[mtools] Re: 'mformat' .vs. 'mkfs.vfat' on 230Mb MO

[Alec Voropay]

Hi!

 Yes, I agree about SCSI.

 There is no partition table on MO, so it is impossible
to determine geometry from disk BPB.

 Unfortunately, 'mkfs.vfat' has no options to setup
C/H/S manually.

 This is possible to define geometry in 'mformat' via
/etc/mtools.conf
=====
drive m:
        file="/dev/sdc"
        cylinders=17853 heads=1 sectors=25
        mformat_only
=====

 One bad thing in 'mformat' is incorrect Media Descriptor
Byte. Factory formatted media has 0xf8 there.

 However, AFAIK 128Mb and 230Mb MO Medias _has_ the
real geometry (to confom ECMA-145 and ISO 13963 [??])
Heads=1 , Sectors=25

 Unfortunately, I can't find full spec, only
brochures from Varbatim and BASF :
http://www.verbatim.com/products/images/90545.pdf
http://products.emtec-group.com/Media/20300/application/pdf/info/

--
-=AV=-

-----Original Message-----
From: Hodek Roman [mailto:address@hidden
Sent: Wednesday, January 29, 2003 7:28 PM
To: address@hidden
Cc: address@hidden; address@hidden
Subject: Re: 'mformat' .vs. 'mkfs.vfat' on 230Mb MO



> It seems, I have found the source of difference. Nor 'mformat' nor
> 'mksfs.vfat' can't determine _real_ Geometry of SCSI MO.

Sure... it's a SCSI disk, so it has no geometry. C/H/S geometries have
been invented by ancient IDE and PC BIOSes, SCSI never had that
concept and used the same thing known als LBA in the IDE world from
the beginning... :)

But the SCSI host adapter driver has to report a geometry, so it
either reports some default one, or tries to determine it from the
partition table, or something else... But it never can be a real
geometry.

> It seems, it's more close to reality (no geometry translation), the
> real Fujitsu drive has only _1_ head. :-)

There's no such thing as a "real geometry", even for IDE disks (at
least ones not older than 8 years). All of them use a different number
of sectors depending on the track number, but hide that from the
interface. But IDE drives were forced to report some geometry by the
ATA interface. But also this geometry is virtual (though software
can't tell the difference...)


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