Hardware Reference
In-Depth Information
BIOS Limitations
Many older (pre-1998) BIOSs can't handle drives above the 8.4GB limit, and other BIOSs (pre-
2002) have other limits, such as 137GB. Some drives ship with a setup or installation disc containing
a software BIOS substitute, such as Ontrack's Disk Manager, Phoenix Technologies' EZ-Drive
(Phoenix purchased EZ-Drive creator StorageSoft in January 2002), and their OEM offshoots (Drive
Guide, MAXBlast, Data Lifeguard, and others). However, I don't recommend using these because
they can cause problems if you need to boot from floppy or CD media or if you need to repair the
nonstandard MBR these products use.
Internal ATA drives larger than 137GB require 48-bit LBA support. This support
must
be provided
in the OS; it can also be provided in the BIOS, or both. It is best if both the OS and the BIOS support
it, but it can be made to work if only the OS has the support.
One of the following is required for 48-bit LBA support in the OS:
• Windows 8/7/Vista.
• Windows XP with Service Pack 1 (SP1) or later.
• Windows 2000 with Service Pack 4 (SP4) or later.
• Windows 98/98SE/Me or NT 4.0 with the Intel Application Accelerator (IAA) loaded. This
solution works only if your motherboard has an IAA-supported chipset. See
http://downloadcenter.intel.com
and search for IAA for more information.
And either of the following is required for 48-bit LBA support in the BIOS:
• A motherboard BIOS with 48-bit LBA support (usually dated September 2002 or later)
• An adapter card with onboard BIOS that includes 48-bit LBA support
If you have both OS and BIOS support for 48-bit LBA, you can simply install and use the drive like
any other internal drive. On the other hand, if you do not have 48-bit LBA support in the BIOS, but
you do have it in the OS, portions of the drive past 137GB are not recognized or accessible until the
OS is loaded. This means that if you are installing the OS to a blank hard drive and booting from an
original XP (pre-SP1) CD or earlier, you need to partition up to the first 137GB of the drive at
installation time. After the OS is fully installed and the service packs added, the remainder of the
drive beyond 137GB is recognized. At that point, you can then either partition the remainder of the
drive beyond 137GB using the XP Disk Management tools or use a third-party partitioning program
such as Parted Magic (
www.partedmagic.com
)
to resize the first partition to use the full drive.
If you are booting from an XP SP1 or later CD (meaning a CD with Service Pack 1 already applied),
you can recognize and access the entire drive during the OS installation and partition the entire drive
as a single partition greater than 137GB if you like.
Booting from 2.2TB or larger drives requires a newer type of BIOS called UEFI (Unified Extensible
Firmware Interface), which supports booting from a new type of partition format called GUID
(globally unique identifier) Partition Table (GPT). This is because the traditional MBR disk format
only supports drives up to 2.199TB, and legacy (non-UEFI) BIOS can only boot from MBR-formatted
drives.
If you need more or faster SATA interface connections, you can use add-on cards from companies
such as Promise Technology (
www.promise.com
)
. These cards support drives up to and beyond the
137GB limit imposed by the ATA-5 and older standards.
Note that external USB and FireWire drives don't have these capacity issues because they don't rely
