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Re: a small disk question
BTW, while investigating this I found that tune2fs also uses a -m flag to
specify the percentage of reserved blocks for the super-user, only without
having to format the disk.
___________________
Henry Ficher
ficher@netvision.net.il
ICQ#: 7130104
----- Original Message -----
From: Ariel Biener <ariel@fireball.tau.ac.il>
To: Henry Ficher <ficher@netvision.net.il>
Cc: Constantin Eizner <eizner@research.haifa.ac.il>;
<linux-il@cs.huji.ac.il>
Sent: Tuesday, June 08, 1999 11:22 AM
Subject: Re: a small disk question
> On Tue, 8 Jun 1999, Henry Ficher wrote:
>
>
> Hi,
>
>
>
> First of all, what you said doesn't apply at all for SCSI.
>
> Second, a carefull reading of the mke2fs man page would have revealed
> this:
>
> -m reserved-blocks-percentage
> Specify the percentage of reserved blocks for the
> super-user. This value defaults to 5%.
>
>
> Now, 5% of a 9.2GB disk results in: 460Mbytes
>
> And this is exactly how much was missing from the drive when one did
> `df'.
>
> This is a common problem, I think it was even asked on this list once
> or twice.
>
>
> --Ariel
>
> >
> > Sorry to contradict you, Ariel, but some bioses DO have an 8.4GB
limitation
> > (not 8.3GB as I stated before) . Here's a quote from Western Digital's
> > website (http://www.westerndigital.com/service/FAQ/8-4.html#1):
> >
> >
> > "In order to properly support an 8.4 GB or larger IDE drive, your
system's
> > BIOS must be capable of supporting INT13 Extensions.At this writing,
only
> > a few BIOS's on some (but not all) new systems support these functions."
> >
> > The Large disk HOWTO also mentions BIOS problems:
> >
> > "11.1 BIOS complications
> > As just mentioned, large disks return the geometry C=16383, H=16, S=63
> > independent of the actual size, while the actual size is returned in the
> > value of LBAcapacity. Some BIOSes do not recognize this, and translate
this
> > 16383/16/63 into something with fewer cylinders and more heads, for
example
> > 1024/255/63 or 1027/255/63. So, the kernel must not only recognize the
> > single geometry 16383/16/63, but also all BIOS-mangled versions of it.
Since
> > 2.2.2 this is done correctly (by taking the BIOS idea of H and S, and
> > computing C = capacity/(H*S)). Usually this problem is solved by setting
the
> > disk to Normal in the BIOS setup (or, even better, to None, not
mentioning
> > it at all to the BIOS). If that is impossible because you have to boot
from
> > it or use it also with DOS/Windows, and upgrading to 2.2.2 or later is
not
> > an option, use kernel boot parameters."
> >
> > All this refers to IDE drives, of course. I don't know about SCSI.
> >
> >
> > I read the mke2fs man page but still can't see how it applies. Could you
> > please explain how to figure out the right value for the reserved
percentage
> > for root? Or maybe give me an URL where to read about this?