreds of tapes, mostly digitized using a Saleae analyzer.
I never wrote a DECtape decoder, but it would be doable.
At 12:35 PM 8/3/2026, Len Shustek wrote:
>It sounded like David has already done that, and has digitized the analog
>track data. That's what my "just software" program expects as input.
I should clarify: not a conversion of the analog track data into the encoded
bits, but digitizing the magnetic flux waveforms at a rate that provides
about 15-30 samples per cycle. The software then finds the peaks (or
zero-crossings), derives the clock when necessary, and decodes the bits.
https://www.vintagecomputer.net/browse_thread.cfm?id=833
New TU56 Tape Images Available for simH use. I will post updates on this
thread, but if anyone is interested in messing around with the images
using simH, feel free to download and explore/use.
Bill
In London (and I think some other UK cities) there's a free newspaper
available on public transport, called the Metro.
It has a small item each day called 'Today in History' giving events
that happened on that date. Today's includes the entry :
'1977 : Tandy released the TRS-80, one of the first personal computers
made available to the consumer market.'
Pleased to see a classic computer getting a mention.
-tony
