Why is the full capacity of EIDE drives larger than 137GB (128GB binary) not recognized in Windows 2000/XP?

48-bit LBA support is necessary for drives larger than 137GB
(128GB binary). The following conditions are necessary for the
correct functioning of 48-bit LBA support in Windows 2000/XP:

Windows XP Service Pack 1 (SP1) must be installed for Windows XP
versions prior to August 2002. For information about SP1, see
Microsoft Article 322389.

http://support.microsoft.com/default.aspx?scid=kb;en-us;322389


The system must have a 48-bit LBA-compatible Basic Input/Output
System (BIOS) installed. This includes EIDE controller card BIOSs.


You must enable the support in the Windows registry.

The Microsoft Knowledge Base articles listed below provide important
information about 48-bit LBA support for drives larger than 137GB
in Windows. For full details, carefully review the relevant article.

48-bit LBA Support for ATAPI Disk Drives in Windows 2000.
(Microsoft Article ID : 305098)

http://support.microsoft.com/default.aspx?scid=kb;en-us;305098

How to Enable 48-bit Logical Block Addressing Support for ATAPI Disk
Drives in Windows XP.
(Microsoft Article ID : 303013)

http://support.microsoft.com/default.aspx?scid=kb;en-us;303013