Sinclair never did the
obvious, and this was perhaps most evident in his
quirky Microdrive mass storage device. It was
intended to be a budget alternative to
then-expensive floppy disks, and in fact was
something of an engineering miracle. It was
moderately successful and second-hand Microdrives
are today quite common, though working
ones are rather harder to find.
first Microdrives were produced for the Spectrum and cost £50 (but you needed a £50
Interface 1 as well). The QL also used Microdrives,
though QL and Spectrum Microdrive cartridges used
different formats and so could not exchange data.
Inside each cartridge (technically known as a
"stringy floppy") was 6 meters of 1.9mm
magnetic tape, which ran at 76cms per second,
enabling the storage of 85K of data.
Unfortunately, the cartridges were expensive,
relatively scarce, prone to tangling and did not
have a long service life. Technology soon
overtook the Microdrive;
the price of conventional disk drives fell,
although Amstrad had bought the rights, the
Microdrive was abandoned - instead, Amstrad's own
3" disk format was used on the Spectrum +3.