george@cornell.UUCP (George R. Boyce) (12/05/85)
This is actually a hardware question which I assume is independent of the operating system... But I'll word it in Un*x terms. The documentation on page 2-6 of the 630QB (MicroVAX II) tech manual says that the primary bootstrap program "searches in order of increasing unit number for a bootable unit...". Now I assumed that means it should *stop* when it finds one but this does not seem to be the case. Since 'newfs' by default puts a bootstrap onto section a of a disk, I had my systems trying to boot from ra2a and failing until one day I placed the boot program into the root file system on ra2a. Now I know *why* all the documentation says you *have* to type 'B DUA0' at the '>>>' prompt. I quickly used 'installboot' (from a BSD4.2 distribution) to copy from /dev/null to the bootstrap areas on ra1a and ra2a. Only then did my systems reboot automatically (or with a 'B' command at the console prompt). Question, is this a bug? It certainly seems so. How do I set up an alternate root file system from which the system boots automatically if the primary disk (ra0) goes offline? It would seem like I would have to exchange the file systems on ra0 and ra2 but Ultrix treats ra0 in a special way, right? I asked this of the colorado support people and the last thing I heard the guy mumble was that it would be a couple of weeks before he got back an "i dunno" answer from the guys "back east". Well, it has been a couple of weeks and I've not heard back from csc...
dave@uwvax.UUCP (Dave Cohrs) (12/06/85)
> The documentation on page 2-6 of the 630QB (MicroVAX II) tech manual > says that the primary bootstrap program "searches in order of > increasing unit number for a bootable unit...". I'm not sure about the manual, but what seems to happen in real life is that the floppies get searched first (if you have floppies) and then the hard disk. I assume this is done to help users run diagnostics without knowing what is going on. -- Dave Cohrs (608) 262-1204 ...!{harvard,ihnp4,seismo,topaz}!uwvax!dave dave@romano.wisc.edu