20 Nov
2017
20 Nov
'17
4:38 a.m.
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