[TUHS] Determining what was on a tape back in the day

[Lyndon Nerenberg]

> The early Sun boxes used to hang when rewinding the cartridge tape, because 
> the controller didn't release the Multibus; the stingy Lionel Singer used to 
> sell the 3/50 as cheap servers...

The Convergent Tech MiniFrame had a similar bug with the QIC tape drive. 
If you sent it an interrupt during a rewind (e.g. ^C a cpio after the 
extract was done, but before the rewind/close finished), it would block 
the tape device from any further use.

That was my first expedition into non-API UNIX kernel hacking, writing a 
program that would reach into the kernel to clear the 'busy' bit on the 
tape device.

--lyndon