You can find much more detailed information on the subject. I'm just 
giving you my thoughts on them since I had a user try to install
an operating system on a Logical Partiton. I would have assumed
that most people would research a little more if they are planning
to dual boot on a single or even a second hard drive.  His email 
is at the bottom of this page.



Logical partitions are great to techs or people who swap their hards
drive alot or via a docking device. In Windows, a logical drive will
take the next drive assignment, this means it won't move your cd-rom
anywhere. I use this type of partition also when I take a little off
the drive to make a tmp dive so it wont change my d: cd-rom to e: and
break some older apps I use. So I make them logical. If you use a 
primary it will take the first drive assignment accorring to the
way it is connected on the bus. Which you can change with some 
effort by not always. 

Linux like any other OS will not boot from a Logical Partition. You
know other wise let me know.


By no means would I suggest ever installing on a logical partition. This
user must have created his own partition and thought it should work. If I
would have wrote this sooner he may have wasted so much time.

--------------------------------------------------------------------
Hi,
 
I had some issues regarding your instructions for dual booting Linux
via the NT bootloader (NTLDR) and a copy, bootsect.lnx, of the Linux
bootsector stored on an NTFS driver. This is on a fresh installation
of RedHat 8.0 with GRUB installed to the Linux partition (as 
recommended explicitly in the on-screen 8.0 help for "NT").
 
Original problem was the infamous blinking cursor problem when I
tried to book into Linux via the NT bootloader. Repeating the procedure
didn't help.
 
I traced this to the fact that bootsect.lnx contained 512 zero-bytes.
Which doesn't help much as a boot sector.
 
Thus
    dd = if/dev/hda5 of=/bootsect.lnx bs=512 count=1
clearly wasn't working for me. dd does give
reliable looking file contents for my 3 NTFS drives.
 
I then studied the various boot sectors per partition using a
Windows utility (Acronic disk editor v6.0 - free in a real-only demo
version). My hypothesis about what is going on is pretty simple:
 
I installed Linux to an extended partition (or more precisely to a logical
partition located inside an extended partition). Reason: simply because
I had installed my 3 NTFS partitions in front of the Linux one.
It seems that these logical partitions do not have a boot sector installed!
This seems plausible because, without a boot manager like GRUB
you won't be able to boot from an extended partition anyway.
And apparently GRUB (e.g. if installed in the MBR) manages to boot Linux 
in an extended partition anyway. The latter is plausible: GRUB is big
enough to include the hundreds of bytes of code included in the boot
loader anyway.
 
How certain am I about all this? The only thing that worries me a little
is that I do not understand the "partition type" code which the Acronic
tool shows for the logical partition. It states code 06h=FAT16
rather than 83h=Linux Ext2. On the other hand, the start and end
data about tracks and LBA sector numbers look quite alright. I have
no explanation for the strange partition type code (other than "maybe
somebody decided not to fill it properly because that somebody didn't
expect a boot loader to look at it").
 
Just thought I would let you know. I can solve this myself in various ways
(each avoiding the combination of using a bootsect.lnx file together
with Linux on an extended partition).
 
Any comments are welcome.
You can post any or all of this E-mail to your web site if your like (to
save posterity some time).
 
It is amazing that the dual boot NT/Linux problem is still solved at
such a crude level.
---------------------------------------------------------------------------

Why?