Hard Disk problems

[Tony Cooper]

This is my first posting from a new news program. It is a UNIX system so it
should be a good deal more reliable than the Vax/VMS system I was using. I
posted some other articles last week from a Vax and they never made it.

The way to mount an HFS volume is to mount it under MacOS first. Then, and
only then, boot A/UX. A/UX will only mount the first HFS partition on a
disk. And then ONLY when it was mounted under MacOS first.

When you have problems mounting HFS volumes here is how you can diagnose 
what is wrong. If your SCSI id is x then do (as root)

dp /dev/rdsk/cxd0s31

This will either work or it won't. If it works then you will end up with a
prompt and you type in P. It will list all your partitions. Have a look
for the HFS partition(s) which are indicated by Type: "Apple_HFS". The
first such partition listed is the one that A/UX will try to mount. Study
it's parameters to see if they are reasonable and to see if the partition
is the right one. You will have to figure that out for yourself. Read dp(1m)
to see what the fields mean.

If dp does not work then you have no chance of mounting the HFS volume. 
What you do depends on the error message dp gives (maybe the drive is not
switched on, maybe the partition table is wrong). If the partition table
is wrong then your drive formatting software is out of date. If the drive
is not switched on then switch it on.

If dp works then the next step is to do as root 

dd in=/dev/rdsk/cxd0s30 count=1 | od -c

You should get LK as the first two bytes. Then the MacOS boot block info
some of which is words like Finder and Macsbug and dissasembler. If you
don't get this then there is not a valid HFS filesystem in the first
HFS partition. Something is wrong somewhere - maybe with your disk
partitioning software.

If this works then I have no idea what to do next. It should work. You
can try force mounting the partition with HFSmount. Type

HFSmount /dev/dsk/cxd0s30

and see what happens. You have to get a copy of HFSmount first. It hasn't
been released yet. Just wait till I have tested it thoroughly under 
A/UX 2.0.1. Something else you can try is

HFSmount

With no arguments it mounts every HFS partition it can find on your SCSI
bus. If your HFS partition is lurking there somewhere HFSmount will find
it. But don't wait for HFSmount. Your single HFS partition should mount
by itself. I just included this last bit on HFSmount to let people know
it status.

Tony Cooper
sramtrc at albert.dsir.govt.nz