On 3/22/07, David Betz <dbetz at xlisper.com> wrote:
I have a MicroVAX II that is able to boot into Ultrix
4.3 single user
mode. If I type "mount" it says that /dev/ra0a is mounted on /. I
assume that is my ESDI hard drive since the drives plugged into my
SDC-RQD11-EC ESDI controller are the only ones plugged into my
system. So, my question is, what would the second drive on that
controller be called? Would it be /dev/ra0b or /dev/ra1a? In other
words, what do the "0" and "a" parts of the device name mean? Is
"0"
the controller and "a" the device on that controller?
With BSDish nomenclature, the 'ra' is the radriver (MSCP), the digit
is the drive unit number, and the letter is the partition. The first
partition is 'a', and for a booted disk, it'll be '/'. The second
partition is 'b', commonly the swap partition, 'c' is the whole disk,
and other letters have other traditional uses, but they aren't set in
stone.
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/disk-organization…
If I'm remembering correctly, we used to arrange Ultrix/BSDish machines like...
ra0a - /
ra0b - swap
ra0d - /usr
ra0g - /usr/users (before home dirs started appearing in /home).
If you started adding other drives, you might mount /usr/users on its
own drive (ra1c, say, for the entire disk), then use ra0g or a
combination of ra0e and ra0f for /tmp or /var or /var/spool, to help
lower the risk of unpriv'ed processes from filling up /, which is a
very, very bad thing.
I also have a TD Systems Viking SCSI controller in the
system with a
CD-ROM drive attached. What device name would I use for that? I'd
also like to know how to address that drive from the MVII boot prompt
so that I can boot directly off of the CD-ROM.
Hmm... I never used a CD-ROM under Ultrix, so I can't be sure what
slice you'd use (if any), but if the CD-ROM is on a different
controller than the boot drive, the second letter should get bumped
up, so if you booted ra0a, the CD-ROM drive might be rb0, but I
suppose it depends. I also have limited experience with multiple
drive controllers in the same box - we had small installations with
typically one large drive controller (MSCP or ESDI or RK611), and
probably one small drive controller (RL11), some number of
communications ports, sync and async, and that's about it.
ISTR there are multiple ways of building device names under BSDish
flavors of UNIX, so my memories of Ultrix might be fuzzing over into
memories of 4BSD and SunOS, if there are any variations. System V,
like Solaris 2, uses a clearer scheme c0t0d0s0 for "controller 0,
target (like SCSI address) 0, disk (like SCSI LUN) 0, slice
(partition) 0". Back when Solaris 1 (SunOS) was being eclipsed by
Solaris 2.0, I remember some grumbling about how verbose the scheme
is, but on the bright side, it requires less deep understanding to
read than "ra0d" vs "rc3g", etc.
-ethan