Your Mother Saves Data on EightTrack Tapes 4372

Al Kossow

Although that hadn't been the original focus of my page, I decided that I would dig among the information I had, much of it from your site, to add as many formats as I could to my site. I've probably found enough of them for now, though...

included is the format for the 3-4" tapes used with the KDF9, for example, which, like DECtape, recorded the data twice on two separate tracks.

Unfortunately, the IBM Research servers are down for annual preventative maintenance on the labor day weekend... I found that out when trying to download an article by Franaszek on his early work with RLL codes. I've been hunting for data as well as I could, but I still haven't found out what the two check bits on Hypertape did. Two check bits with eight data bits aren't enough for a Hamming code with parity (apparently what TRACTOR had)... I'm thinking that one of the tracks was parity, and the other one either longitudinal parity, or diagonal parity (the idea of just XORing both together on one track, as with "Fire codes", of course, came much later), since it is claimed to be able to correct single errors... but attempting to search the patent literature has not yet yielded results.

John Savard