SUMMARY: Bad magic number

From: Marcello Frutig (
Date: Tue Sep 03 1991 - 12:22:59 CDT


I posted a message asking about the following messages :

          Bad magic number in disk label!
          The file just loaded does not appear to be executable.

I received some responses, but I discoverd that the Sun had a bad fuse !
I just replaced it and everything became fine...

BTW, here are the replies :

1. If the disk is stuck try power up the system while giving the disk a good

2. Boot up the miniroot to reinstall the boot block :

        b sd(0,0,1) vmunix -sw #minirooot
        mount /dev/sd0a /a # mount up root partition
        cd /usr/mdec
        ./installboot -vlt /a/boot bootsd /dev/rsd0a

   The boot block contains the disk label (describes the geometry of the disk)
   and the disk partition table (describes where to find the partitions).

3. If it's not a sick device controller or anything else with the disk,
   run the format utility to relabel it, seeing before if the format
   backup command can find a copy of the old label. Caution : relabelling
   a disk from scratch will lose old partitions.
4. If the disk is a large one (more than 2**21 sectors), there is a SCSI
   addressing problem. There is a bug in the SunOS SCSI driver : access to
   sector (2**21 + N) wraps around to sector N. Solution : boot MUNIX and
   miniroot from tape and fix up the partitions tables with format if you
   are using too many sectors.

5. If it's a new drive without a installed driver, format the disk using values
   supplied by the vendor.

6. Maybe, you forgot to run installboot after regenerating a new root
   filesystem or installing a new /boot, or even you ran installboot on the
   wrong system.

7. And finally, if anything above can't resolve your problem, maybe you have
   to replace the disk !

Thanks to :

Dana Fagerstrom <> (alex;923-4483) (Daniel Strick)
"Matt Crawford" <> ( Bob Rutherford 965-0546 ) (Mark Seiden) (Stan Sawyer)
ccrwest!kkw@UCSD.EDU (Kandi Kirk-Wilt)

 Marcello Frutig E-Mail :
 Network Manager Voice : +55 21 529 9422
 Catholic University of Rio de Janeiro - BRAZIL

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