250GB with 04/08/2002-SiS-620-P6SEP-MEC-00 possible?

BIOS update, EIDE card, or overlay software? (FAQ Hard disk recognition)
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Rolf
BIOS Newbie
Posts: 18
Joined: Mon Feb 16, 2004 5:48 pm
Location: Leipzig, Germany

Hi,

I run a Via Cyrix 600MHz CPU on a P6SEP-ME mobo as a 24/7 server. Here is the data I got from the boot screen.

Award Modular Bios 4.51PG
P6SEP-ME Ver 3.7b 04/08/2002
04/08/2002-SiS-620-P6SEP-MEC-00

I was wondering if the board can handle a 250GB HD. Is the 128GB limit a BIOS or a hardware issue after all?

I run Linux so up to now I never bothered with BIOS limitations in this respect since Linux can deal with the "usual" 8G and 32G barriers just fine. Lately, I put a 200G HD into a Mobo which I believe is "P6LX-A+ Ver 2.1 12/29/1997" and it recognized only 128G (or 137G according to fdisk). The computer is 500 km away, so I had to resort to some hackery to read the BIOS string. That is what made me pause before I go and buy the new HD for my other server.

Oh, by the way, I do not need either of the big disks to boot. They are pure data and backup storage disks.

Regards

Rolf
cp
BIOS Guru
Posts: 1914
Joined: Mon Oct 21, 2002 9:07 pm
Location: Germany

no problem for linux. and if you don't even need to boot from those disks, you are all safe. just connect them and boot as usual. don't even bother detecting them in the bios. everything will work without telling the bios. of course you CAN insert them in the bios (if the detection routine hangs just jumper the drives for 32GB clipped). as soon as you boot the kernel (and thus linux) you will be surprised to see the ide detection getting all the correct data from the drives itself. just make sure your kernel is up to date because it needs to support 48bit LBA.
kernels since 2.4.19 support 48bit LBA but 2.6.x will be fine anyways.


for the other mainboard: what kind of os are you running on that one? the size limit is (will be?) always a matter of software. first of all (this is why this site exists) some award bios have a serious bug which crashes them when detecting drives larger than 32GB. beside this problem there are software issues when it comes to the operating system (there are MANY different issues). anyways...to cut it short: modern os (Windows XP SP1 + RegPatch or SP2, Windows 2000 SP4 and later or Linux kernel 2.4.19 and later) don't rely on the information of the bios but rather query the hardware themselves thus working around the bios (bugs). all the modern operating system use 48bit LBA which enables them detecting and using the full potential of hdds upto ~144 PetaByte (thats 144.000.000GB).
Rolf
BIOS Newbie
Posts: 18
Joined: Mon Feb 16, 2004 5:48 pm
Location: Leipzig, Germany

cp wrote:no problem for linux. and if you don't even need to boot from those disks, you are all safe.
Cool! I was just a little bit afraid because of the experience with the other computer. But...
cp wrote:kernels since 2.4.19 support 48bit LBA but 2.6.x will be fine anyways.
... the other machine is running Debian stable. And that means kernel 2.4.18 which I guess is the reason for it not accessing the whole disk.

Thanks, cp. You helped me a great deal.
cp
BIOS Guru
Posts: 1914
Joined: Mon Oct 21, 2002 9:07 pm
Location: Germany

debain has precompiled 2.6.8.2-i386 kernel packages, too. just apt-get them :) or build your own kernel which is way cooler though.
Rolf
BIOS Newbie
Posts: 18
Joined: Mon Feb 16, 2004 5:48 pm
Location: Leipzig, Germany

cp wrote:debain has precompiled 2.6.8.2-i386 kernel packages, too. just apt-get them :) or build your own kernel which is way cooler though.
yes, you are right. I forgot that I already had a custom kernel. And that I should not replace it because I need a custom compiled module for the AVM Fritz card. Have not touched that box in ages. But the 200G drive is not used at all at the moment, so having only 60% of the capacity is not any kind of problem there.

Thanks again for your insightful comments, cp.
cp
BIOS Guru
Posts: 1914
Joined: Mon Oct 21, 2002 9:07 pm
Location: Germany

you're welcome :)
Rolf
BIOS Newbie
Posts: 18
Joined: Mon Feb 16, 2004 5:48 pm
Location: Leipzig, Germany

OK, so I bought the 250G drive. The board recognizes 136G of it and does not hang. Linux is indeed capable to access the full 250G with a 2.6.12 kernel.

Then I got curious and put the drive into a machine running off a very old Pentium 1 motherboard. There I only had 136G and /var/log/messages showed that LBA48 addressing was not possible and therefore capacity clipped. This was on a 2.4.26 kernel, so I do not know exactly why it did not work.
cp
BIOS Guru
Posts: 1914
Joined: Mon Oct 21, 2002 9:07 pm
Location: Germany

this _may_ depend on the chipset itself or the missing chipset specific drivers in the kernel (exotic chipset, very old, flaky). make sure the kernel you are using on the machine has the chipset's ide driver build in. i suppose the generic ide driver will _not_ work!

anything else needs further investigation as i found the following:

"/* Don't use LBA48 on ALi devices before rev 0xC5 */" (in v2.4.20-pre2-ac3)

so it seems that some chipsets do not support LBA48 because of hardware flaws. anyone remembering those RZ1000 IDE chipsets? though they did support read-ahead they went boom when read-ahead was enabled..nice 'feature' ;)

EDIT:
"Don't use LBA48 mode on ALi <= 0xC4" (from the v2.6.17 alim15x3.c). So ALi southbridges with revisions before 0xC5 will not support LBA48 as a result of a faulty hardware implementation (i suppose).
Rolf
BIOS Newbie
Posts: 18
Joined: Mon Feb 16, 2004 5:48 pm
Location: Leipzig, Germany

cp wrote:this _may_ depend on the chipset itself

[...]

"Don't use LBA48 mode on ALi <= 0xC4" (from the v2.6.17 alim15x3.c).
I am not sure if the other computers southbridge is ALi or not. Just for the heck of it I loaded Knoppix 4.0.2 from the old computer and the full 250G were recognized. So at least in this case it appears that newer kernels would have solved the issue on the older computer as well. Said Live-CD has kernel 2.6.12.
cp
BIOS Guru
Posts: 1914
Joined: Mon Oct 21, 2002 9:07 pm
Location: Germany

one to solve them all ;)

so, just to repeat it once again: there is (almost, some old ali chipsets seem to be buggy) no restriction in hdd size for any system even with the onboard components if you choose an os which is capable of unleashing the real power of the hardware ;)

i once did some tests with a 80GB hdd on an iNTEL 430FX board (with an iNTEL Pentium 133) just to measure the throughput on the ide channel. ~11MB/s is the limit of the chipset with PIO4 MWDMA2 (as stated in the datasheets) and with the 80GB hdd it really peaked out at that speed. i must say i was really impressed.
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