Processor Technology

Processor Technology
Name	Processor Technology
Fate	Defunct
Foundation	0 1975
Defunct	0 1979
Location	Emeryville, California
Key people	Bob Marsh, Gary Ingram
Industry	Computer hardware
Products	SOL-20, Processor Technology 3A

Processor Technology. It was a pioneering American microcomputer company founded in 1975 by engineers Bob Marsh and Gary Ingram. Operating from Emeryville, California, the company became famous for its SOL-20 terminal computer and its influential hardware for the S-100 bus. Processor Technology was a central player in the Homebrew Computer Club ecosystem and a significant contributor to the early microcomputer revolution before ceasing operations in 1979.

History of processor development

The company's origins are deeply intertwined with the Homebrew Computer Club, where founders Bob Marsh and Gary Ingram were active participants. Their first major product was a dynamic RAM board for the Altair 8800, which addressed the memory limitations of early kits. This success led to the development of the SOL-20, a fully assembled computer showcased at the inaugural Atlantic City Computer Festival in 1976. The machine, which combined a Zilog Z80 processor with a Video Display Module, was lauded in publications like Byte (magazine) and Popular Electronics. Despite this acclaim and the later introduction of the Processor Technology 3A dot matrix printer, the company faced intense competition from rivals like Apple Computer, Commodore International, and Tandy Corporation. Financial difficulties mounted, leading to its closure in 1979, a period marked by the broader 1979 energy crisis.

Basic architecture and components

The flagship SOL-20 was built around the S-100 bus, an open architecture popularized by the Altair 8800. Its central processing unit was the Zilog Z80, an 8-bit microprocessor that was an enhancement of the Intel 8080. A key innovation was its integrated Video Display Module, which provided a direct video output for a monitor or television, a feature not standard on many contemporaries. The system typically utilized dynamic RAM boards designed by the company and could run the CP/M operating system from Digital Research. Expansion was facilitated through the S-100 bus, allowing for the addition of floppy disk controllers from manufacturers like North Star Computers and PerSci, Inc..

Types of processors

While Processor Technology did not fabricate microprocessors, its systems were defined by their CPU selections. The SOL-20 exclusively used the Zilog Z80, which offered superior performance and instruction set compatibility compared to the earlier Intel 8080. The company's memory and interface boards, however, were designed to be broadly compatible with any S-100 bus computer using a variety of processors, including the Intel 8080, the MOS Technology 6502, and later, the Intel 8086. This focus on the S-100 bus ecosystem meant its hardware interacted with systems from companies like IMSAI, Cromemco, and Vector Graphic.

Manufacturing process and technology nodes

As an early original equipment manufacturer, Processor Technology's manufacturing involved the assembly of discrete electronic components onto printed circuit boards. The company did not engage in semiconductor fabrication at the integrated circuit level; it sourced chips like the Zilog Z80 from external semiconductor fabrication plant vendors. Its operations were characteristic of the era's California Silicon Valley startup culture, involving small-scale assembly, often relying on technical documentation published in magazines like Interface Age. The physical construction of the SOL-20, with its distinctive welded metal case, was a step towards more polished consumer products compared to bare kit computers.

Performance metrics and benchmarks

Performance for systems like the SOL-20 was gauged by contemporary standards of the mid-1970s. Key metrics included processor clock speed, which for the Zilog Z80 was typically 2 MHz, and memory capacity, which could be expanded to 64 KB using the company's dynamic RAM boards. Practical performance was demonstrated by its ability to run the CP/M operating system and business software like WordStar and dBASE. Reviews in Byte (magazine) and Kilobaud Microcomputing often highlighted its superior video display output and build quality compared to competitors like the IMSAI 8080 or the Apple II.

Current trends and future directions

Although Processor Technology ceased operations decades ago, its legacy informs several modern trends. Its advocacy for open architecture, exemplified by the S-100 bus, prefigured later movements in open-source hardware. The company's story is a canonical case study in the rapid evolution and fierce competition of the personal computer industry, taught alongside the histories of IBM, Microsoft, and Xerox. The SOL-20 remains a prized item among collectors and institutions like the Computer History Museum, which preserve it as a key artifact of the microcomputer revolution. The ethos of community-driven innovation seen at the Homebrew Computer Club continues to resonate in today's maker culture and hackerspace communities.

Category:Defunct computer companies of the United States Category:Homebrew Computer Club Category:Microcomputer companies