I have WinXP Pro SP2 on first disk /dev/hda, which my BIOS currently has as first boot device.

I have CentOS-5.2-x86_64 on second disk /dev/hdb, which I can boot into if I set my BIOS to boot from this HDD. It is using LVM with vg00 and a single LV for root (/) filesystem (ext3).

How do I get bootsector file from the CentOS distro so that I can add it into WinXP's boot.ini file? I tried:
and copied the bootsect.lnx file to C:\bootsect.lnx, after which I added the following line to boot.ini in XP:
However, when selecting CentOS 5 from NTLDR boot menu, it just hangs with a black screen.

Second question is, how to get:
(a) WinXP to read/write the ext3 filesystem (from the vg00 LV) on /dev/hdb, it currently shows up in WinXP as a RAW drive G:\
(b) CentOS to read/write to and from WinXP's C:\

In the end, I basically want, WinXP's NTLDR to handle booting and I want each OS to be able to read/write to each other.

You copied too many bytes and overwrote the partition table (or part of it). You should copy only 384 bytes in your dd command. Until then, all bets are off. Hopefully you made a backup copy of the boot sector?

Just to clarify, there is no problem with either OS, I can boot into them fine, but I need to tell my BIOS which HDD to boot from.

The problem is the bootsect.lnx file which the NTLDR boots from, which when selected, doesn't boot into CentOS as expected. I will try:
and see if that helps.

Okay, I re-read your post. Normally, I don't use the NTLDR that way. I used a different format and told the NTLDR to boot off the corresponding partition/drive and let the CENTOS boot sector take care of business from there.

I like rehl as 5.0

What @otheus is alluding to IS that the boot loader that comes with modern Redhat(& others) is GRUB & it detects the presence of a windows partition & creating a boot menu entry for it.

Which is why *most* implementations install XP first then Linux. I've used your method many moons ago which worked for me, then GRUB came along
(ps. don't uprade\install vista on the same HD as linux, vista can't co-exist)

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ms. stevi

Actually, I was alluding to the fact that (1)
is NOT a valid NTLOADER line from what I have seen. And further (2), NTLOADER doesn't directly load Linux: grub loads linux. What NTLOADER can do (I Think) is to load the boot sector as if the BIOS had just loaded a boot sector, and in that case, the boot sector would contain the boot-strap code that GRUB uses.

But Stevie Velvet is probably correct: easier to use Grub to load windows, perhaps, than the other way around.