Most recent revision dated April 20 2010, our THIRTEENTH year of providing S-100 information on the Web.
I'm Herb Johnson, in New Jersey USA. I provide some support services for old S-100 and IEEE-696 (IMSAI, Altair, Compupro, etc.) computers. For more information on S-100, check my S-100 Stuff Home page. For a technical description of the S-100 bus and IEEE-696 bus, and a few more photos for use, check my S-100 bus technical page.
This is a photo of a MITS Inc Altair 8800 CPU board. This was the first "S-100" product, but at that time it was simply the first Intel 8080 CPU board for MITS's Altair 8800 computer, first offered in January 1975. Note the gold edge connector of 50 pins; there are 50 more pins on the reverse edge as well. Almost immediately, several Altair 8800 systems were bought by designers, who produced "Altair bus compatible" cards and later systems. In a few years these cards and systems were known as "S-100 compatible", after the 100-pin bus the cards all plugged into. By the mid-1980's over 140 companies produced S-100 products. Read my S-100 Web pages for more information.
This is a photo of a Compupro brand S-100 motherboard. The original Altair bus was simply 100-pin board connectors with pins wired in common, and connectors for power and reset. Within a few years of production of S-100 boards and systems, there needed to be an expansion of the S-100 bus to support faster cards and more memory, and features like "multi master" or switchable CPU boards. Several producers created and supported cards to what became the IEEE-696 standard, supported by the IEEE, a national electrical engineering organization. This board also includes bus termination features which were not part of the original Altair bus. Read my S-100 Web pages for more information.
This is a photo of a Compupro brand 80286 CPU board.After the introduction of the S-100 bus and its Intel 8080 based CPU by MITS in 1975, microprocessor technology
advanced, and S-100 cards were created to support that technology. New processors, more memory, more mass storage were all supported with S-100 or IEEE-696 cards. This 1985 board by Compupro has an Intel 80286 processor and a socket for the 80287 floating point processor. Other processor boards of the era included the Motorola 68000, the National Semi 16032, and many 8-bit processors such as the 6800, 6502, and so on. But the Intel processor line was the most popular for S-100 and IEEE-696 systems. Note: this card was produced years after the IBM PC of 1981; S-100 systems were developed, sold and in use for many years after the so-called "IBM PC revolution". Read my S-100 Web pages for more information.
- Herb Johnson
Copyright © 2010 Herb Johnson