[robespierre]

I've never seen "defect list error" up to now, but it would appear to be consistent with a disk that accumulated so many bad sectors that its defect list got filled up. If this is the case, there is no point in using that disk any more.
One proviso to the above is that the entries in the defect list are not always genuine defects. The SCSI protocol defines four types of defect lists:
PLIST : The list of defects that are considered permanent defects. This is stored into the drive at the factory after the factory surface test. This is a read-only list: it never changes after the drive leaves the factory.
DLIST : The list of defects sent by host software to the drive to be added to the GLIST during a FORMAT UNIT operation. These defects are "manually added" from the drive's perspective.
CLIST : The drive can optionally perform a certification procedure while executing the FORMAT UNIT command. Defects found by the drive during certification are added to the CLIST, which gets added to the GLIST.
GLIST : The list of "grown defects", which are all those defects which have been added since manufacture. The GLIST is added to either automatically, or by the REASSIGN BLOCKS or FORMAT UNIT commands.

If the drive is operated under some marginal conditions, for example with bad cabling, it is possible for communication errors with the host computer to reflect as block errors and defects. So the GLIST may be filled up with fake defects, impeding correct operation. I wrote about this problem at https://forums.irixnet.org/thread-3046-p...l#pid21459

(As an aside, if your drive parameters are set to "DO auto bad block reallocation on read" you may have triggered this problem. I notice in your screenshot #7 this is turned on.)

The drive may be reformatted to clear the grown defect list. This is not possible using fx, but it can be achieved through a short C program in IRIX. But until that is done you will definitely not be able to install IRIX on that disk. It may also not help, if the drive is so worn out that it was filled up with genuine defects.