PSI Comp 80 (computer)
Encyclopedia
In 1979, the British magazine Wireless World
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. 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 Microprocessor addressing a mixture of 8 KB
of system RAM
and EPROM
, plus 2 KB of Video RAM.
It used a National Semiconductor
MM57109N as a mathematical co-processor to speed up calculations.
The monochrome Video Display Controller
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 blocks in a 2x2 matrix. A technique similar to the one used in the TRS-80
- It could later be expanded to a higher resolution, although never to colour.
Ahead of its time, it incorporated a number crunching coprocessor and a novel language embedded in EPROM called Basic Using Reverse Polish - BURP.
Add-ons were developed for the system, including memory expansions, floppy and hard disk interfaces, various software packages and a disk operating system, SCIDOS, which was CP/M
-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, published a new version of the Scientific Computer - the SC84 (Scientific Computer of 1984). It was based upon a backplane and plug-in cards and modules and featuring a Hitachi
HD64180
processor, up to 512 kbytes of RAM and a high resolution colour graphics system.
Wireless World
Wireless World was the pre-eminent British magazine for radio and electronics enthusiasts. It was one of the very few "informal" journals which were tolerated as a professional expense.- History :...
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. It was sold in the form of a kit
Electronic kits
An electronic kit is a package of electrical components used to build an electronic device. Generally, kits are composed of electronic components, a circuit diagram , assembly instructions and often a printed circuit board or another type of prototyping board.There are 2 distinct types of kit,...
of parts for a cased single-board home computer system.
The system was based on a Z80 Microprocessor addressing a mixture of 8 KB
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
of system RAM
Ram
-Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...
and EPROM
EPROM
An EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...
, plus 2 KB of Video RAM.
It used a National Semiconductor
National Semiconductor
National Semiconductor was an American semiconductor manufacturer, that specialized in analog devices and subsystems,formerly headquartered in Santa Clara, California, USA. The products of National Semiconductor included power management circuits, display drivers, audio and operational amplifiers,...
MM57109N as a mathematical co-processor to speed up calculations.
The monochrome Video Display Controller
Video Display Controller
A Video Display Controller or VDC 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 or game system...
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 blocks in a 2x2 matrix. A technique similar to the one used in the TRS-80
TRS-80
TRS-80 was Tandy Corporation's desktop microcomputer model line, sold through Tandy's Radio Shack stores in the late 1970s and early 1980s. The first units, ordered unseen, were delivered in November 1977, and rolled out to the stores the third week of December. The line won popularity with...
- It could later be expanded to a higher resolution, although never to colour.
Ahead of its time, it incorporated a number crunching coprocessor and a novel language embedded in EPROM called Basic Using Reverse Polish - BURP.
Add-ons were developed for the system, including memory expansions, floppy and hard disk interfaces, various software packages and a disk operating system, SCIDOS, which was CP/M
CP/M
CP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
-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, published a new version of the Scientific Computer - the SC84 (Scientific Computer of 1984). It was based upon a backplane and plug-in cards and modules and featuring a Hitachi
Hitachi
Hitachi is a multinational corporation specializing in high-technology.Hitachi may also refer to:*Hitachi, Ibaraki, Japan*Hitachi province, former province of Japan*Prince Hitachi and Princess Hitachi, members of the Japanese imperial family...
HD64180
HD64180
The HD64180 is a Z80-based embedded microprocessor developed by Hitachi with an integrated memory management unit . The Hitachi HD64180 "Super Z80" was later licensed to Zilog and sold by them as the Z64180 and with some enhancements as the Zilog Z180. It has the following features:* Memory...
processor, up to 512 kbytes of RAM and a high resolution colour graphics system.