Dead RF31 DSSI Disk.. final Question..
holm at freibergnet.de
Tue May 12 14:04:56 CDT 2015
Paul Koning wrote:
> > On May 12, 2015, at 1:28 PM, Holm Tiffe <holm at freibergnet.de> wrote:
> >>> ...
> >> The exerciser showed some correctable soft errors, wich is pretty much
> >> normal I think. Reformating the drive should simply "freshen up" the data
> >> tracks but erase should do the same in this regard.
> >> Since the distks aren't containing anything interresting, it would be the
> >> right time now to do a reformat.
> >> I think the head assembly has an voice coil engine anyways, so servo tracks
> >> are needed to do the positioning. It is clear that they aren't affected from
> >> a reformat...
> > Johnny the success proves that I'm right. After "erasing" the disk the
> > exerciser run found no soft read errors anymore. "Soft error read count 0".
> > BTW: This was the disk that I've hammered :-)
> Servo data is unaffected by formatting. If you have read errors, simply overwriting the drive may be sufficient, but certainly formatting would. That assumes such an operation even exists; in some cases, when people say ?format? they simply mean pattern-checking the drive and/or creating a new empty file system on it. For example, in PDP-11 disks, a ?real? format operation that does more than just rewrite the data appears only on a few drive models: RP03 and RK05 do, most others don?t. Some MSCP drives also, I think, but those only via magic code running on the controller, not from the OS.
> On drives with dedicated servo tracks (RP04 family for example) the servo head is only a read head. But in all cases, servo writing is done on specialized machines, and only at the factory.
Yes. Thats similar to that what I wrote above.
In the case of the RFxx Disks, DSSI Disks, you can only run the local to
the drive commands and there isn't any format option. SCSI drives can
(mostly) reformat themselves and possibly with different sector sizes.
But this doesnt affect the servo tracks, that's pretty clear.
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