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Dedicated to the Sinclair ZX Spectrum

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Sinclair Interface 1 & ZX Microdrive

The beauty of the Sinclair Spectrum, and other home micros at the time, was their ability to store data to standard cassettes. The same cassettes you used to tape song from the radio, and that were cheap and easy to purchase.

The early, small programs and type-ins were very rarely over 10k in size and could be saved and loaded in around 2 minutes, usually less, with some commercial games being just 4k in size.

As the games grew and the available memory moved from 16 to 48k, loading times increased and it wasn’t unusual to be waiting five minutes before you could play your favourite game.

Companies tried to address this using custom, turbo loaders, but this had the knock-on effect of making them difficult to load as the read/write heads of the average tape recorder were not all aligned the same.

The age of disc storage was looming and there were many companies producing their own systems, but the inherent cost, sometimes equal to the computer itself, meant the technology had limited sales. In April 1982, when Sinclair originally revealed the ZX Spectrum, they also announced a new and affordable storage medium, the Microdrive. Its initial description was of a single microfloppy, but as time moved on and the technical issues began to bite, this was changed to single storage medium.

This device saw multiple delays and technical problems before the public finally got their hands on it in September 1983 – only 17 months after it was first announced. The Microdrive required Interface one, which came with the drive in a special package, and could also be bought as an additional units on their own.

Interface 1 was designed to sit underneath the Spectrum, tilting the keyboard to a more comfortable angle. The Microdrive unit plugged into this with a short ribbon cable. The interface 1 also had a pass through port and a network port that was RS232 compatible and Sinclair’s own network port that allowed up to 64 Spectrums to be connected together.

If you wanted you could use the screw to permanently fix the interface to your micro. The interface also allowed up to 8 Microdrive units to be plugged in, if you had the desk space. Early units often overheated, and resulted in a large disfigured patch – like mine. The problem was fixed in later version though.

Once connected and the Spectrum switched on, the commands designed to work with the Microdrive were made available. The cartridges were small, being just 4.5cm long and 3.5 cm wide, and came in a small plastic case. Pulling this off allowed you to see the tape loop, and was necessary before you can plug it in. Once plugged in, you were ready.

The commands were a bit long and convoluted but once you had learnt them, they became second nature. Formatting took around 20 seconds and left you with between 70 and 85k of free space. Saving and loading data, again used long commands, but was still much faster than cassette.

As with the Wafadrive, reviewed in episode 2, any storage device is only as good as the software for it, and although the Microdrive had more than the Wafadrive, there was not wide spread support from software houses, mainly due to the cost of the cartridges.

The other problem for new buyers was transferring your existing collection commercial software. This was difficult due to the protection systems used, even with commercial copiers, things rarely worked for more than one game or two. The most successful method was the Multiface. A small device plugged into the back that allowed any software to be frozen and saved to cartridge. This obviously also meant more cash though, and another device plugged into the back of your computer.

Speed wise, the device proved very fast, and I tested this using the same game I used to test the Wafadrive. Bug-Byte’s The Birds and The Bees. This 32k game take around 2 minutes 25 seconds to load from cassette, having transferred it to microdirve, the time came down to just 20 seconds, which was impressive. The wafadrive could only manage 60 seconds.

When connected, the unit looks great, especially with the rubber-keyed Spectrum, and was high on the list of peripherals for many owners. It came into its own if you developed your own software, loading and saving your work could now be much faster and less error prone.

Sinclair were often criticised for their build quality, but these 30 year old units can still be purchased from eBay in fully working condition. The cartridges though are a different matter, and have a habit of self-destructing. The felt pads that hold the tape in place so that the read/write heads make contact often disintegrate leaving the cartridges useless, with a good chance of the debris collecting inside the drive itself.

Overall then, a great system that should have been brought to market sooner, which in my opinion, would have changed the future of the machine and become the standard storage medium. As it is, being nearly 2 years late, the use of cassettes became fixed and the unit didn’t do as well as it should have. A real pity as I love this device… just sound of it brings back happy memories of late night programming sessions knowing when that wurring noise stopped, you had your data safely stored.