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Enable48BitLBA | Break the 137Gb barrier!

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hi all~ :hello:

my biggest question is that,how to see that the new driver file is working successfully?

and to setup it,just copy the file to the direction "iosubsys" in the real dos mode?

thanks all~

That's pretty much it.

Copy the updated ESDI_506.PDR to x:\WINDOWS\SYSTEM\IOSUBSYS (x:\WINDOWS is your Windows boot folder, normally C:\WINDOWS).

I don't think the file is locked by Windows, so you can probably copy it in Windows and restart.

Although, as with any file replacement, take a copy of the old one just-in-case!

:o Something to be aware of...

I found out that even though I copied the updated file into IOSUBSYS, Windows was actually loading an older version at run time from C:\WINDOWS\OPTIONS\CABS!!!

I found many drivers that were loading this way. Even some 98SE2ME updated files were actually loading old 98SE official Microsoft files from OPTIONS\CABS instead...

I copied all the newer files over the old ones in OPTIONS\CABS.

I searched the registry and could not find or understand WHY Windows would load some files from OPTIONS\CABS and some from WINDOWS\SYSTEM and sub-folders...

To check, go to Device Manager, Properties on the device - for example Primary IDE Controller, Driver, Driver File Details.

Then look at the path for each file.

If any are loading from a different location, then either update that file, or delete it (with caution!).

I would suggest checking all devices in Device Manager since I found a scattering of wrongly loaded drivers.

EDIT: Weird! I have found some files that are loaded from two different places by two different drivers???

Does this mean that there are two images of the file in memory? - Resource wastage!

Edited by RetroOS

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hi all~ :hello:

my biggest question is that,how to see that the new driver file is working successfully?

and to setup it,just copy the file to the direction "iosubsys" in the real dos mode?

thanks all~

The important part of that was "in real dos mode". The reason we suggest that you switch the file before Windows starts is that otherwise it is possible for file corruption to occur on the drive because Windows will be seeing the wrong size of drive and possibly write over important files. Therefore do NOT do the change of file from within Windows.

It appears from the subsequent post that there are other reasons, but this is the primary reason - in DOS, the file system will remain intact and safe, whereas in Windows, until you change that file, your file system is in danger of corruption. Just stop Windows loading and go into the DOS prompt to do the switch.

If you want to ensure that Windows installs with the new file, see earlier posts regarding inserting the replacement file into the CAB files on your installation disk.

Hope that helps.

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I have a multi-boot configuration, with Win 98 SE and Win XP SP3.

Recently installed a new 160GB HDD, and discovered that some of my Word Documents were not being correctly read in the Win 98 partition.

After a bit of research I discovered this issue with the 128GB limit.

I have installed version 2222 of LLXX's patch, and it seems to have solved the problem; but I'm slightly worried that my data could still be corrupted at some point.

I'm not entirely clear whether the Win 98 issue is to do with the HDD total capacity; or the size of the partitions used? There seems to be conflicting information on this.

I've checked in Device Manager, and the system is correctly loading the new driver from the IOSUBSYS directory.

I can't run Scandisk on the new drive under Win 98, since it says there's not enough memory. Would it be a suitable test if I rebooted to DOS from the Win 98 partition, and ran scandisk under DOS?

Since my system had version 2222 rather than 2225, I obviously never downloaded the latest IDE drivers for Win 98 from Microsoft. I wondered if there's anything in that update that would improve performance on my HDD's; or would I be better off sticking with what I've got?

As I understand it there are two issues with HDD's over 128GB. Firstly the Win 98 problem; but also I need to check that my hardware is 48-bit LBA capable.

I have the following:

AS ROCK K7VT2 Version 2.00 mobo,

with American Megatrends BIOS version P1.20, Firmware Version 101.114, Date 12/10/2002.

plus these HDD's:

Western Digital 40GB, ATAPI-5, CHS: 4865, 255, 63 (System Drive with Win 98 and Win XP partitions)

Seagate 120GB, ATAPI-6, CHS: 19457, 255, 63 (48bit LBA capable)

Maxtor 160GB, ATAPI-7, CHS: 14593, 255, 63 (48bit LBA capable)

According to AS ROCK FAQ's all of their mobos are 48-bit LBA capable, but it's unclear whether this means all their current mobos; or all the mobos they've ever produced?

I would assume it's the latter, and the BIOS does seem to be correctly detecting the Maxtor's capacity.

However this doesn't guarantee that the hardware is 48-bit LBA capable, and I would ideally like to have a cast-iron guarantee that it is!

Edited by alexh110

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It seems to me that if WinXP is seeing all the appropriate hardware, then it is sufficiently LBA capable.

LLXX's patch is in daily use on at least three of my PCs, and I have lost no data since installation due to that matter. (I have lost some due to my own carelessness, but that is another matter entirely!)

The limit is per physical disk. One can only avoid it on a larger disk by creating a <137GB partition right at the start of the platter. The same size, but further onto the platter will suffer the data wraparound problem, with the FAT being overwritten by data. It was an error like that which caused me to find out about LLXX's patch, and it has never failed me.

Scandisk works OK for me, but all my partitions are smaller than 120GB. So maybe its limits are partition, not physical disk platter.

Once you have installed the LLXX patch (or R Loew's shareware patch) I'd suggest taking your 160GB drive (assuming it contains nothing irreplaceable at present), and filling it up with backup under Win98. Then re-attaching the drive under WinXP. Open a few files, and make sure that they are real and work properly.

Of course a valid backup is essential before starting on anything like this. But if your LLXX patch installation goes as smoothly as mine, you will never need the backup.

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And if you want more info or more answers, sit back, relax, and read this thread *and* all those linked from it.

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Thanks very much for the replies.

I've decided not to install BHDD31.ZIP, since this probably assumes that I have version 2225 of ESDI_506, instead of 2222. So I'm concerned it may screw up my system!

Can you give me any more information on the changes Microsoft made between versions 2222 and 2225?

I was hoping someone would have the same mobo as me, so they could confirm that it definitely does support HDD's above 137GB.

It says in the documentation that it supports UDMA Mode 6; but does this imply that it has 48-bit LBA support?

Since my Maxtor HDD is UDMA-7, I wonder whether this is backwards compatible with a UDMA-6 mobo?

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MS Ver 2225 fix 32gb Scandisk problem (click it for info)

UDMA-mode is not necessarily "directly" related to 48-bitLBA. It's the BIOS-aware ability to utilize 48-bitLBA (built into the HDD). Usually, backwards compatibility (UDMA-n) is also integral. The MS-fix (link above) is a "patch" for up-to 132gb as long as the BIOS supports it. The modules in the first post "patch" the MS "patch" to allow for 48-bitLBA, which exceeds the MS specification as long as the BIOS supports it.

HTH (am I correct, all?)

(p.s. I use this "patched" version as I have a 250gb-48bit HDD on a 48bit-aware PC)

edit - since it's a very new HDD, it probably is 48-bit; BIOS must support it...

edit2 - and the BHDD31 is a complete package... (re-read the link dencorso provided)

Edited by submix8c

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If any1 cares, I collected all 3 editions of Big HDD tools:


* Big Hard Disk Drive (BHDD) 3.1 tools for Windows 95/OSR1/OSR2/98/98 SP1/98 SE: Fixed FORMAT.COM (also installed by FDSKFRMT.EXE), Fixed FDISK.EXE (also installed by FDSKFRMT.EXE), Disk Defragmenter (DEFRAG.EXE 4.90.3000, also installed by SCANFRAG.EXE) + Disk Scanner [sCANDSKW.EXE 4.90.3000 (Windows mode) + SCANDISK.EXE (native DOS mode), also installed by SCANFRAG.EXE] + Improved Hard Disk Driver ESDI_506.PDR 4.10.2230 (Win98 SE only, also installed by ATADRV98.EXE):

- BHDD 3.1 [474 KB, English]:


- BHDD 3.1 [477 KB, French]:


- BHDD 3.0 [373 KB, Czech]:



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