Hard disk size limit ASUS A7N8X-VM

Thanks for the knowledgeable research, Gary, that is more than I could get out of the ASUS site.  I suspect it has 48 bit LBA.  The reason I ask this question is that I have had a 250GB drive fdisked and partitioned working perfectly fine on the board for a long time.  It is a dual boot 98Se and XP, has to stay that way.

I just replaced it with a 320GB drive -- fdisk is now seizing (i.e. freezing 98SE cold), and when I wrote data to the drive, it scrambled the windows folder completely.  Since this is not a data problem (a data clone), I am trying to decide if the drive is just plain defective, or if the MB BIOS has some 256GB limit.   Argh!

I would run the vendor and other diagnostics on the drive and mobo.

UBCD is free and has plenty of tools for this.

UBCD Free vendor and other diagnostics and utilities
www.ultimatebootcd.com

I hope this helps !

You can trivially confirm that the BIOS supports 48-bit addressing ... just look in the BIOS and see what size it shows for the drive :-)

But the issue you're encountering is almost certainly due to using FDisk --> even the updated FDisk/Format utilities do NOT support 48-bit addressing [They simply resolved the 64GB reporting issue in the original Windows 98 FDisk/Format utilities]

If your 250GB disk was working okay, you most likely didn't format it beyond the 28-bit LBA limit with FDisk, but used XP's disk management instead.   The same thing would work fine with a 320GB disk (or even larger) ... but NOT with FDisk.

The best thing to do is to use a 48-bit compliant partitioning/formatting utility.   But even then you have to add 48-bit support to Windows 98 (which does not natively support 48-bit addressing) OR restrict the '98 partition to the part of the drive accessible with 28-bit addressing (the first 128GB/137GB).   With Intel controllers you can do this with Intel's Application Accelerator; but there's a universal patch available (for $10) here:  http://www.geocities.com/rloew/Programs/Patch137.htm  [Note:  I do not use this patch; all of my multi-boot systems that have '98 on them have the '98 partition within the first 128GB of the drive -- this works fine even on a 750GB drive.  Note also that the "demo" version of the patch limits drive access to the first 145GB ... just enough to prove it works!!   I think that's a TERRIBLE condition -- you could still corrupt the drive if you didn't notice that restriction.  Bottom line:  Spend the $10 to try the patch if you want to add 48-bit LBA support]
   
Also note that this patch will let '98 fully access the drive ... but does NOT modify the FDisk/Format/Scandisk utilities -- which will still fail ... so you need to be sure you don't use them (the key caveat here is to be sure and patch '98 to not automatically run Scandisk after an improper shutdown).

Bottom line:  On your related issue (not what you asked here), the problem is FDisk -- NOT the drive or the BIOS.

... Note there is also a free 48-bit driver available on the MSFN forums (free registration required) ... but it apparently hasn't been updated in ~ 2 years and it's not clear just how universal it is.   I'd spend the $10 noted above :-)

Hi Gary --

I partitioned the other drive with FDISK as well, so it is not an XP vs. Fdisk partitioning issue.  Fdisk has always worked fine up to 250GB, no matter how I partition the drive.  I think you hit the key issue here --

"all of my multi-boot systems that have '98 on them have the '98 partition [starting] within the first 128GB of the drive -- this works fine even on a 750GB drive."

That is exactly what happened with the 250 drive -- all partitions started in the first 128 GB, except the last one, which I think I redid with NTFS, and later remade it back to FAT32.  I also did similarly with this 320 disk, using the XP partitioning, but only AFTER doing the fdisk formatting.  It did not fix the problem.

I notice now that there is some relict partitioning corruption which I can't get rid of -- and SysExpert -- this is AFTER applying the "clean master boot record" and "clean disk" utilities provided by Hitachi !!

Sorry, I don't trust any add ons like the $10 one you mentioned.  My data is too crucial to entrust to crippler ware.  I found a small utility called "FAT32FORMATTER" .   It might do the trick for formatting partitions beyond the 128MB start.  But once I had the top partition on the 250Gb drive as FAT32, 98SE could read it fine, even though its sectors were well beyond the 128GB position.   I don't get it ?

We may have diverged, but I think you finally hit the key to this problem -- if 98Se relies on the BIOS but XP and others don't then THAT is the root of the potential corruption -- which is what I was really getting at in the original question.  It boils down to a built in debacle that is waiting to hit -- depending on MB type, BIOS features, HDD size, and of course the unending built-in limitations of M$ software.  Like a demon in the night, this conglomeration of "gotchas" is just waiting to strike at the least expected time.

Thanks VERY much for your insights into this problem.  As a final note, all partitions I do are less than 128GB, so the issue is in all the other features discussed.  I've never exceeded 128 on FAT32.  Cheers.

I didn't mind the divergence -- always glad to help.   You're absolutely right that you can get "bit" by the differences in disk access.   You need to be sure you know whether or not the BIOS supports 48-bit LBA;  be sure you've made the appropriate updates for Windows 2000 [SP4 plus "EnableBigLBA"] BEFORE you try to access a drive larger than 128GB;  etc.   And if you multi-boot (I frequently do); you need to be sure you understand how each OS is managing the disk accesses.   For example, even on a system that does not support 48-bit addressing in the BIOS, XP can still use a large drive just fine (as long as the controller supports it).   But if you're doing that, you need to be sure that you do NOT use any 3rd party tools that access the drive through the BIOS.

... it can definitely get interesting :-)   [As you noted, a "... demon in the night ... waiting to strike ..." !!]

Gary --

If you are still there, would 2000 be a sensible replacement for 98 then?  The whole point of this dual boot OS is simply to backup the XP installation.  I know 2000 will work on FAT32, and sit more or less OK with XP on the same drive, but does it have the same large disk addressing problems?  Maybe expand on that a bit?

2000 has full support for 48-bit logical block addressing, so if you simply want a different OS then that may be a good alternative.

A couple of notes, however:   If you install 2000, do it initially in a partition within the lower 128GB of the drive.  Then apply SP4 to the install.   And then add the "EnableBigLBA" key to the registry ... the easiest way to do that is just download this little utility, which will check for the necessary key, add it if needed, and be sure it has the right value:  http://www.48bitlba.com/download/enablebiglba/EnableBigLba.exe

If you don't want to run a dedicated utility, all you have to do is navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\atapi\Parameters
and add a DWord named EnableBigLBA with a value of 1

... then reboot => and 2000 will then have full 48-bit LBA capability.

sounds like the answer to this problem.  I will give it a try and let you know what happened -- next year.  Thanks again, and MC and HNY.