"struct pmax_device" to avoid conflict with <sys/device.h>.
Change the signature of interrupt-handlers to take a void *
(a pointer to the softc) and return an int (indicating spurious
interrupts or other conditions.)
pmax conf.c references them. A cut-and-paste job from the pmax
rzwrite() and rzread(). tzwrite() and tzread() are utterly untested.
tzwrite() should also check for write-protect, or handle writes to a
write-protected tape gracefully.
jonathan