Finding bad blocks, any ideas?

[vandenberg]

Config: IBM RT running AIX w/ ESDI hard drive
Problem: encountering bad blocks that VRM format isn't flagging.   
The Diagnostic format doesn't seem to be working properly w/ the drive.
System runs fine until it encounters bad blocks.  Any ideas or leads 
would greatly be appreciated.
Please reply via email or phone(collect) me(Tom) or Frank @ 414-466-6691
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Tom Vandenberg                {..uunet..uwvax!uwmcsd1..}!marque!studsys!vanden
vanden%studsys at marque.UUCP             {..uwvax..arpa..}!studsys.mu.edu!vanden