Probably this
is documented somewhere, but I really need a pointer or a brief tutorial on the
major/minor device numbers for mknod() and the device names for MSCP drives in
2.11bsd.
If I have a
really simple PDP with an RQDXn and one RDxx disk, then the device name is
conventionally /dev/ra0x and the first partition, ra0a is (5,0), the second,
ra0b, is (5,1), etc. Pretty easy.
If I have two
drives on my single RQDXn, then the second hard disk is /dev/ra1 and ra1a is
(5,8), ra1b is (5,9), etc. I guess the offset of 8 must be the
maximum number of partitions on a drive - OK, I'm still with
you.
But what if I
have a second MSCP controller? Assuming that I've built the kernel to
handle it and modified dtab to autoconfigure it, that is. What are the
usual names and mknod() numbers for the drives on the second
controller?
Worse, what
if the MSCP controller isn't a RQDX but is a real UDA/QDA ? Now the drives
have their own MSCP unit numbers that can be anything from 0 to 250 - where does
this figure in?
Same question
for TMSCP - what if I have more than one tape controller? This case is
easier, though, since TMSCP controllers normally have only one drive associated
with them.
Thanks,
Bob
Armstrong