137 GB Limitation

The Serial ATA BIOS is not subject to the same limitations as the Parallel ATA BIOS. However the 137 GB limitation imposed by most operating systems still applies.

Windows Vista
Windows Vista natively supports 48 bit LBA and will not require any update. If you encounter the 137 GB limitation in your Windows Vista installation, there are three possibilities:

1. The drivers for your Serial ATA controller are not loaded correctly. Please check with the controller manufacturer for updated drivers and load them according to their instructions.

2. The hard drive itself has been clipped to a lower capacity. Please use Seatools for DOS to reset the capacity.

   • See here for a full tutorial on the use of Seatools for DOS.
   • See here for instructions on this specific operation (though the article refers to ATA drives, it is relevant for Serial ATA drives as well).

3. If the drive is connected inside a third-party external enclosure, the enclosure could be limiting the drive's usable capacity. Either install the drive internally, inside a computer, or contact the enclosure manufacturer for more information.

Windows XP/2000
Please refer to the following Microsoft Knowledge Base articles for assistance with the Windows Service Packs and enabling 48 bit LBA support.

• Windows XP
• Windows 2000

Windows 98 and Me do not provide support for 48 bit LBA. There are no Service Packs or patches available from Microsoft to enable this support.

Mac OS X natively supports 48 bit LBA. This allows the drive to be recognized with the full capacity available at installation.

Note: Serial ATA host controllers that identify themselves to the system as emulated SCSI devices and will not be subject to the 48 bit LBA limitations imposed on Parallel ATA drives.

Many of the newer onboard Serial ATA chipsets use Parallel ATA emulation. If the Serial ATA controller drivers are not loaded during the operating system installation, the Serial ATA drive will only show the capacity supported natively by the operating system version being installed.