bios doesn't like large hard drives

Bry Melvin brymelvin at melvinart.com
Wed Oct 18 04:38:42 BST 2006



--- Rob Blomquist <rob.blomquist at verizon.net> wrote:

> On Tuesday 17 October 2006 07:48, Samuel Debruyn
> wrote:
> >
> > My problem is: this utility only works with
> Windows, when I tried to install
> > Kubuntu, Kubuntu was still showing the EZ-Drive.
> If I delete the ddo, my pc
> > will hang while the BIOS boots the hd. A solution
> to this problem?
> 
> Interesting. I used to have a machine that had an
> oversize drive on an older 
> mobo, and Linux did not care what the BIOS said, it
> just checked with the HD, 
> and found out what it was, and used it.
> 
> I wonder why that is not happening now, and lack the
> time to find out for you.
> 
> Rob
> 
> -- 
> Mountlake Terrace, WA
> 
> -- 
> kubuntu-users mailing list
> kubuntu-users at lists.ubuntu.com
>
https://lists.ubuntu.com/mailman/listinfo/kubuntu-users
> 
I think I can answer the why:
The older bios ALSO had a limitation that the boot
partition had to be IN THE FIRST 1024 cylinders. Once
the boot occurs Linux can use the larger HD. This was
also a factor in OS/2 NT4 and Unix. NT be installed
with a small boot partition, and then a service pack
installed to recognize the rest!

The older versions of Linux and indeed some still,
would use a small boot partition.
 Depending on physical attributes the size of the
first partition on some of these bios may have to be
very small. I remember an early WD 8 gig that had
13000 odd cyl making only a small boot partition
possible. I remeber haveing to have < 250MB once for
an OS/2 boot partition. However /boot doesn't NEED to
be large.

Ubuntu makes a / partition and a swap by default. as
the boot is in the large / partition it doesn't get
recognozed as the partition is > 1024 cylinders.

For this all to work you would need to make /boot a
seperate PRIMARY partition within the 1024 cyl limit.

So you would have /boot the FIRST partition on the
disk then / and swap wherever

lilo or grub would be installed in /boot.

Then the bios when as designed go to the first primary
partition on the first HD looking to boot. Once the
boot starts Linucx doesn't care about the bios
limitations.

The maxtor software uses the same thing, I've never
used the Maxtor utility but I have used a WD utility
which is actually used DR DOS boot partition to then
load a boot loader, I had SuSE 7.3 on a setup using
this a long time ago.

This problem and other partition issues used to be why
distros like SuSE 7.x etc used to give you the option
of installing lilo on a floppy, or even IN your
Win95/98 installation. Back with win95/NT era you had
503 MB 2gig 7.8 gig then 32 GIG for win 95, then with
win98 you had a 64gig limitation.

Recommendations:
Flash the bios if possible: Some manufacturers have
updats for large HD support. I have a Compaq Deskpro
that is a Pentium MMX 166 that has a 60 gig fully
recognized, that is my firewall computer/gateway Still
in service. (Quiet  passive cooling  No CPU Fan!!)

Buy an ATA card and disable the MB detection of the HD


It might be possible to use the partition made by the
maxtor utility as /boot  Not sure as I never have used
this. 

You could also put lilo or grub on a first/primary
partition in the first 1024 cylinders by custom
partitioning the drive.

Hope some of this makes sense to you.

Bryann



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