At 08:36 PM 1/25/2003 +1000, Andy Farkas wrote:

>Greetings Vaxenfolk.
>
>I have a uVAX 2000 with a genuine RD54 disk in it. Its obviously quite old
>but it still works. I know it has some bad blocks on it, because the label
>says so :)
>
>But after running the builtin ROM formatter over it a few times, which I
>assumed would populate the Replacement Block Table, I still get read/write
>errors when dd'ing /dev/zero to it.

The ROM formatter simply reads the bad block map and formats around it. If 
you want to update the bad block map you have to run the VERIFY command 
which is part of the MicroVAX Diagnostics kit. You Boot the DIAG tape, and 
navigate to the field service menu for disk block management, I believe you 
can enter them blocks manually by track, head, offset, or do the scanning 
process. Typically preventative maintenance on these things was :
         Backup system:
         Scan for blocks
         Re-format
         Restore System

This knocked out blocks that had developed, re-layed out the files for 
optimal reading, and generally kept your VAX in tip top shape. If the error 
count was too high you were expected to swap out the RD54 for a new one.

As for the cost on Ebay. Yup, they are expensive but mostly because a lot 
of PDP-11 systems use them. This is the largest disk an RQDX3 can use and 
for a number a PDP-11's they are more reliable than RM03's and the follow 
ons (not to mention much much smaller)

--Chuck