Do I need 48-bit addressing if I partition?

[Lupine]

I'm getting conflicting recommendations regarding XP support for my WD2000JB
hard disk. Here's what I have:

1. XP SP1 (slipstreamed)
2. nForce2 motherboard (bios supports 48-bit addressing)
3. WD2000JB (200GB) installed on IDE0

Some recommendations say that I need to add 48-bit support within the
registry to support this hard disk no matter what. Others suggest that this
only applies if the system partition is >137GB.

So, what is the truth behind 48-bit addressing? I DO have multiple <137GB
partitions and I DO NOT currently have 48-bit addressing enabled, yet can
see the entire drive. My concern is data corruption, so I need to know
which setting is appropriate for my multi-partition setup.

Thanks!

Lupine

--
WinXP SP1 & RH Linux 8.0 | Antec 1080AMG & 550W TruePower | Asus
A7N8X-Deluxe | AMD Athlon XP 1800+ Palomino | Zalman CPNS6000Cu | Crucial
256MB PC2700 DDR x2 | Radeon 9700 Pro 128MB | DX9 & Cat3.1 | Western Digital
WD2000JB | Plextor PX-320A CDRW/DVD | Plextor PX-W4824A CDRW | SoundBlaster
Audigy2 Platinum | USR 56k V92 5686D

[Rich Barry]

My understanding is that as long as your partition is <137G and you can
see the entire drive you should be fine. But if you need to go to 48-Bit.
Most problems occur when your full drive is not seen by fdisk and/or bios.
Have you seen this
http://support.microsoft.com/default.aspx?scid=kb;en-us;303013
"Lupine" > wrote in message
...
> I'm getting conflicting recommendations regarding XP support for my
WD2000JB
> hard disk. Here's what I have:
>
> 1. XP SP1 (slipstreamed)
> 2. nForce2 motherboard (bios supports 48-bit addressing)
> 3. WD2000JB (200GB) installed on IDE0
>
> Some recommendations say that I need to add 48-bit support within the
> registry to support this hard disk no matter what. Others suggest that
this
> only applies if the system partition is >137GB.
>
> So, what is the truth behind 48-bit addressing? I DO have multiple <137GB
> partitions and I DO NOT currently have 48-bit addressing enabled, yet can
> see the entire drive. My concern is data corruption, so I need to know
> which setting is appropriate for my multi-partition setup.
>
> Thanks!
>
> Lupine
>
> --
> WinXP SP1 & RH Linux 8.0 | Antec 1080AMG & 550W TruePower | Asus
> A7N8X-Deluxe | AMD Athlon XP 1800+ Palomino | Zalman CPNS6000Cu | Crucial
> 256MB PC2700 DDR x2 | Radeon 9700 Pro 128MB | DX9 & Cat3.1 | Western
Digital
> WD2000JB | Plextor PX-320A CDRW/DVD | Plextor PX-W4824A CDRW |
SoundBlaster
> Audigy2 Platinum | USR 56k V92 5686D
>
>

[Joep]

Others suggest that this
> only applies if the system partition is >137GB.

I think they're wrong

--
Joep



"Lupine" > wrote in message
...
> I'm getting conflicting recommendations regarding XP support for my
WD2000JB
> hard disk. Here's what I have:
>
> 1. XP SP1 (slipstreamed)
> 2. nForce2 motherboard (bios supports 48-bit addressing)
> 3. WD2000JB (200GB) installed on IDE0
>
> Some recommendations say that I need to add 48-bit support within the
> registry to support this hard disk no matter what. Others suggest that
this
> only applies if the system partition is >137GB.
>
> So, what is the truth behind 48-bit addressing? I DO have multiple <137GB
> partitions and I DO NOT currently have 48-bit addressing enabled, yet can
> see the entire drive. My concern is data corruption, so I need to know
> which setting is appropriate for my multi-partition setup.
>
> Thanks!
>
> Lupine
>
> --
> WinXP SP1 & RH Linux 8.0 | Antec 1080AMG & 550W TruePower | Asus
> A7N8X-Deluxe | AMD Athlon XP 1800+ Palomino | Zalman CPNS6000Cu | Crucial
> 256MB PC2700 DDR x2 | Radeon 9700 Pro 128MB | DX9 & Cat3.1 | Western
Digital
> WD2000JB | Plextor PX-320A CDRW/DVD | Plextor PX-W4824A CDRW |
SoundBlaster
> Audigy2 Platinum | USR 56k V92 5686D
>
>

[Kent W. England [MVP]]

Since logical byte addressing is on a per-partition basis, if your
partitions are less than 137 GB, you don't need 48-bit addressing *and*
you will be able to see the entire disk.

Only if you want the entire 200+ GB drive on one partition do you need a
slipstreamed SP1 installation.

--
Kent W. England, Microsoft MVP for Windows



"Lupine" > wrote in
message ...
>
> So, what is the truth behind 48-bit addressing? I DO have multiple
<137GB
> partitions and I DO NOT currently have 48-bit addressing enabled, yet
can
> see the entire drive. My concern is data corruption, so I need to
know
> which setting is appropriate for my multi-partition setup.

[Joep]

> Since logical byte addressing is on a per-partition basis, if your
> partitions are less than 137 GB, you don't need 48-bit addressing *and*
> you will be able to see the entire disk.

I think you are wrong. On a low level the OS will need in the end to address
a sector on the harddisk, when this sector is > 137 Gb, it is gonna need a
48bit address regardless of how the disk is partitioned.

2 Issues:

BIOS : if you access the disk through BIOS int13h extended calls (like DOS
disk imaging programs) the bios needs to support 48bit addressing

OS : Windows OSes do not rely on BIOS for accessing disks once they
'loaded', so even if bios supports 48bit addressing the OS needs to support
it as well. Still MS claims, before enabling BigLBA your BIOS should support
48bit addressing as well.

> > see the entire drive. My concern is data corruption, so I need to
> know

Yes, you are right and should be concerned.


--
Joep



"Kent W. England [MVP]" > wrote in message
...
> Since logical byte addressing is on a per-partition basis, if your
> partitions are less than 137 GB, you don't need 48-bit addressing *and*
> you will be able to see the entire disk.
>
> Only if you want the entire 200+ GB drive on one partition do you need a
> slipstreamed SP1 installation.
>
> --
> Kent W. England, Microsoft MVP for Windows
>
>
>
> "Lupine" > wrote in
> message ...
> >
> > So, what is the truth behind 48-bit addressing? I DO have multiple
> <137GB
> > partitions and I DO NOT currently have 48-bit addressing enabled, yet
> can
> > see the entire drive. My concern is data corruption, so I need to
> know
> > which setting is appropriate for my multi-partition setup.
>

[Lupine]

"Rich Barry" > wrote in message
...
> My understanding is that as long as your partition is <137G and you can
> see the entire drive you should be fine. But if you need to go to 48-Bit.
> Most problems occur when your full drive is not seen by fdisk and/or bios.
> Have you seen this
> http://support.microsoft.com/default.aspx?scid=kb;en-us;303013

Yes, I've looked at that KBA several times, and it doesn't appear to
directly answer my question. "Should be fine" is what worries me - I don't
want data corruption to occur because I've misread or misinterpreted the
KBA.

What worries me is that apparently data corruption can occur in two
configurations: 1) I need 48-bit enabled but don't, or 2) I don't need
48-bit enabled but do.

Thanks for the response.

Lupine