7 Apr
2015
7 Apr
'15
8:59 a.m.
On 2015-04-07 16:58, Pete Turnbull wrote:
On 07/04/2015 11:21, 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.
Johnny
The STD144 reserves the last track of the device
for pack information.
In there you have the pack serial number, and also the manufacturer bad
block list, and also the user bad block list.
While looking for something quite unrelated, I noticed that the RT-11
Device Handlers Manual says slightly differently. The user list is
stored, merged with the manufacturing list, in the home block (track 0
sector 1) of RL01/02 and RK06/07 volumes, beginning at offset 6
(HB.BAD). The actual replacement blocks are reserved space on the
second last track (or tracks 0,1 of the last cylinder on RK06/7).
The symbol names for the values in HB.BAD are defined in the .BBRDF
macro in the distributed file SYSTEM.MLB.
Offset Name Meaning
0 BBR.BD Bad block number.
2 BBR.GD Replacement block number.
BBR.SZ Entry size.
RSX-11 may not be the same?