The PSI Comp 80 was a

home computer Home computers were a class of microcomputers that entered the market in 1977 and became common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a s ...

sold by Powertran starting in 1979. It was sold in the form of a kit of parts for a cased single-board home computer system. The system was based on a

Z80 The Zilog Z80 is an 8-bit microprocessor designed by Zilog that played an important role in the evolution of early personal computing. Launched in 1976, it was designed to be software-compatible with the Intel 8080, offering a compelling altern ...

microprocessor A microprocessor is a computer processor (computing), processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, a ...

addressing a mixture of 8 KB of system

RAM Ram, ram, or RAM most commonly refers to: * A male sheep * Random-access memory, computer memory * Ram Trucks, US, since 2009 ** List of vehicles named Dodge Ram, trucks and vans ** Ram Pickup, produced by Ram Trucks Ram, ram, or RAM may also ref ...

and

EPROM An EPROM (rarely EROM), or erasable programmable read-only memory, is a type of programmable read-only memory (PROM) integrated circuit, chip that retains its data when its power supply is switched off. Computer memory that can retrieve stored d ...

, plus 2 KB of

video RAM Video random-access memory (VRAM) is dedicated computer memory used to store the pixels and other graphics data as a framebuffer to be rendered on a computer monitor. It often uses a different technology than other computer memory, in order to b ...

. It used a

National Semiconductor National Semiconductor Corporation was an United States of America, American Semiconductor manufacturing, semiconductor manufacturer, which specialized in analogue electronics, analog devices and subsystems, formerly headquartered in Santa Clara, ...

MM57109N as a mathematical co-processor to speed up calculations.

History and specifications

In 1979, the British magazine ''

Wireless World ''Electronics World'' (''Wireless World'', founded in 1913, and in October 1983 renamed ''Electronics & Wireless World'') is a technical magazine published by Datateam Business Media Ltd that covers electronics and RF engineering and is aimed at ...

'' published the technical details for a "Scientific Computer". Shortly afterward the British firm Powertran used this design for their implementation, which they called the PSI Comp 80. Ahead of its time, it incorporated a number crunching coprocessor and a novel language embedded in EPROM called Basic Using Reverse Polish - BURP. The monochrome

Video Display Controller A video display controller (VDC), also called a display engine or display interface, is an integrated circuit which is the main component in a video-signal generator, a device responsible for the production of a TV video signal in a computing ...

could simultaneously display combinations of 32 lines of 64 characters, and 128 x 64 resolution graphics by either displaying a normal character or a " pseudo graphics" character, with

pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, p ...

blocks in a 2x2 matrix. A technique similar to the one used in the

TRS-80 The TRS-80 Micro Computer System (TRS-80, later renamed the Model I to distinguish it from successors) is a desktop microcomputer developed by American company Tandy Corporation and sold through their Radio Shack stores. Launched in 1977, it is ...

- It could later be expanded to a higher resolution, although never to colour. Add-ons were developed for the system, including memory expansions, floppy and hard disk interfaces, various software packages and a disk

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

, SCIDOS, which was

CP/M CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/Intel 8085, 85-based microcomputers by Gary Kildall of Digital Research, Dig ...

-compatible but also included features - structured (pathed) disk folders, etc. - now very familiar to modern-day PC users. During the mid-1980s, the designer of this system, John Adams M.SC., published a new version of the Scientific Computer - the SC84 (Scientific Computer of 1984). It was based upon a

backplane A backplane or backplane system is a group of electrical connectors in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors, forming a computer bus. It is used to connect s ...

and plug-in cards and modules and featuring a

Hitachi () is a Japanese Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1910 and headquartered in Chiyoda, Tokyo. The company is active in various industries, including digital systems, power and renewable ener ...

HD64180 The HD64180 is a Z80-based embedded microprocessor developed by Hitachi with an integrated memory management unit (MMU) and on-chip peripherals. It appeared in 1985. The Hitachi HD64180 "Super Z80" was later licensed to Zilog and sold by them ...

processor, up to 512 kbytes of

and a high-resolution colour graphics system.

References

PSI 2020

External links

a picture of the advertisement for the PSI Comp 80 in Wireless World

Links to Wireless World articles

SC84 article
Home computers Computer-related introductions in 1979 {{comp-sci-stub