Tape drive out to lunch

[Guy Harris]

> The precision of u.u_error is pretty poor. It should have 'Device busy',
> 'Write protect' and many more to accomodate drivers and to eliminate
> the 'uprintf("No write ring\n");' and other kludges found in some kernels.

True.  The lack of precision in error codes and the lack of enthusiasm by
UNIX programs (and programmers) for actually checking for errors and
printing reasonable messages (i.e., "perror"-style messages, at least) go
hand in hand.  The latter is probably as much a reason for those kludges as
the former (although Multics, if I remember correctly, had better error
codes and a fancier message printer, and its tape driver was amazingly
verbose, spitting out several lines of friendly greetings to let you know it
had opened a tape).

	Guy Harris