Homebrew Drum Computer (tape loop)

Mr Ian Primus wrote: The other problem you have with tape even with acceptable delay between the bits appearing is that you want to do a write after read. Say you shift in a value from the read head, process it and need to write it back over the previously read location. with a drum you can have a write head and a read head and have them synced to either a timing track, or a tach disk or other device and have a pretty precise pulse when you read and when you need to write. but with tape, you'd have to be able to get the read and write heads precisely set so that if you wanted to write a value, you'd put it down on the tape over the previous position. I guess the other obvious solution to that problem would be to read everything into a register, and then write it for later retrieval, whether it was modified or not. writing all the time like that doesn't appeal to me but it would work. main thing that would kill you would be the latency of how long till the bits reappeared. I know that one of the attributes of the drum on the lgp30 that was taken advantage of was the fact that there was skew between tracks that one could write modified values to on other tracks, and you'd juggle between several tracks at different radial positions knowing you'd not wait a whole rotation to dispose of the data you needed to save, and could calculate at faster than the drum's rotation latencey. With only a few tracks and a very long time between appearances of data that would be pretty useless. Jim