disk formatted - no defect list

[Bob Gibson]

Machine:	Sun 4/330
OS:		SunOS 4.0.3
Disk:		CDC Wren IV (94171-344)
Controller:	Internal SCSI

The problem:

We have a bad block in the /usr partition of this disk.  The "repair"
facility of format(8) wants to read the "current defect list" from the
disk.  This was a replacement disk from Sun.  For some reason, it doesn't
contain one.

The System Administration Manual outlines the following three methods
for (re)creating a defect list:

	(1) "load" one from a file that was previously "dump"ed to
	(2) "extract" one from the disk
	(3) enter the defects manually with "add"

Since this disk never contained a defect list, one was never "dump"ed.  My
attempt to "extract" one from the disk resulted in the message "Extraction
failed" with no explanation.  This leaves me with door number (3).  The
"original" command reports 45 original bad blocks, but I assume I can't
create my defect list soley from these since there may have been more
encountered during the original format.  I figure I have to use "analyze"
to find them all, "add" to build the working list, "commit" to set
"current" from "working", and "backup" to write "current" to disk.  Is
this correct?

The "commit" command warns that the disk must be reformatted for the
changes to take effect.  The manual claims that individual portions of the
disk can be formatted so presumably I can reformat only the bad spots.  Is
it necessary to reformat for all of them, or just the new one?  I would
like to avoid reformatting the entire partition if possible since
restoring it will be a pain.  On a related note, is it reasonably safe to
do the format in single user mode, or do I have to do it across the net
via MUNIX?

Anyone care to share their wisdom on this?  I have the bad block isolated
in a file, but dump(8) won't let me dump this filesystem until I take care
of this.

Thanks in advance,
Bob Gibson	Internet: rjg at sq.com
SoftQuad Inc.	UUCP:	  ...!utzoo!sq!rjg