Device driver subtleties

[ron at BRL-TGR.ARPA]

From:      Ron Natalie <ron at BRL-TGR.ARPA>

Sleep is independant of SPL level, as it is stating you wish to give
up the processor and then level of the new context is used.  However
you do state something interesting, you say you are sleeping at interrupt
level.  You can't do that.  There is no guarantee that the guy who did
the sleep will still be valid when the wakeup comes around.

With regard to close().  Generally, people don't care what close returns.
Close is only supposed to fail if the file isn't open.  I don't understand
your question about the write failing.

-Ron