Feeds

Love on the buses: The S-100 and me

An illustrated affair

The Essential Guide to IT Transformation

Let's put this puppy together

The case that I picked out of Byte from the now-defunct XOR Corporation had a beefy power supply to feed its four eight-inch drive bays and S-100 slots. "Bays," however, is overstated - "holes" is more to the point, since you had to supply your own mounting brackets.

This Old Box - XOR S-100 power supply

Power is supplied by a huge transformer that feeds equally huge capacitors

The S-100 bus in the XOR enclosure's "card cage" had a dozen slots - a normal amount at the time. I'd seen enclosures with more, and I'd seen enclosures with fewer. Even though I knew I didn't plan to use all the slots, I wanted to leave space for ventilation.

This Old Box - S-100 bus card cage

This S-100 bus card cage has room for a dozen cards

Installing cards was a snap - literally. You simply pushed them down into the slots at the bottom of the cage. First, though, you had to dig through opaque manuals and discover exactly how to set the cards' myriad jumpers and DIP switches - and if you don't know what a DIP switch is, consider yourself lucky. And young.

Interestingly, I discovered that the order of the cards affected how well the system ran - latencies and timing issues, I assume. Much of computer assembly in those days was done by the seat of one's pants.

This Old Box - S-100 card slots

At the base of the S-100 card cage are 100-pin slots

Although there were a number of reputable S-100 card companies in those day - meaning folks who actualy believed in such niceties as warranties - I was partial to Bill Godbout's CompuPro line, having used his machines at work. I could just as easily have gone for cards by Cromemco, California Computer Systems, or some other, but I stuck with what I knew.

This Old Box - S-100 CompuPro CPU 8085/88 card

The CompuPro CPU 8085/88 card - pick a processor

The CompuPro CPU 8085/88 (PDF) was a dual-processor card that contained a 16-bit AMD 8088 and an eight-bit Intel 8085. You could switch back and forth between the two in software, thus avoiding popping the case open and setting a jumper every time you wanted to switch.

This Old Box - Intel 8088 and 8085

AMD 8088 (left) and Intel 8085 - notice that each chip has just 40 pins

The 8088 was essentially an 8086 that could deal with the eight-bit S-100 bus. Its combination of 16-bit insides with an eight-bit approach to the outside world made it a good chip for the S-100 bus, offering a convenient way to use an eight-bit file system like CP/M 2.2 and still develop 16-bit code.

Build a business case: developing custom apps

Next page: Card games

More from The Register

next story
4K video on terrestrial TV? Not if the WRC shares frequencies to mobiles
Have your say with Ofcom now, before Freeview becomes Feeview
iPad? More like iFAD: We reveal why Apple fell into IBM's arms
But never fear fanbois, you're still lapping up iPhones, Macs
Sonos AXES support for Apple's iOS4 and 5
Want to use your iThing? You can't - it's too old
You didn't get the MeMO? Asus Pad 7 Android tab is ... not bad
Really, er, stands out among cheapie 7-inchers
Apple winks at parents: C'mon, get your kid a tweaked Macbook Pro
Cheapest models given new processors, more RAM
Leaked Windows Phone 8.1 Update specs tease details of Nokia's next mobes
New screen sizes, dual SIMs, voice over LTE, and more
YES, iPhones ARE getting slower with each new release of iOS
Old hardware doesn't get any faster with new software
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Maximize storage efficiency across the enterprise
The HP StoreOnce backup solution offers highly flexible, centrally managed, and highly efficient data protection for any enterprise.