The Spectrum was an amazing machine for its price in the early 1980s, but this was achieved at the expense of very little in the way of built-in hardware interfaces beyond its video and cassette ports. The ZX Interface 1 unit, which screwed to the bottom of the Spectrum and engaged with its expansion port.

A maximum of eight drives could be connected in this way. On the front is an opening about 32 mm by 7 mm for the Microdrive cartridges, and on each side at the rear is a 14-way PCB edge connector for connecting to the Spectrum and daisy-chaining to another Microdrive via a custom serial bus over supplied ribbon cables and connectors.

Picking up a Microdrive, it’s a unit about 80 mm by 90 mm by 50 mm weighing just under 200 g, and it follows the same Rich Dickinson styling cues as the original rubber-key Spectrum. This gives me the opportunity to examine and tear down the system, and provide a fascinating insight for readers into this most unusual of peripherals. Idly chatting about the Microdrive, she bought out examples of not only some of the drives and software, but also the interface system and an original boxed Microdrive kit. When 80 kB Of Storage Was A Big Deal The ZX Microdrive unit in all its gloryĪs a traveler returning from a continental hacker camp the UK government requires me to sit out two weeks quarantine due to the pandemic, which I’m doing as the guest of Claire, a friend of mine who also happens to be a fount of knowledge on and prolific collector of 8-bit Sinclair hardware and software. Sinclair owners could take their place alongside the Big Boys of the home computer world, and they could do so without breaking the bank too much. This was a format developed in-house by Sinclair Research that was essentially a miniaturized version of the endless-loop tape carts which had appeared as 8-track Hi-Fi cartridges in the previous decade, and promised lightning fast load times of within a few seconds along with a relatively huge storage capacity of over 80 kB.

If you had a Sinclair Spectrum though, by 1983 you had another option in the form of the unique Sinclair ZX Microdrive. Only the extremely well-heeled could afford a disk drive, so if you didn’t fancy the idea of waiting an eternity for your code to load then you were out of luck.

An enduring memory for most who used the 8-bit home computers of the early 1980s is the use of cassette tapes for program storage.

Dr Zx Software