patching bad sectors on a uda50 drive

[Matt Crawford]

Add this to your dumpstoppers notebook, boys and girls.

The program which can forward individual bad sectors on a uda50
drive is officially known as EVRLK and unofficially as
"scrubber" among the techs.  It was formerly known as "rabads".
It appears on the rev 24 diagnostic tape, and most FEs have no
experience with it.

Caveat: by default, EVRLK will write a forced error (FER) on the
replacement block.  This seems to be the reason that the program
warns you severely to do a backup before and a restore after
using the program.  If your goal is to avoid dump/format/restore
you should answer "No" to the prompt "Enable write with forced
errors", avoiding the FER mark and allowing you to attempt to
clean up the disk with fsck after your bad sectors have been
forwarded.

Disclaimer: any time you patch the raw disk you are risking
death at the hands of angry users!
_____________________________________________________
Matt		University	crawford at anl-mcs.arpa
Crawford	of Chicago	ihnp4!oddjob!matt