On Wed, 18 Jul 2007 13:35:59 -0700, put finger to
keyboard and composed:

Yes, everything is up to date, BIOS, Drivers, and WinXP SP2 (Home and
Professional). I'm a stickler that way.

As I also noted before, my 200Gb and 240Gb work, but not the 400+
Gigabyte drives. Oddly, a hard drive information program I used
reported that the 200Gb and 240Gb drives didn't support 48bit data
transfer. I thought all hard drives over 137Gb required 48bit support?

If the BIOS is 48bit LBA compliant, then one possible reason for the
capacity limitation is that the drive has been configured to report
only that amount of sectors consistent with 28bit LBA. For example, I
believe some vendors (eg Compaq?) used to ship warranty replacement
20GB drives in place of 10GB drives, but crippled them to report only
10GB, ie the original capacity that the customer paid for.
Alternatively your drives may be jumpered to report a reduced capacity
for compatibility reasons.

What I would do is to query each drive at the lowest level using the
ATA Identify Drive command. This retrieves 256 words (512 bytes) of
information from the drive, including its "Maximum user LBA for 48-bit
addressing".

Here is a brief explanation:
http://tldp.org/HOWTO/Large-Disk-HOWTO-10.html

I use a very old Seagate utility called Find-ATA. It needs to run in
real DOS mode (not a Windows DOS box). I'd run it from a bootable,
write enabled DOS floppy diskette.

If your drive is configured as a primary slave, then the command to
use is ...

find-ata p s d

Find-ATA should then create a 512 byte file named drive1.ATA. You can
use the DOS Debug command to analyse this file (I believe Debug is
also available in a WinXP cmd window).

Type the following ...

debug drive1.ATA
-d 100 2ff
-q

The drive's capacity should be located at bytes 1C8 - 1CF.

Here are Find-ATA.exe and the results of my own experimentation with
smaller drives:
http://www.users.on.net/~fzabkar/IDE-identify/

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.