7 Apr
2015
7 Apr
'15
12:58 p.m.
On Apr 7, 2015, at 3:25 PM, Johnny Billquist <bqt
at update.uu.se> wrote:
On 2015-04-07 20:54, Pete Turnbull wrote:
Not necessarily. I don?t know the RT11 details, but suppose it works this way: a few
blocks at the end are spares. All good blocks have their native address. All bad blocks
are redirected to one of the spares.
If so, some other file system, one that avoids the bad blocks, will work fine. All good
blocks are where expected. The bad blocks aren?t, but those aren?t in use. The only
trouble would be if the spare region is actually used for data. If it?s free, then you?re
basically ok.
paul
On 07/04/2015 19:26, Johnny Billquist wrote:
Well, no, actually; I've been using it (under RT-11 V5.7) to copy other
OS disks (mainly 7th Edition Unix) because it does that perfectly well
:-) When the DL.SYS driver sees a disk changed, it reads the
manufacturing defect list so it's still good to copy most disks.
But since the 7th edition Unix most likely do not treat the bad blocks the same way as
RT-11 does (skipping bad blocks), that means blocks will get renumbered, and 7th edition
will end up with a very corrupt and broken file system.
Essentially, this will only work well if you don't have any bad blocks on the device.
Well,
yes, it's still bad, and still there, but all the RT-11 utilities
use the substitute block.
So COPY/DEV is essentially only usable for opying RT-11 disks on RT-11
systems. :-)
Nothing wrong with that, mind you.