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What good are S-100 systems for?

ardent-blue

ardent-blue

Experienced Member
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Jan 2, 2015
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Through a chain of events, I was shipped an S-100 a year or so ago, and the buyer was going to come over from the UK, visit some folks, swing by and pick it up, and fly back.

Never happened. WBST slipped out the back door, and he's living large somewhere.

So I have a S-100 in a cardboard box, and it's still unopened [NOT the original box!]. PS/2s, done them, been there, got the T-shirt.

Boat anchor? Skynet? Chat GTP? Talk to me, 'cuz I have little ideal...
 
What cards are installed in the S100 chassis? S100 covers a wide range of possibilities. Most likely, the typical S100 system would be for a multi-user CP/M operation. I don't know how long having two users of Wordstar on the same computer can provide amusement.
 
I have a big pile of S-100 stuff, and I should take it all to VCFW in Aug and get rid of it all.
It is a nostalgic challenge that I lived through in the 70s, and after trying to get an IMSAI
running reliably with 40 year old edge connectors a few years ago, I'm just going "meh..."

There are kids out there who have never had that pain. It's time to hand it all off to them.

The only exception would be the Morrow Tricep to just have the challenge of running a
68000 S-100 Unisoft Unix running, which I couldn't afford at the time.
 
I have a Northstar Horizon I got for free, and, well... I'll be honest, after an initial flurry of activity cleaning it up and regenerating the power supply capacitors I've had issues ranking continuation of the restoration project very high on the project list. While on one level I appreciate the sheer brute force engineering that went into these machines they can also come across as needlessly overcomplicated, inefficient, and fiddly compared to architectures designed just a couple years later. And, gotta be honest, unless you have some "interesting" cards to play with there's really nothing from a user-facing standpoint that makes poking at a Northstar Horizon over a serial terminal significantly different from hooking that same terminal up to a modern Z80 SBC the size of a postcard.
 
I have had fun with S-100 systems because they lend themselves very well to making home made boards & projects for them. One board I designed was for a light pen and another carrying ROMs. On the other hand 8 bit custom ISA cards for IBM computers are easy & fun too.
 
Hugo Holden said:
I have had fun with S-100 systems because they lend themselves very well to making home made boards & projects for them.
Click to expand...

One killer is the price of hard gold edge connectors on new PCBs for any of the old edge connector bus.
If I need to make a something with a bus connection, I just use a pin and socket like 96 pin DINs. The
state of the art has advanced a LOT in low insertion force connectors over the last 50 years. Trying to pull
a card out of an old high insertion force PCB edge connector socket is no fun.
 
Some latter day pcb's for vintage edge connector use , the designers forgot to put a shallow taper on the board edge to ease them into the connector sockets. So high force is required then they enter the connector very abruptly, which is not good. With the right taper on the board edge, they go in and out pretty easily.
 
Don't forget, back in the day, when S-100 machines were the big kids on the block, there were reasons why the 5150 & 5160 changed everything in a very, very short time.

Tinker very much with the machine your friend left you and you'll no doubt find out what some of those reasons were.
 
Saying you have an S-100 system is like saying you have a car in your drive.

There are multitudes of S-100 systems I am afraid, so you need to open the present and show us what you have!

Dave
 
What can an S-100 computer do? Pretty much what other computers from that era do. S-100 is the bus so it also greatly depends on what the actual S-100 cards in your computer are.
 
Like that old saying that "beauty is in the eyes of the beholder", what you find attractive in the S-100 bus, vs the IBM 51xx bus, might be in the eyes of the beholder, or it might be 8080 & Z80's vs 8088. But still with vintage gear, the magic is in your own mind, is it not, Grasshopper?
 
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VERAULT said:
How do you mean?
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A thousand apologies for the confusion.

The line should have been directed @Eudimorphodon: Does anything on that site change your project priorities?

I can only explain the mistake by promising to try in the future not to select member names when I'm exhausted and about to turn in for the night.

But the point was that, if you need interesting cards to justify a project, a lot of SBC and more modern processor boards have been designed and built to plug into S-100 systems. So one could have, for example, an S-100 based IBM PC compatible 486 that also has multiple co-processors including a 68030 and even an ARM (via raspberry pi).

A rather flexible computer can be assembled using an S-100 with the right boards.
 
S-100 is an electrically poor choice for a bus. That was known as far back as the original MITS design
resulting all of the kludges and work-arounds done to it along the way.
ISA is an electrical marvel in comparison, and that is damn faint praise.

Putting an 80486 on S-100 is the definition of putting lipstick on a pig.
 
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acgs said:
The line should have been directed @Eudimorphodon: Does anything on that site change your project priorities?
Click to expand...

Well... see, there's actually some irony there, maybe. When I got the NorthStar I got very excited about the possibilities because, yes, S-100 computers were the original personal computer Erector Sets and there were in theory a million interesting things to do with one, but between actually taking apart the machine to work on it and the extensive research I did on the standard (trust me, I'm very familiar with s100computers.com, reference manuals there and deramp.com all the time) my thoughts on things... evolved. The short version goes something like this:

Yay, I finally had a real S100 machine to play with. But... ugh, besides this thing having been living under a barn for thirty years and needing a lot of work it's just a basic "48K CP/M via serial terminal" configuration; there's no video card, and, ugh, this NorthStar disk controller uses hard sectoring and the disks (and the drives) that came with it are pretty trashed, so I'm probably going to have to build or buy something exotic to even get the original CP/M going on it. And... I hate to say it, CP/M just isn't my cup of tea. Had an Osborne for a while, still have the tee shirt, would rather have a TRS-80 unless there's something more engaging than Wordstar to do with it.

So... maybe I should use this as an opportunity to build this chassis into something more interesting instead of restoring it as is? Hey, you know what's cool and interesting? Ancient video cards like the ones from Processor Tech and Polymorphic systems! After turning white as a sheet seeing what original cards were selling for I decided this was clearly the time to start learning enough about how video systems worked to see if I could build my own S100 video card that could emulate for some of those truly ancient originals. This project is still ongoing, but... I have to be honest:

Al Kossow said:
S-100 is an electrically poor choice for a bus. That was known as far back as the original MITS design
resulting all of the kludges and work-arounds done to it along the way.
Click to expand...

that project has kind of morphed into just building a whole computer from scratch because S100 started to come across as a real *hassle*. The bus is really oddly laid out (that whole deal with the bipolar data bus alone... which then isn't bipolar if you're making an IEEE-696 compliant card), the cards are physically huge (you're definitely not going to get the discount rate from PCBway), you have to do your own voltage regulation on every card... it suddenly starts looking like a lot of extra work to use the beat up backplane board in that Northstar for experimentation/prototyping than it'd be to just bang together a simplistic ISA-like bus using standard 0.1" spacing pin headers. (IE, something like the RC2014.) I mean, I do have a Z80 and a RAM card in the Northstar, sure, but they're dreadfully complicated, feel kind of fragile (I diagnosed a nasty voltage regulator issue with the RAM card and ended up making an Arduino-powered 4116 tester to see if all the RAM chips got fried... I don't *think* so, but I haven't gotten around to getting the machine into a bootable state yet), and I can pretty much replicate them with a Z80, a single SRAM, and a couple GALs.

Anyway, not to say I'm not going to try to finish restoring that Northstar, it's a piece of history, but I feel like I talked myself out of using it as a hacking platform for now. If I get the homebrew video dingus fully baked I probably will try to spin an S100 adapter for it and see if I can achieve my original goal of running some early software targeting things like the VDM-1 and Poly-88 on a real S100 chassis but... yeah. As much as it pains me to say it I kind of felt like having an S100 around turned into one of those "Never meet your heroes" moments.
 
... now to be clear, I guess, if an Altair/IMSAI/SOL-20/Poly-88 that *did* have some neat original cards in it fell out of the sky into my backyard I'd probably switch gears again and have at it. Gotta admit that some of it really is the poor Northstar just not being cool enough.(*)

(* Okay, to be fair, that hard sector disk controller is a kind of amazing piece of work from a technical standpoint, and since the FlashFloppy firmware for Goteks apparently has experimental hard sector support now I do hope to play with it eventually.)
 
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