From: Cian O'Sullivan (Cian@logic.bm)
Date: Sat Apr 27 2002 - 11:43:19 EDT
Many thanks to Selden E. Ball, Jr. who for whatever reason was working on a saturday and came up with the info to bail me out quick enough to make my 1pm tee off time. The list has saved us, in particular Selden. Many Many Thanks
Cian O'Sullivan.
Logic Communcations.
Hamilton BERMUDA.
.
Question:
Operating 4.0D, vmunix cant be opened, so I figured the kernel file is corrupt. Fine, So I stick in a 4.0D CD and I try to boot off of it, and it boots up fine, but because the CD is read only I dont know how to manually mount my RAID or NFS partitions to fix the kernel. Further I dont know how to mount it to the RAM disk because it is not a block device.
Further how do I find out what the actual device number is of the root drive from the >>> prompt.
Answer:
First try to restore from the genereic kernel. You can do this by
>>> b -fl i
and then type genvmunix at the prompt.
If that fails, mount from a CD.
When the system is running from CD, the modifiable directories, like /dev,
are in RAM. The following sequence of commands should work:
boot from CD
exit from the install program (option 3)
cd /dev
./MAKEDEV rz?? (where ?? is the appropriate device name)
fsck /dev/rrz???
mount /dev/rz??? /mnt
(Assuming UFS)
However you need the device name and if you dont know this. then
At the >>> prompt, you can type the command SHOW DEVICE
but the names don't necessarily correspond to the rz device names
that Unix uses. It depends on the motherboard design.
DKC0 usually corresponds to rz16, but not always.
(dka0 = rz0, dka100 = rz1, dkb0=rz8, dkb100=rz9, dkc0=rz16, etc)
On newer processors, the command
SHOW *BOOT*
will list all of the parameters conaining the string BOOT,
BOOTDEF_DEV should be set to the name of the boot device
( e.g. DKA0 followed by some other numbers.)
If you watch closely while the CD is booting genvmunix, it'll type the
rz device names of the disks that it detects.
When you run fsck it'll type the name of the last mount point that
the partition was mounted on. "last mounted on /" would be the boot
parttion, for example. Again, this is for UFS. We don't use AdvFS here,
so I don't recall the command that corresponds to fsck for it.
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