Hardware Reference
In-Depth Information
Although the BIOS services use 64-bit LBA (allowing up to 2
64
sectors) for even greater
capacity,the144petabyteATA-6limitationisthelowestcommondenominatorthatwould
apply. Still, that should hold us for some time to come.
Because hard disk drives have been doubling in capacity every 1.5 to 2 years (a corollary
ofMoore'sLaw),Iestimatethatitwilltakeusuntilsometimebetweentheyears2031and
2041beforewereachthe144PBbarrier(assumingharddisktechnologyhasn'tbeencom-
pletely replaced by then). Similarly, I estimate that the 9.44ZB EDD BIOS barrier won't
be reached until between the years 2055 and 2073! Phoenix originally claimed that the
EDD specification would hold us until 2020, but it seems they were being quite conser-
vative.
The 137GB barrier proved a bit more complicated than previous barriers because, in ad-
dition to BIOS issues, operating system issues also had to be considered.
Internal ATA drives larger than 137GB require 48-bit LBA (logical block address) sup-
port. This support absolutely needs to be provided in the OS, but it can also be provided
in the BIOS. It is best if both the OS and BIOS provide this support, but it can be made to
work if only the OS has the support.
Having 48-bit LBA support in the OS requires one of the following:
• Windows XP with Service Pack 1 (SP1) or later.
• Windows 2000 with Service Pack 4 (SP4) or later.
•Windows98/98SE/MeorNT4.0withtheIntelApplicationAccelerator(IAA)loaded.
This solution works only if your motherboard has an IAA-supported chipset. See
ht-
tp://downloadcenter.intel.com
and search for IAA.
Having 48-bit LBA support in the BIOS requires either of the following:
• A motherboard BIOS with 48-bit LBA support (most of those dated September 2002
or later)
• An ATA host adapter card with onboard BIOS that includes 48-bit LBA support
If your motherboard BIOS does not have the support and an update is not available from
your motherboard manufacturer, you may be able to use a card. Promise Technology
(
www.promise.com
)
makes several PCI cards with either PATA or SATA interfaces as
well as an onboard BIOS that adds 48-bit LBA support.
Note that if you have both BIOS and OS support, you can simply install and use the drive
like any other. If you have no BIOS support, but you do have OS support, portions of
the drive past 137GB are not recognized or accessible until the OS is loaded. 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 and install up to the first 137GB of the drive at install-
