Mailinglist Archive: opensuse (946 mails)

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Re: [opensuse] WD Green AV HD: rsync read errors mapping
On 2017-09-03 21:51, Knurpht - Gertjan Lettink wrote:
Op zondag 3 september 2017 15:36:52 CEST schreef Carlos E. R.:
On 2017-09-03 14:30, Anton Aylward wrote:
On 02/09/17 06:01 AM, Carlos E. R. wrote:

So I prefer to use badblocks. I have also noticed that, in my cases, and
a few others I read about, it failed to find the bad sectors that the
long SMART test said existed. Running smartctl again it also failed to
find those sectors, so the empirical guess is that it can cause "repair"
of sectors transparently.

In my SystemV Unix days finding badblocks on a 600 MB disk meant call NCR and
have it replaced, then restore a backup from tape. But that took about four
five hours. The SLA from NCR did simply not allow us to proceed with a disk
that had ( just one or a couple of ) badblocks.

Back on my MsDOS days, initially we had hard disks with steppers motors
for the head (currently they use "voice coils"), and capacities of
10..32 megs. Yes, MBytes. Those disks came with a paper label listing
known defects, ie, sectors known to the manufacturer to be bad!

We had to initialize the disk with code that run from the bios, using
debug. I think we just told the thing to start running from a certain
address, probably residing inside the hard disk controller. As data, we
had to enter the interleave and the defect list.

An interleave of three meant that after sector #1 came two other
sectors, then (IIRC) sector #2; ie, while the computer processed sector
#1 the disk had time to continue rotating, and it would get to sector #2
just as the cpu was ready for it, after skipping two other sectors.
Setting no interleave would mean that when the cpu was ready for #2, the
disk head would be at #4, thus having to rotate one full turn more
before reaching #1 again. On my computer I think I needed an interleave
of 13. Yes, I tested and timed all numbers from 1 to 13.

That was "low level format".

Later came the partitioning and the formatting.

Having seen that, the paper label with the list of bad sectors, I do not
consider some bad blocks as final :-) . The important thing, to me, is
that the list doesn't grow.

Also, MsDOS could mark a sector as bad in the FAT. Some Linux filesystem
can do that, others could not, at least initially (eg, reiserfs).

Cheers / Saludos,

Carlos E. R.
(from 42.2 x86_64 "Malachite" at Telcontar)

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