Active partitions, Volume Lettering etc.

[jfradley]

I'm using diskpart to manage the partitions on my XPE
disk. I'm going to have multiple partitions/volumes on my
harddrive to store past OS installs (just in case an
update crashes). So, I'm creating partition, assigning
volume letters, making partitions active and realize I
don't really know much about all this stuff. I know the
basics but when stuff goes wrong, I don't have the
background in fully troubleshoot.

I know this is a little beyond general XPE questions, but
does anybody have a link to good website that explains all
this. If not maybe you can answer these questions,

1) Can you have more then one primary partition on a disk?
I've seem to be able to do this with diskpart, but then
why is it called primary if we can have two?

2) Can you have more then one active partition on a disk?
This I can't seem to do. With two partitions, every time I
make one active the other goes inactive.

3) Can I assign non-contiguous volume letters, such as
partition 1 = C: and partition 2 = P:? This I haven't been
able to do.

Thanks for any info.

 

[Slobodan Brcin]

1. You can have 4 primary partitions in one MBR block so this is one disk
limitation.
2. No. Only one. This tell MBR what PBR to load during the boot.
3.Yes.
http://www.microsoft.com/windows/embedded/community/tips/xp/runtimepartition
..asp

Regards,
Slobodan

 

[Guest]

Thanks slobodan,

That clears up some questions. I read the article but I
don't think it will help me in my situation. It appears
you have to know the partition strucure before the build.

What I want to do is,

On clean install
1) create two primary partitions, C: and P: ( Current and
Previous )
2) copy XPE to the first
3) Set 1st partition active

On update
1) copy data from C: to P:
2) copy new OS onto C:

On swapver (this will revert to last install)
1) re-assign partition 2 to C:
2) re-assign partition 1 to P:
3) make partition 2 active


I have two partitions with same build. I tried just
changing the active partitions alone to accomplish the
swapver. Didn't work. I realized they both have still have
the same boot.ini. So, I changed Partition 2 boot.ini to
boot from 2nd partition. And it works, only it comes up
saying drive E: not C:.

So, do you think I need to change not only the active
partition and boot.ini but also some registry values in
order to accomplish my desired functionality?

 

[Slobodan Brcin]

First to make clear few things:

Partitions are not C: D:, partitions are named
multi(0)disk(0)rdisk(0)partition(1), multi(0)disk(0)rdisk(0)partition(2) or
in windows case they are mapped like article says.

So basically you must swap partition entries in MBR for partition 1 to
change position with partition 2.
Also in this process you must set new partition 1 active, one byte in MBR
block.
For testing purposes you can use diskedit.exe from Symantec.

And concerning the XPe you should at least delete all entries in
HKLM\System\MountedDevices. before shutting down working image.

This is all to complicated and you can do it simpler.

If you need to revert to old version just copy it from backup partition to
boot partition.
Of course you are aware that you must use third OS (Booted from CD) to be
able to do all of this in both approaches.

Regards,
Slobodan

 

[Guest]

Thanks for the info. I wanted to avoid doing a copy
because of the time it would take and it would overwrite
the current partition. I would need a thrid temp partition.

I think I'm straying away from having multiple partitions.
Like you said, it's getting a little complicated for a
simple function. I think I'm just going to use one
partition. And I'll archive the previous OS install into a
folder. Something like c:\previous. Then I'll just have a
batch file that will swap/rename the contents of c:\ and
c:\previous.

Thanks again.