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On Tue, Feb 20, 2001 at 11:25:41PM -0800, Gene Buckle wrote: Oh, I forgot to mention I'd forgotten that I have no modern idea? :) OK, let's work this through, and forgive me any bad assumptions, incorrect foundation information, or faulty analysis ;) Because vinyls are fundamentally an audio media[1], we need an audio->digital conversion system. To use modems as a base - v.42 I think is the 33.6k standard?33600bps = 4.2KB/s. This works out to 252KB/minute. What is the audio length of a vinyl? I'm not sure, but if we make a nice round 60 minute, then we're looking at about 15meg. Now, that's not the end of the story. v.42 is designed for modems - duplex. LProms would be a read-only system. Also, the figure of 33300bps is based on a modem audio resolution of 2400baud. I don't know the audio resolution of an LP, but if I had to guess, I'd put the figure as higher than 2400. So we're increasing capacity already. In a similar vein, you could run the LP at 15rpm, rather than the normal 33rpm, to reduce the resolution, while increasing the length. I'm sure there would be an ideal somewhere between those two tradeoffs :) Next up, we look at the modulation/demodulation to use. We'll want a compression that takes best advantage of the medium. (I suspect v.42 is not it!). Lastly, LP's are stereo - so that either immediately doubles our capacity (assuming L and R can be kept 100% independant. If they can't be guaranteed to be kept seperate, then I'm sure capacity could still be increased by using L and R as checksums against each other or something ;) Problems with LProms are quality of reading - you run a very real risk of bitrot if your needle is of poor quality. Also, you'll need some way to sync the end of sideA with the start of sideB - there is some data loss there. (this could probably be kept to a minimum by using the leadin/leadout areas :) So, did I have an answer in all that? I'm pretty sure you'd get 15meg on a vinyl easily, and could quadruple that figure with a bit of effort :) .../Nemo [1] If digital data can be recorded directly to vinyl, and more importantly, read from the vinyl, then this entire analysis is meaningless :)