Tandy TRS-80 Model I

1977 – Mid 1980’s


The TRS-80 Micro Computer System (TRS-80, later renamed the Model I to distinguish it from successors) is a desktop microcomputer launched in 1977 and sold by Tandy Corporation through their Radio Shack stores. The name is an abbreviation of Tandy/Radio Shack, Z-80 microprocessor. It was one of the earliest mass-produced and mass-marketed retail personal computers.

The TRS-80 featured a full-stroke QWERTY keyboard, the new Zilog Z80 processor (rather than the more common Intel 8080), 4 KB DRAM standard memory (when many 8-bit computers shipped with only 1 KB RAM), small size and desk footprint, floating-point BASIC programming language, standard 64-character/line video monitor, and a starting price of US $600 (equivalent to US $2400 in 2017).

An extensive line of upgrades and add-on hardware peripherals for the TRS-80 was developed and marketed by Tandy/Radio Shack. The basic system could be expanded with up to 48 KB of RAM (in 16 KB increments), and up to four floppy disk drives and/or hard disk drives. Tandy/Radio Shack provided full-service support including upgrade, repair, and training services in their thousands of stores worldwide.

By 1979, the TRS-80 had the largest selection of software in the microcomputer market. Until 1982, the TRS-80 was the best-selling PC line, outselling the Apple II series by a factor of 5 according to one analysis.