I'm a fair designer, but could use a hand at parts selection, to build a device to suck data off an old rotating memory. Generally-speaking, I need a little box (black box) that can slurp serial data off five parallel serial streams, synchronously. The native data rate is 80KHz, there are 128 sectors (sector = 32-bit word) per track, 4096 bits/track. Our previous discussion imposing 16X (say) sample rate on 12.5uS/bit is 1.28Msamples/sec, five channels. 4 bits vertically seems adequate. All five tracks must be sampled at the same time; internal machine timing is derived by random logic hung off the timing tracks. Channel-to-channel skew or offset would render the data worthless. Can't read one track, then the next, etc. (That said, it would be possible, if troublesome, to read only two channels at a time, where one channel is always the clock track, but that presupposes the clock track is perfect. I think with all five simultanously sampled I could "fix" a glitch in the clock track and re-write it, but that process will degrade if not simultaneous. I don't think the hardware savings are worth it.) With that assumption, it's 65536 samples/track, five tracks. With a trivial architecture of one 4-bit sample stored per memory byte, it's 320K bytes. Seeing how even little SBCs have a megabyte this will do. As I see it, my two practical (read: lazy) choices are build something around a little SBC, or some kludge around a "PC". The SBC approach: There are many $99 single board computers, many with A/D, but most of them are obsessed with bit depth (10 to 16) and not samples/sec in the lower-cost range. But sticking a five 4-bit ADCs on parallel ports, and every sample-interval, strobing all ADCs and reading 5 nybbles/bytes into local RAM, and a separate command to dump sampled data to a PC via serial port. The PC approach is to somehow wangle the five ADCs into the PC such that it will accept the 65536 5-byte (5-nybble) samples with ZERO LATENCY. There's plenty of memory, but my guess is simply adapting 5 ADCs onto the PC parallel port, or funny hardware to talk USB (and I don't think USB will guarnetee me my latency) is as much work as the SBC solution, which, if coded in assembly, will be plenty fast enough and trivial to build (and easy to test). I favor the SBC approach, as it would make a useful tool for others and it's platform independent. I can't find 4-bit flash ADCs! The smallest ADC on digikey is 8 bits, which is of course fine, but Analog Device's idea of fast is 2.5uS conversion, and they're $15/each. Anyone know of 4-bit ADCs? Or am I barking up the wrong tree here?