Using 32-Bit Disk Access on WD 2540 Hard Disk Drives

• Microsoft Windows operating system versions 3.1, 3.11
• Microsoft Windows for Workgroups versions 3.1, 3.11

The following article contains information about the use of Windows and Windows for Workgroups with third-party products or configurations that have not been tested and are not supported by Microsoft.

If the steps or procedures described in this article do not function properly, contact the manufacturer of the third-party product for more information or use a supported configuration.

SYMPTOMS

After you enable 32-bit disk access (FastDisk), the system becomes unstable or stops responding (hangs) during startup, or Windows displays one of the following error messages:

• The Microsoft Windows 32-bit disk driver (WDCTRL) validation failed at phase XX, XX.
• Windows: This application has tried to access your hard disk in a way that is incompatible with the Windows 32-bit disk access feature (WDCTRL). This may cause your system to become unstable.
• Insufficient memory or address space to run Windows in Enhanced mode. Remove TSR programs to free memory.

CAUSE

These errors occur when you use a hard disk with more than 1024 cylinders. IDE hard disks must have CMOS settings with the following upper limits to use 32-bit disk access:

   Cylinders:      1024
   Heads:          16
   Sectors/Track:  63
   Bytes/Sector:   512

If your hard disk is incompatible with 32-bit disk access, you can disable this feature by following these steps:

1. In Control Panel, double-click the 386 Enhanced icon.

2. Choose the Virtual Memory button, then choose Change.

3. Clear the Use 32-Bit Disk Access check box.

RESOLUTION

The following list of workarounds is grouped by manufacturer. If your hard disk does not appear in this list, please contact your hard disk manufacturer for more information.

Conner

7546AT:

The 7546AT Conner drive is a 540 megabyte (MB) drive with 1048 cylinders, 16 heads, and 63 sectors per track. Reducing the number of cylinders in the CMOS settings to 1024, then repartitioning and reformatting the disk may allow 32-bit disk access and 32-bit file access to work.

WARNING: Be sure to back up your data before you repartition or reformat your hard disk. Repartitioning or reformatting the disk will remove all information from the disk.

IBM

If you have an IBM ValuePoint computer that supports IDE hard disks with more than 1024 cylinders, you should download two files from the IBM BBS. The files are VPWINBHF.DSK and LDF.COM. For information about how to enable 32-bit disk access using these files, please contact IBM.

Maxtor

7540AV:

To use 32-bit disk access with the Maxtor 7540AV hard disk, you may need to reduce the cylinder count from 1048 to 1024.

7546AT:

To use 32-bit disk access with the Maxtor 7546AT hard disk, you may need to reduce the cylinder count from 1048 to 1024.

7548AT:

The Maxtor 7548AT IDE hard disk drive has 1060 cylinders, 16 heads, and 63 sectors per track. Reducing the cylinder count in the CMOS settings to 1024 allows 32-bit disk access to work. If you continue to get an error message, you may need to add the NOMOVEXBDA parameter to the EMM386.EXE command in the CONFIG.SYS file.

For more information about Maxtor hard disks and 32-bit disk access compatibility, please contact Maxtor.

Quantum

LPS-540AT:

The Quantum LPS-540AT hard disk defaults to 1120 cylinders, 59 logical sectors per track, and 16 heads. According to Quantum technical support, this drive can be configured with 1024 cylinders, 63 logical sectors per track, and 16 heads to make this drive compatible with 32-bit disk access.

NOTE: Quantum's BBS has a self-extracting file, IDE_DOS.EXE, that contains an MS-DOS utility that allows the drive to be formatted to 540 megabytes. Included in this file is IDE_WIN.386, which is the Quantum replacement for WDCTRL.

For more information about configuring your Quantum hard disk or about using the files listed above, please contact Quantum.

Samsung SHD-30560A

Samsung recommends 1024 cylinders, 16 heads, and 63 sectors (for a total of 528.0 MB) to use 32-bit disk access.

Western Digital

WDAC-2420:

The Western Digital 2420 hard disk is incompatible with 32-bit disk and file access in Windows. For information about using this hard disk with 32-bit disk and file access in Windows, please contact Western Digital.

Caviar WDAC-2540:

Western Digital has confirmed that the Caviar model 2540 516 MB hard disk uses BIOS parameter settings that are incompatible with the 32-bit disk access driver (WDCTRL) included with Windows.

To work around this problem, use one of the following methods:

• If the BIOS in your computer does not support drives with more than 1024 cylinders, download a utility program called WDSWT.COM from the Western Digital BBS. This utility stamps the disk with a parameter translation brand so that it reports 1024 cylinders to the Windows 32-bit disk access driver. This procedure is reversible should the need arise.

  NOTE: WDSWT.COM is for use with the AC2540 drive only. It is not intended for use on the AC2700 (730 MB) or AC31000 (1083 MB) drives.

• Download the self-extracting file WIN31.EXE from the Western Digital BBS. This file contains the driver WDCDRV.386, which can be used to replace WDCTRL.
• Update your computer's ROM BIOS to a version that supports logical block addressing (LBA) to automatically translate more than 1024 cylinders.
• Disable 32-bit disk access.
• Change the CMOS settings for the drive to 1024 cylinders or fewer, and then run FDISK and reformat the disk. This workaround allows the use of WDCTRL, but results in a loss of 11.8 MB of disk space.

  WARNING: Be sure to back up your data before you repartition or reformat your hard disk. Repartitioning or reformatting the disk will remove all information from the disk.

MORE INFORMATION

32-bit disk access is a set of protected-mode device drivers that work together to enhance your computer's BIOS. It filters interrupt (INT) 13H calls to the hard disk controller and directs them in the most efficient way for the system (either through the 32-bit interface with the hard disk controller or through the system BIOS).

In Windows for Workgroups version 3.11, a hard disk that is incompatible with 32-bit disk access may still be able to use 32-bit file access. The largest performance gain is accomplished using 32-bit file access. Using 32- bit file access provides compatibility with future versions of Windows.

The Windows 32-bit disk access driver (WDCTRL) supports disk controllers that are compatible with the Western Digital 1003 controller interface standard, but is compatible only with hard disks with 1024 or fewer cylinders.

REFERENCES

For more information about 32-bit disk access, see the Microsoft Windows for Workgroups "Resource Kit," version 3.11, pages 1-19.