ZX Microdrive

The ZX Microdrive is a magnetic tape data storage system launched in July 1983 by Sinclair Research for its ZX Spectrum home computer. It was proposed as a cheaper alternative to the floppy disk, but it suffered from poor reliability and slower speed. The Microdrive technology was later also used in the Sinclair QL and ICL One Per Desk personal computers. The minimum storage capacity of a Microdrive tape cartridge was 85 KB.

It is claimed the Microdrive was originally proposed by Andrew Grillet at an interview with Sinclair Research for what was to become the ZX81. Grillet proposed "a version of the Learjet Stereo 8 system, modified to allow two 64k core images per track for roll-out roll-in swapping using the KUTS protocol". The ZX81 had only 1 kB of RAM. Grillet was offered better pay by Xerox Corporation, and never worked on the ZX81 or the Spectrum. The primary engineer involved in the development of the Microdrive was Ben Cheese.

Typically of Sinclair Research, the ZX Microdrive was comparatively cheap (£49.95 at launch) and technologically innovative but also rather limited. Connecting a ZX Microdrive to a ZX Spectrum required the ZX Interface 1 unit, costing £49.95, although this could be bought packaged with a Microdrive for £79.95. Later, in March 1985, the ZX Spectrum Expansion System was launched for £99.95. This consisted of Interface 1, a Microdrive, a blank cartridge and several cartridges containing Tasword Two word processor plus Masterfile filing system, Quicksilva's Games Designer and Ant Attack game, and an introductory cartridge. A total of eight ZX Microdrive units could be connected to the Interface 1 by daisy chaining one drive to the next via an electrical connector block.

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