RL02-USB Controller Status/Problem

Pete Turnbull pete at dunnington.plus.com
Tue Apr 7 12:21:53 CDT 2015

On 07/04/2015 16:59, Johnny Billquist wrote:
> You are thinking of/referring to how the file system works. The bad
> block list on the last track is not directly used by the system, since
> this is different from one device to the next.
> RL drives have bad block information on the last track. It is not OS
> dependent.

No, but how it's used is possibly OS dependent, as I wrote.  As far as I 
can tell, only the /manufacturing/ bad block data is stored in the last 
track.  RT-11 copies that to the home block, merged with any other bad 
block information found later, and uses what's in the home block.  That 
means whatever reads or writes the disk has to fetch the bad block data 
from the home block (the DL.SYS driver stores that in memory while it's 
resident, and updates it when it knows a pack is changed).  Of course 
here we're only talking about RL01/02 and other drives that have such a 

Maybe it's different for RSX; I don't know enough about the innards of 
RSX to say, hence my question, "RSX-11 may not be the same?"  But I 
think Paul has provided me the answer.


Pete Turnbull

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