The new Altair-Duino Pro in a full size Altair cabinet ... idea?

[Walt Perko]

Hi, 

I was just thinking that if the cabinet is full size, maybe the I/O expansion scheme could be tied to a real S-100 buss backplane so we could install real S-100 buss cards into the computer.  

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[Tom Lake]

There are some signals that the expansion bus doesn't reproduce so you'd be limited in your selection of boards. Why not build an 8800c instead? Then you'd get full Altair compatibility.

[Walt Perko]

Hi, 

Okay, that seems logical.  

I just keep thinking that if the Altair-Duino Pro could run a real S-100 buss, then it might be something to entice more hobbyists to get started.  Having both the 8080 and Z80 in the Altair Z80 Pack and most functions of a real Altair 8800 computer, the front panel and Arduino DUE is a much simpler starter system.  

I haven't seen much about builds with the reproduction full size cabinets.  Has anybody done anything with a larger than 4-slot or 6-slot I/O expansion backplane?  

There should be a list (a .PDF or maybe a spreadsheet) of each board, it's normal address range, function and how to set it up with other external devices.  

A page or two showing from start to finish all the connections, addressing, external devices and how they operate would be a very useful tool.  For boards like the ACR or Cassette I/O maybe even oscilloscope test points and photos showing what the signal should look like in important places.  

Of course the same for the DAZZLER, the VersaTerm and the VDM-1 in a Geoff Graham terminal ... and maybe another terminal if there are any that would be compatible.  

I do like the bigger cabinet, but were I to buy another one (I already have an Altair 8800c computer) ... I would still want the full size S-100 buss.  

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[Tom Lake]

I have an 18-slot motherboard in mine. I just had to take a Dremel to the two side gussets and cut notches in them.
They still hold the front panel in place nicely, though.

[Walt Perko]

Hi, 

No photos?  Are there that many I/O Expansion boards now?  

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[Tom Lake]

There's one limitation of the Duino expansion system. Add-on cards can't generate interrupts so serial cards can't be used with Multi-User BASIC.

That's a show-stopper for me.

On Tuesday, June 17, 2025 at 1:10:04 PM UTC-4 John Galt wrote:

There are 10 cards. but then if you double up some of the cards like the disk controller or if you add more serial/parallel ports you could start to fill up 18 slots.

it depends what cards you feel are the most useful for your plans.

[David Brunell]

I've always thought the S-100 bus was a bit of overkill. The IBM PC did just fine with a 62-pin bus, and that's with a 20-bit address space. If I were to design my own bus for an 8-bit system, it would likely be based on the 44-pin form factor.

[dmt atgm]

Having been introduced to the s100 bus in its infancy, it was the beginning of standardization. Different manufacturers could design different boards that would work with other boards from other manufacturers. This gave rise to different concept such as multi user system in a distributed cpu environment or hardware addressable via api OS.

Wonderful time and era to be an IT tech in those days.

noroads...@gmail.com

Micro-controllers, electric trains, RC models

On Jun 20, 2025, at 19:57, David Brunell <quant...@gmail.com> wrote:

I've always thought the S-100 bus was a bit of overkill. The IBM PC did just fine with a 62-pin bus, and that's with a 20-bit address space. If I were to design my own bus for an 8-bit system, it would likely be based on the 44-pin form factor.

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[Tom Lake]

That was especially true after the IEEE S-100 standard came out. Before that, getting some boards to work with some systems was a crapshoot.