LP-ROM: an impractical open-source project suggestion

I thought of this in the car, on the way to work this morning. Partly inspired by picking up a copy of the UK magazine Linux Format (a well-composed Linux and open source-friendly magazine appropriate for rank beginners through moderately advanced folks).

Way back in the day, Commodore 64 computers (and others) used cassette tape drives to store data. My daydreamy thought: why not develop a LP-ROM drive? It has MAJOR Geek factor, and would even have a rudimentary random-access component -- just pick up the tone arm and move it to the "track" representing the file you want.

A brief websearch for cassette tape drives (after some unfruitful leads) indicates that:

[T]he typical encoding method was simple FSK which resulted typical data rates 500 to 2000 bit/s, although some games used special faster loading routines, up to around 4000 bit/s. A rate of 2000 bit/s equates to a capacity of around 660 kilobytes per side of a 90 minute tape.

From what I remember from copying my used record store LPs to 60 minute tapes, one side of a LP (played at 33-1/3 rpm) fit on about two-thirds of a side of the tape: so, about 20 minutes per LP side. Based on the above figures of 2,000 bps, that's about 293kb per LP side; at 4,000bps, that's around 587kb per side --half a MB!!! And around a full Meg if you use both sides!

Now, I don’t know if the website's figure for cassette tape capacity reflects writing in mono or stereo. If it reflects mono, then writing in stereo would double the capacity. Alternatively, stereo capacity would allow for a simple form of error-checking – to compensate for dust and surface scratches -- with each bit on one stereo channel mirrored at a two-second delay on the other channel.

Some DJs have LP-writing equipment in their studios, and commerical record-pressing houses still exist -- so the equipment still exists. A regular phonograph player, with the line outputs jacked into your PC, would serve as the "drive."


Soooo cool!!! :)

--GG