7 Apr
2015
7 Apr
'15
12:01 p.m.
On 2015-04-07 19:21, Pete Turnbull wrote:
On 07/04/2015 16:59, Johnny Billquist wrote:
How it is used is definitely OS dependent, but the information is as I
described.
See "RL01 RL02 Disk Subsystem Users Guide".
Section 1.5 Bad Sector File, page 1-6 to 1-8.
(http://bitsavers.trailing-edge.com/pdf/dec/disc/rl01_rl02/EK-RL012-UG-004_R…)
5 copies of the factory written bad sector info, and 5 copies of the
field written bad sector info.
Now, RT-11 might not be using the information right, I wouldn't know. I
think that any Unix system definitely did not use the information right.
Johnny
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
table.
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.