With 28-bit LBA BIOS (non-upgradable) can I use 160GB HD on XP Sp2?

[JS]

I recently upgraded my notebook with a 160GB hard disk. However in BIOS I
see only 137GB. I know it is because the BIOS is only so-called '28bit' LBA.
The notebook is of 4 years old and there will be no more BIOS update.
When I install XP (SP2) on this HD, I still see 160GB in XP. I heard it is
because the driver in XP SP2 (atapi.sys) is 48-bit LBA already so it can
recognize and access all 160GB disk.
But does this mean I can ignore the BIOS limitation and fully utilize 160GB
in XP? I also heard some people with similar HD upgrade suffered data loss
or system destruction because as something in the system doesn't support
48-bit, when writing to disk, it wraps back to first tracks and destroys
MBR, boot sectors etc. But I don't know whether it was because BIOS didn't
support 48-bit.
So my question is, with 28-bit BIOS, can I safely use 160GB disk with XP
Sp2?
I read many articles, including Microsoft ones, that state that besides the
OS 48-bit LBA support, BIOS must also support 48-bit LBA. But I also heard
that, BIOS is only active when booting up the PC, once it passes to OS, it
should be the OS that manages the disk. So, even though in BIOS I see only
137GB, it should not affect OS activities as long as OS supports 48-bit LBA.
So I am a bit confused: As OS can recognize 160GB, why BIOS matters? In what
situation can a 28-bit LBA BIOS destroy a 160GB disk?
I heard that some people say 'as long as the midpoint of the partition falls
below 137GB, the BIOS will be able to boot from that partition' because the
midpoint is where the MFT mirror is stored. But in XP the MFT mirror is
stored at the end of partition?

 

[Guest]

This is too big a subject to reply on here, check out www.48bitLBA.com for a
whole host of articles and tools that will probably answer your questions.

HTH

Neil
www.nwarwick.co.uk

 

[JS]

I have already gone through that website. One thing I don't understand is
that when my notebook BIOS only sees 137GB, XP sees 160GB. And I am asking
in this case can I use full 160GB in XP. Why many people says I need both
BIOS and OS to support 48-bit?

 

[DL]

Both Bios & XP is needed to support large hd's
I'm surprised your bios doesn't support large hd's
Your bios is set to auto detect for the hd?

If indeed it doesn't support large hd's simply partition the hd eg a 30gb
partition for winxp and then create a partition in the free space.
NB in this config you would have to custom install any apps so they are
installed on the 'other' drive, also move My Documents to the other drive.
Or a win partition of 120gb and then a partition in the free space

 

[JS]

Actually I want to know why both Bios & XP are needed to support large hd's.
Xp can see large HD already.
Partitioning is not the solution. At the backend disk is accessed by
absolute sector numbers, which doesn't change no matter how partitions are
created.

 

[DL]

If the Bios doesnt support large HD's than you risk File corruption

If the Bios supports large hd's but your installation version of Win doesnt,
then if you create a partition with win cd, then once installed and updated,
create a further partition in the free space, there is, I have read, a
*theoretical possibility* of corruption in the new partition.

You can allways create a slipstreamed copy of win installation cd that
contains the latest sp, and cosequently supports large hd's

 

[JS]

If xp supports large HD but bios doesn't, under which cases there will be
data corruption? Does xp pass back data manipulation to bios?

 

[DL]

refer to this, I havent bothered to explore the technical reasons.
http://support.microsoft.com/default.aspx?scid=kb;en-us;303013&Product=winxp

 

[JS]

I have read this before. It says > 137GB area shall not be addressable if
BIOS doesn't support 48-bit LBA, but it is not the case for me. I see 160GB
in XP and 137GB in BIOS, I cannot find further explanations why this could
occur.