Disk Partitions

I am reminding myself of how disk partitions work, and how they can be manipulated. The impetus for this is an attempt to load Windows XP Embedded (XPe) on my target machine, an ASUS Pundit. Using Acronis Disk Director Suite, ($49.00) I created a separate small partition for the XPe installation. The problem then was trying to figure out how to boot the extra partition.

Partitions can be marked several ways
a. Active Primary – this is the boot partition. There can only be one of these on a disk.
b. Primary – This can be either a bootable partition, or not.
c. Extended – A physical partition that can be further subdivided into other partitions.
d. Logical – A subdivision of an extended partition.

The upshot for the test machine is that I want to have two partitions; one for the original Windows and software installation, that includes all of the necessary application software and a second testing partition for the Windows XPe image which contains all the applications and drivers already burnt into the XPe image.

Also, I need to be able to designate one partion or the other as the boot partition. This is done by marking the partiion as “Active”, and insuring that the boot drive letter is designated drive C:. The first part, designating the partition as the boot partition, seems to work fine within the Acronis program. Changing the drive letter, on the other hand, does not seem to be so intuitive as it involves a registry edit.

The drive letter desgination is important, because many programs rely on the designated drive letter to find their own executables and data.

To boot the XPe partition, I changed it to the “active” partition, and then renamed the drive letter to C: A final change involved changing the Boot.ini file which is present in the root directory of the partition. This file looks like this:

[boot loader]
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)WINDOWS="Microsoft Windows
XP Embedded" /fastdetect /noexecute=AlwaysOff

and it gets modified to change partition(1) to partition(2) in both instances, so that the boot designated boot partition is indeed the 2nd partition on the drive. I recall from my distant MCP days, that although disk drives are numbered beginning with 0, the partitions are numbered beginning with 1. The diagnostic for this is that if you have already designated the second partition as active, but still boot into the “wrong” partition, it means that the OS files that are loaded are the ones that are pointed to be the boot.ini. To make this even more confusing, there is the notion of the “system” partition and the “boot” partition. This is a distinction which I think is only talked about when dealing with Microsoft operating systems. Perversly, the names seem to be reversed….it is the “system” partition which contains NTLDR and boot.ini. and the “boot” partition which contains \Windows, and \Windows\System32, and all the operating system binary files.

In 99% of the cases, of course these files are are all on the same partition and in most cases there is a single partition on a drive anyway.

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