Richard,

I followed you halfway through - you want to capture a serial stream of what we can see as random data at first glance. It would help if you'd tell us what amount of data are you talking about (how many bits (= heads) at once, and how long are you capturing (how long is a track) at which rate).

However, I got lost where you started mentioning the PC. You don't need to decode this on the fly, do you? What is the "formatter"? Or do you want to use fully those disks with modern PC, not only read old data?

Jan