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Re: a small disk question



On Wed, 9 Jun 1999, Henry Ficher wrote:


Naturally, but you said you were getting a new disk.. So I assumed it wont
be factory formated with ext2fs ;)

--Ariel

> 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 fewercylinders 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?
> 
> 
> 
> 

   +---------------------------------------------------------------+
   | Ariel Biener                                                  |
   | e-mail: ariel@post.tau.ac.il           Work phone: 03-6406086 |
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