BIOS sees 6GB; Linux sees 250GB
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From: Smitty on 23 Jan 2006 00:41 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
From: Rod Speed on 23 Jan 2006 01:33 Smitty <r_o_b_s_m_i_t_h(a)yahoo.com> wrote > 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.
From: Anton Ertl on 23 Jan 2006 04:55 "Smitty" <r_o_b_s_m_i_t_h(a)yahoo.com> writes: >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. >>From what I read, both the motherboard and BIOS have to support a large >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 -- M. Anton Ertl Some things have to be seen to be believed anton(a)mips.complang.tuwien.ac.at Most things have to be believed to be seen http://www.complang.tuwien.ac.at/anton/home.html
From: Arno Wagner on 23 Jan 2006 08:29 Previously Smitty <r_o_b_s_m_i_t_h(a)yahoo.com> wrote: > 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. >>From what I read, both the motherboard and BIOS have to support a large > 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
From: Folkert Rienstra on 23 Jan 2006 09:35
"Anton Ertl" <anton(a)mips.complang.tuwien.ac.at> wrote in message news:2006Jan23.105503(a)mips.complang.tuwien.ac.at > "Smitty" <r_o_b_s_m_i_t_h(a)yahoo.com> writes: > > 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. > > > > From what I read, both the motherboard and BIOS have to support a > > > large hard drive. 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. > > > 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 |