[semi-OT] QIC2 streaming cartridge tape lossage

[Michael ODonnell]

>> Nice how the 9-track serpentine
>> layout makes it possible for a single medium flaw to trash the bit stream
>> in 9 different places at once...   >-/
>
>  Unfortunately, I think most tape systems are multi-track --
>everything from ancient reel-to-reel stuff to the latest LTO.

Right, but formats like reel-to-reel (you know, the ones they showed
spinning in old timey movies & TV to indicate awesome computing power?)
were 9-track parallel.  QIC2 used 9-track serpentine, meaning the bits
were layed down serially on one "track" and when End-Of-Tape was reached
in one direction they'd move the head so it was over a new track and
start the tape back in the other direction, again and again as often as
as 9 times.  So my point is that a single flaw in the tape wouldn't just
trash your stream of 9 parallel bits at one point but trash your single
serial bit stream in as many as 9 places.  Think of a scratch in an LP.

I knew all this at the time but since I'd only occasionally seen tapes
be unreadable when pulled from storage I thought I'd chance it.  I didn't
realize their half-life was so short...


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