DOS feature on formatting disk

From: Dwight K. Elvey <dwight.elvey_at_amd.com>
Date: Tue Jan 18 18:15:29 2005

Hi Gordon
 There are a number of possibles but the track 0 sensor
doesn't effect the incremental stepping mechanism used
in these drives. There is no way that it can be off without
being completely off and head over the wrong track.
One full increment of the step is one track.
This is not possible in DOS because it needs to read
the headers correctly to write. It is writing so I'd
guess it is more likely not a full step issue as would be
caused by the track 0 sensor.
 Anyway, I suspect that by the sound that the unit makes,
compared to a good one is that the head assembly is somehow
loose or warn. It is not positioning solidly and cross writing
the other tracks.
 All this is academic since getting inside this laptop to the
level needed to repair the drive is more than it is worth.
This is the unit with the failing video ( one bus bit missing ).
Once I get the data off it, I may not do anything else
with it. I'm even considering just transferring the hard drive.
That is also major surgery on this laptop ( I know because
I put an oversized [ byte wise ] drive in there myself ).
These things were never intended to be taken apart.
 I'm mostly pissed because the stupid format command. The drive
messes up about every third or fourth transfer. In only
about 1/3 of those cases does it trash track 0. I then just
use the magnet. Still, I see little reason why it needs
to see anything on track 0 if it is doing an unconditional
format. You'd think it would just step to track 0 by the
sensor and format it. It would then look to see if it was OK.
Dwight


>From: "Gordon JC Pearce" <gordon_at_gjcp.net>
>
>Dwight K. Elvey wrote:
>
>> Sure but what about not reading track 0 before formatting
>> means it should abort the formatting without first doing
>> a low level format of that track. It is just stupid.
>> If I completely erase the track, it formats just fine.
>> As Sellam says, it is just stupid design.
>> Dwight
>
>I'll bet you'll find that the drive isn't seeking back to track zero
>correctly. All other tracks will be OK but there will be a small
>buildup of shite on the slider knocking the head a tiny bit "inside" the
>proper place for track zero.
>
>What this means is that it partially overwrites track zero, and rewrites
>a new one. But there will be a certain amount of interference between
>the two tracks, and it will not successfully read.
>
>Gordon.
>
Received on Tue Jan 18 2005 - 18:15:29 GMT