Hi again,
On 26-Feb-00 Kelly Yancey wrote:
> On Sun, 27 Feb 2000, kibbet wrote:
>
>> Hi all,
>>
>> Quick question, how does the new ata driver handle bad blocks?
>> I've been tracking -current since around Nov 99 but haven't
>> seen this come up.
>
> As I recall, it doesn't. The reasoning is that modern IDE drives perform bad
> block reassignment so if you are seeing bad block errors, then the entire
> reserve of blocks available for reassignment has been exhausted. In which
> case, things are Very Bad and you should start backing up your data ASAP.
Yup, no problem, sounds fair. Just read the docs for this drive, it dosent
say anything about bad blocks, but its only a few years old so I'm assuming it
does the fancy bad block assignment. :) (its an IBM DJAA-31700)
No need to backup, I keep it around for this specific reason :)
> In you scenario of upgrading from the old wd driver in -stable to the new ad
> driver in -current, the only advisable action is to just not do a bad block
> scan under -stable before upgrading. The should stop the complaints from the
> ad driver about the old-style bad block table.
The new ad driver dosen't seem to complain at all if I've bad block scanned
when installing -stable (infact I can't install -stable if I haven't block
scanned the drive). The (-current) ad and wd drivers just seem to ignore the
fact the drive had been scanned. The problem arises when I use bad144 on
-current, rather than just complaining it actually makes the system unbootable.
eg.;
freebie4# bad144 -s -v ad0
cyl: 3307, tracks: 16, secs: 63, sec/cyl: 1008, start: 0, end: 3334212
bad144: couldn't set disk in "badscan" mode: Operation not supported by device
Block: 1202131 will be marked BAD.
[snip more blocks marked BAD]
Then I reboot, and I get;
ad0: bad sector table not supported
So this raises a few questions;
1: Should bad144 exit without doing anything if it detects a modern drive that
handles its own bad blocks?
2: Should the process of mounting root ignore bad144 info if the drive does its
own bad blocks?
IMHO one of the above should happen, you shouldn't be left with an unmountable
root because you ran bad144 on a drive that dosen't support it.
3: Is it possible (or advisable) to use badd144 info in conjunction with the
drives bad block data? (I've got 21 bad blocks on this drive, which haven't
grown since they appeared, I'd like these blocks to be ignored) - I guess
this would be rather more than just a trivial task :)
4: The $6m question, how do I fix it so I can mount root? :) I have a generic
-stable kernel (so I think I can boot), but I can't find any mention of how
to tell the drive not to use bad144 info.
Anyways, abuse away if I've totally missed the plot :)
Cheers,
Kent Ibbetson
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