Incorporating revolutionary media and circuit design features, the Sinclair ZX Microdrive enables storage of programs, blocks of code, screens, arrays and data files on removable cartridges each with at least 85K bytes capacity.
Each cartridge may contain up to 50 files which can be individually identified, sorted automatically, and displayed in alphabetical order or deleted — with typical access times of 3.5 seconds. The Microdrive controller, contained within ZX Interface 1, expands Sinclair BASIC to include file-handling and communications facilities, and introduces BASIC as an operating system as well as a programming language. Up to eight Microdrives may be used by a single Spectrum and Interface 1, giving a total of 680K bytes capacity.
Also contained within the ZX Interface 1 are an RS232 interface and local network, the complete unit attaching to the underside of the Spectrum and duplicating the latter's peripheral port.
The RS232 industry standard serial interface enables the Spectrum to drive full-size printers and to communicate with other computers having the same interface; it also permits transmission of data over telephone lines. The local area network, on the other hand, acts as a high speed communications link between up to 64 Spectrums (or should that be Spectra?) transmitting at 100 kilobaud.