Processor Technology

Bob Marsh founded Processor Technology Corporation (a microcomputer company) in April 1975. Bob Marsh, Lee Felsenstein and Gordon French started designing the Sol-20 Terminal Computer in June 1975. The SOL-20 utilized the Intel 8080 8-bit microprocessor chip, running at 2 MHz. The SOL-20 consisted of a main motherboard (PCB) mounted at the bottom of the case, and a 5 slot S-100 bus card cage. The main PCB consisted of the CPU, memory, video display, I/O circuits. Inside the case included power supply, fan, and keyboard. The sides of case are solid oiled walnut wood, and blue painted steel. An external composite monitor screen was also needed. Processor Technology manufactured approximately 10,000 of their Sol-20 personal computers between 1977 and 1979. All Processor Technology products where available either assembled and tested, or as electronic kits. Processor Technology also sold software on Cassette tape. One side was CUTER format, and the other side was Kansas City standard format.

Making Standards

Processor Technology also designed several S-100 bus boards. The boards were meant to be compatible with the circuits of SOL-20. Most notable was the VDM-1. The Video Display Module 1 was the original video display interface for S-100 bus systems. The VDM-1 was the most popular for owners of S-100 bus systems, such as the IMSAI 8080. The VDM-1 board created a brief industry standard. The board generates sixteen 64-character lines in a large, easy-to-read, upper and lower case typeface on any standard composite video monitor or a modified TV set. By utilizing a 1,024 byte (1K) segment of system memory, VDM-1 provides extremely fast operation. For example, any character on the screen can be accessed by the processor in microseconds. Once the processor provides the display status parameters, the VDM-1 can scroll its display upward or downward at a top speed of about 1000 lines per minute. The VDM-1 is versatile with fully programmable cursor positioning. It will display black-on-white or white-on-black, perfect for many of the first ever video games. The Processor Technology VDM-1 Video Board was a great improvement over using a teletype machine or a serial attached terminals back in the glory days. It was the first Memory-mapped I/O video boards that plugged directly into the S-100 bus system.

-100 bus boards designed by Processor Technology

*VDM-1 - Video Display Module Board

*3P+S - Input/Output Module 3 Parallel plus 1 Serial Board

*4KRA - 4K Static Memory Board

*8KRA - 8K Static Memory Board

*16KRA - 16K DRAM memory board

*32KRA-1 - 32K DRAM memory board

*CUTS - Tape I/O Interface Board, CUTER format and Kansas City standard format

*2KRO - EPROM memory board

oftware by Processor Technology

*SOLOS

*CUTER

*SOLOS

*ASSM 8080 assembler

*BASIC/5 - 5K BASIC programming language

*Extended Cassette Basic

*ALS-8

*EDIT 8080 Editor

*8080 Chess

*TREK-80 - Star Trek game

*GamePack 1

*GamePack 2

External links

* [http://www.sol20.org/ Archive of Sol-20 information]
* [http://www.oldcomputermuseum.com/ Collection of old analog and digital computers at www.oldcomputermuseum.com]
* [http://old-computers.com/MUSEUM/computer.asp?c=344 the SOL-20 at old-computers.com]
* [http://www.pc-history.org/sol.htm Processor Technology SOL - PC History by Stan Veit]