Yup! The fellow who made the kit also makes clones of Altair S100 boards, so he reused his recreation of their 4-slot S100 backplane in this project, too. The machine is not, however, compatible with any other S100-based computer.

Cool. So, it’s almost UNIBUS-like and its function. That’s so cool. Do you have a URL for the vendor? I’d love to take a peek at it.

@@alancabrera7116 Yes, although it's been out of stock for months. I bought it here: jmprecision.co.uk/shopping/pgm-more_information.php?id=154&=SID#MOREINFO You can also buy the designer's book, which describes building basically the same computer on breadboards. It's available on Amazon still: www.amazon.com/Computer-Time-Travel-microprocessor-transistors/dp/0995707200/

I tend to agree, but that's what the kit designer called it. 🙂

It has a small instruction set, and I just checked the manual to make sure I don't miss any: LDA (Load to Accumulator from address), ADD (Add to Accumulator from address), SUB (Subtract from Accumulator from address), OUT (Output the contents of the Accumulator to the Output Register), /HLT (Halt, and yes, the manual calls the mnemonic '/HLT' to remind the operator that it's active-low), JMP (Unconditional Jump to address), JC (Jump on carry to address), JNC (Jump on No Carry to address), JZ (Jump on Zero to address), JNZ (Jump on Not Zero to address). All addresses specified are 4-bits, and each opcode is also 4-bits. For opcodes that do not have an argument, the second 4-bits is ignored. I read Mr. Walker's book "Computer Time Travel" first, which describes how to build this on breadboards, then I bought the kit from him and assembled it over a period of months (not full time, obviously). Due to the high density of the boards, it was a LOT of soldering, and I suspect that I may still need to do some troubleshooting on the Zero flag (as you can see in the video, there may be a marginal transistor in the circuit or something). But, it was still a very interesting and satisfying build. It's definitely not something I'd recommend to anyone as their first electronics kit build, though! By the way, Mr. Walker encourages readers of his book to make their own designs, using his as inspiration, and to expand upon his design to make a more complex processor. For instance, there is a small provision on one board to configure the machine to bank-switch different parts of the EPROM, to allow for larger programs, but it needs some extra circuitry to make it work. I may yet do this, but I'm taking it slowly, as I'm not an electrical engineer. 🙂 I did see a short video from someone else on KZbin, who also read his book and then went on to build a scaled-down, 4-bit transistor computer on breadboards.

@@derekchristenson5711 Thank you for the detailed answer! I’m really intrigued by the idea of creating instruction set extensions. Your experience with Mr. Walker’s kit sounds inspiring-building a processor is quite an achievement, even with all the soldering! Good luck with the troubleshooting on the Zero flag!

@@TobosTechChannel Thank you!

Thanks! Funny story about it: I got that as a "birthday gift" one year... but, it wasn't my birthday, not even near it, and I didn't know the guy who signed the card. Having no way to contact him, I had no way to thank him (nor to suggest that he had presumably made a mistake), but it gave me a nice way to keep small tools and writing implements handy!

@@derekchristenson5711 you have no idea how lucky you are

Thank you!

LOL, I couldn't say! But, yes, it was a fun project, although it was also long, complicated, and at times quite difficult. 🙂

Thanks!