Spectrum storage solutions

First appeared in Micro Mart issues 820 & 821 (Oct 2004)
Reprinted in ZXF issue 9 (Christmas 2004)

Cassette tape

Think ZX Spectrum and memories of loading in games from a tape recorder won't be far away. Oh, what fun we had back then. The wait... the noise... the crash... the rewind... the sheer and utter frustration. And yet, over twenty years later, the subject of transferring 48K's worth of colour-clashed shoot-em-up from an audio cassette to an over-heated Spectrum is still a focus for genuinely fond discussion within the community.

Why the fascination with tape loading? Simple: cassettes could be copied, and you didn't need expensive equipment to do it with. Such was the prevalence of cheap, tape-to-tape midi systems in the 80s, copying games was just so easy there was no way it was never going to happen. Games were practically hard currency in the playground, which meant they were a way of making friends. And since making and keeping friends is basically what teenage life is all about, it therefore happened quite a bit.

Loading a brand new, fresh-out-of-the-shrink-wrap game into your Spectrum was one thing, but loading a third generation copy of  Bounty Bob from an over-stuffed C90 was altogether quite another. Such was the ubiquity, therefore, of the 'R Tape Loading Error' message within the Shared Spectrum Experience that practically a whole sub-culture grew around the art of getting games to load in. In recent years it's even been suggested that a mystical aura surrounds the Spectrum whilst a game is loading and that this field can be disrupted by anything from next door's Hoover to your mother entering the room to simply not looking at the computer enough...

Looped tape

In the year following the Spectrum's launch Sinclair Research released the Interface 1 (IF1) and Microdrive expansion system; the former an interface styled in the same curves of the Spectrum that screwed into the base of the machine, the latter a looped tape system not entirely dissimilar to the old eight track music cartridges. The added functionality of these devices was 'phase two' of the Spectrum's planned development, giving life to the previously redundant drive commands (CAT, FORMAT and so on) printed below the Spectrum's number keys.

Microdrive cartridges  were tiny: 30x42x5mm; they contained 15m of 1.9mm tape driven by a rather noisy little motor at the breakneck speed of about two metres per second. They could typically store between 90 and 100KB of data, of which 6K could be loaded in close to four seconds. And up to eight drives could be connected at once via the IF1, giving a total online storage capacity of nearly 800KB. These were Sinclair's on-the-cheap answer to the much more expensive floppy disk systems of the day, although compared to disk systems they were inferior in many ways and it's probably more appropriate to think of them as an advanced tape system.

Microdrives were notoriously unreliable. Tape that thin moving at that speed was unlikely to last forever - even the manual cautioned against expecting this - but also early cartridge design placed the rough bits from the moulding process on the inside of the cartridge case to make it look better, giving the high speed tape something pointy to catch and snag on. Not good. Nonetheless, Sinclair staked a lot on the Microdrive system, using a slightly modified version for his QL computer also. The format received extremely limited support from software developers, however, and after the sale of Sinclair computers to Amstrad it was effectively killed off.

An alternative looped tape system for the Spectrum was the Rotronics Wafadrive , an all-in-one double drive unit that accepted cartridges in 16K, 64K and 128K versions (access time decreased with capacity). Although it was slower at loading in data than the Microdrive, its lower data density made it a more reliable system and its syntax was much friendlier than the horrendous IF1 commands. But its fatal flaw was probably its consumption of 2K of the Spectrum's RAM, making it incompatible with many 48K programs. The drives didn't sell well and Rotronics went bust in 1986.

Disk drives

In 1987 Amstrad released the first and only Spectrum to feature a built-in disk drive - the Spectrum +3 . It used a 3 inch drive system capable of storing 180k per side (you had to take the disk out and turn it over); an improvement on cassette tape, for sure, but if you already owned a Spectrum there were plenty of other options.

Broadly speaking, add-on disk drive systems for the ZX Spectrum came in two varieties. There were the all-in-one systems such as the Opus Discovery and the Timex, where your £200 or so (about twice the price of the looped tape systems looked at last week) bought you an interface and drive all wrapped up in a fancy case. And there were the Shugart compatible interfaces that left it up to you to supply a disk drive. Of the latter category, the most well known are probably the Disciple / Pus D from MGT and the Beta Disk Interface from Technology Research Ltd, although their fame is for entirely different reasons.

The Disciple, released in early 1987, was an amazing product. Looking very similar to a Sinclair Interface 1 it too sat underneath the Spectrum and it too offered networking facilities and the ability to connect a standard printer (a parallel printer in this case). But instead of connecting to a maximum of eight 100K Microdrives it could connect to two standard disk drives giving potentially up to 1.6 MB of fast access storage. And it also featured a snapshot button for transferring software to disk, dual joystick ports and an inhibit button that would allow you to connect and operate any conflicting hardware you owned. It really was the ultimate Spectrum interface and today on ebay they go for a small fortune. MGT went on to produce the Plus D disk interface (a cut down version of the Disciple, with just the disk drive and printer ports, and a snapshot button) and the wonderful, but ultimately ill-fated Sam Coupé computer.

The Beta Disk interface was released in 1985 and was a much simpler peripheral offering the connection of up to four disk drives and a snapshot button. It didn't do so well in the UK (I've never seen one on ebay), but in Eastern Europe, where it was rapidly copied and built into a number of Spectrum clones, it became as significant as cassette tape was in the UK. Support for the Russian clones in particular continued long after the end of the Spectrum's commercial life over here and this following has contributed greatly to the Spectrum's overall, ongoing longevity. Today, almost all new software for the Spectrum is released either in cassette tape or Beta Disk (TR-DOS) format.

Hard disks and beyond

Of course it doesn't end there. How could it in a community of enthusiasts gifted with the ingenuity so characteristic of the Spectrum and its software? In recent years we have seen hard disk interfaces offering storage capacities previously undreamt of for the Spectrum. There's Garry Lancaster's +3e system, for example - Garry actually rewrote parts of the +3's ROM in order to maximise the use this machine could make of a hard disk, extending +3 DOS commands very significantly (you can download the new ROMs from his website if you have an EPROM blower).

Most recently of all, attention has turned to Compact Flash as a storage medium. Although this offers less overall storage than a modern hard disk at present, it's still ample for the Spectrum and it has the added advantage that the drive itself can be powered from the Spectrum's own power supply - no need for naked hard drives powered by unsightly PC PSUs; the whole thing fits snugly inside a normal plug-in peripheral case not that much bigger than a joystick interface. Sami Vehmaa's ZXCF interface, for example, offers access to CF cards of whatever capacity you want and gives you a whole megabyte of internal memory to play with too. The possibilities these systems offer are amazing and if software writers rise to their challenge there are some very exciting times ahead.