BIOS sees 6GB; Linux sees 250GB

[Smitty]

I know this question comes up time and time again... but I just want to
make sure what I am seeing is true. I have an old Aptiva Pentium
200MMX computer. I want to run FreeNAS on it with a set of three 250GB
hard drives.

I downloaded the most current BIOS (dated 2003) from IBM for this
computer. But, still when I go into the BIOS, it detects the 250GB
hard drives as 6GB.

But, when I load FreeNAS (a mini-linux distro), it sees the hard drive
as 250GB.

So, am I correct to assume that if the OS can see the hard drive for
what it truly is, even though the BIOS can't... it will still function
correctly?

From what I read, both the motherboard and BIOS have to support a large

hard drive. And, I can't find any documentation that leads me to
believe this will or will not work. I'd like to save a few bucks and
not have to buy a controller card... and so far it looks like I can get
away with it.

I just don't want to wake up one day and when I try to copy some data
off of the hard drive, it gives me garbage, because it really wasn't
storing it correctly all along.

-rs

 

[Rod Speed]

I know this question comes up time and time again...
but I just want to make sure what I am seeing is true.
I have an old Aptiva Pentium 200MMX computer. I want
to run FreeNAS on it with a set of three 250GB hard drives.

I downloaded the most current BIOS (dated 2003)
from IBM for this computer. But, still when I go into
the BIOS, it detects the 250GB hard drives as 6GB.

Its important to ensure that you have a drive type of AUTO
in the bios and that you wipe the drive with something like
clearhdd too. If you dont use an AUTO drive type setting,
the bios may well just be using the CHS values you've got in the
drive type entry and set the drive to the 6G they correspond to.

Ditto with the geometry detail in the MBR, that can see the
bios decide that its only a 6G drive if its been setup that way
in the past. Thats the reason for wiping the drive with clearhdd.

But, when I load FreeNAS (a mini-linux distro),
it sees the hard drive as 250GB.

So, am I correct to assume that if the OS can see the hard drive for
what it truly is, even though the BIOS can't... it will still function
correctly?

Likely it will. Dunno about FreeNAS specifically tho.

From what I read, both the motherboard
and BIOS have to support a large hard drive.

Nope, the bios only matter when booting.

Its perfectly possible to boot what the bios decides is a 6G drive
and have the OS work it out for itself and handle that properly.

And, I can't find any documentation that leads me to believe this will
or will not work. I'd like to save a few bucks and not have to buy a
controller card... and so far it looks like I can get away with it.

Yeah, I'd be surprised if it wouldnt work fine.

I just don't want to wake up one day and when I try to
copy some data off of the hard drive, it gives me garbage,
because it really wasn't storing it correctly all along.

Shouldnt be hard to test that by filling the drive with
known files and getting them back and comparing them.
Just make up some big zip files and let zip work out
if they have got corrupted etc.

 

[Anton Ertl]

So, am I correct to assume that if the OS can see the hard drive for
what it truly is, even though the BIOS can't... it will still function
correctly?

I would guess so. However, if you want to boot from the drive, you
probably should put the boot partition in the first 6GB.

hard drive.

Linux drivers don't use the BIOS, so as soon as Linux runs, it does
not matter whether the BIOS supports the drive or not. As for the
motherboard, AFAIK the only problems with large drives come from the
BIOS.

I just don't want to wake up one day and when I try to copy some data
off of the hard drive, it gives me garbage, because it really wasn't
storing it correctly all along.

If you want to make absolutely sure, you can fill the disk under Linux
with stuff that you can check, and then check it.

- anton

 

[Arno Wagner]

I know this question comes up time and time again... but I just want to
make sure what I am seeing is true. I have an old Aptiva Pentium
200MMX computer. I want to run FreeNAS on it with a set of three 250GB
hard drives.

I downloaded the most current BIOS (dated 2003) from IBM for this
computer. But, still when I go into the BIOS, it detects the 250GB
hard drives as 6GB.

But, when I load FreeNAS (a mini-linux distro), it sees the hard drive
as 250GB.

So, am I correct to assume that if the OS can see the hard drive for
what it truly is, even though the BIOS can't... it will still function
correctly?

Usually the BIOS should see the first 6GB. If that is the case,
you can boot from it by placing the kernels and bootloader
there. I usually use a small (100MB) partition at the beginning of
the disk for this purpose. After Linux is loaded, the BIOS does not
matter anymore.

hard drive.

The motherboard is only relevant insofar as the BIOS is tied to it.
The BIOS is relevant for any older OS and for seeing the HDD
in the first place (if it does not, you cannot boot) and seeing
enough of it in a way the boot-code and kernel can be loaded. After
thet it becoimes irrelevant. The problem is that in many cases a too
big HDD is not seen at all. For Linux you have to resort to floppy or
CD-boot in that case.

And, I can't find any documentation that leads me to
believe this will or will not work. I'd like to save a few bucks and
not have to buy a controller card... and so far it looks like I can get
away with it.

I just don't want to wake up one day and when I try to copy some data
off of the hard drive, it gives me garbage, because it really wasn't
storing it correctly all along.

Should not happen with Linux. With Windows, you still have
issues with too large HDDs as well, unless you have the
newest service. If Limux puts a Filesystem on it, it should
reliably read and write it. Of course there is a small
risk that one day you BIOS decides it does not like
your HDD anymore. But then you can move the disk to
another compyter ans still get the data back.

Arno

 

[Folkert Rienstra]

I would guess so. However, if you want to boot from the drive, you
probably should put the boot partition in the first 6GB.

For Windows, since some Windows utilities for drive management
still use BIOS. Find the right alternatives and it doesn't matter.

Linux drivers don't use the BIOS,

Neither does Windows.

so as soon as Linux runs, it does not matter whether the BIOS supports

the drive or not. As for the motherboard, AFAIK the only problems with
large drives come from the BIOS.

 

[Folkert Rienstra]

Usually the BIOS should see the first 6GB. If that is the case,
you can boot from it by placing the kernels and bootloader
there. I usually use a small (100MB) partition at the beginning of
the disk for this purpose. After Linux is loaded, the BIOS does not
matter anymore.


The motherboard is only relevant insofar as the BIOS is tied to it.
The BIOS is relevant for any older OS and for seeing the HDD
in the first place (if it does not, you cannot boot) and seeing
enough of it in a way the boot-code and kernel can be loaded. After
thet it becoimes irrelevant. The problem is that in many cases a too
big HDD is not seen at all. For Linux you have to resort to floppy or
CD-boot in that case.



Should not happen with Linux. With Windows, you still have
issues with too large HDDs as well, unless you have the
newest service. If Limux puts a Filesystem on it, it should
reliably read and write it.

Of course there is a small risk that one day you BIOS decides it does
not like your HDD anymore.

If the bios decides to not like it anymore, the drive is dead, babblemouth.

But then you can move the disk to another compyter ans still get the data back.

Utterly clueless, as always.