Various bits snipped...
Edit: I'd like to learn also on how to dual boot eCS and Windows Xp. Can someone point me to a tutorial ?

I bet you do not mean the above which would require WindowsXP being installed on a FAT16 drive - Dual boot allows OS/2 to boot DOS without shutting down OS/2; as long as OS/2 is installed on a FAT16 drive. Long time since I used that (Warp3, 1993/4?) but I seem to recall if you Dual Booted DOS the OS/2 system hibernated to disk until DOS was closed.
I think you mean that you want to have a choice of systems to use at bootup. Fairly simple, just requires the use of Boot Manager.
You probably already have WinXP installed in the 1st primary partition on the existing drive. If that is the case I suggest using some Windows software (Partition Magic is mentioned in another post) to create a 7Mb partition before the WinXP partition in which to install Boot Manager. If you do not already have Partition Magic or similar you could check what is being given away free on cd/dvds attached to pc magazines or checkout DFSee
www.dfsee.comBoot Manager + WinXP uses up your 2 Primary partitions for the drive so any other partition to use must be Logical; eCS installs to logical drives usually without any problems.
Just to digress slightly: Having had a look at the drives you list
C:\ = 10.8 GB = Windows Xp Professional SP2
D:\ = 19.5 GB
E:\ = 21.4 GB
F:\ = 22.7 GB
I am going to suggest some changes as none of those disk sizes is really good for an eCS boot drive - in my view.
eCS installs into around 700Mb of disk space with most options selected.
Data and Programs should be installed to different drives - this makes backing up/restoring/upgrading the eCS system much easier with minimal time spent reinstalling apps after such an event.
My suggestion would be for the following disk sizes(leaving D: to be setup as either Windows use only or possibly formatted FAT32 and used as a drive accessible by both operating systems):-
E: 2Gb eCS Boot volume
F: 10Gb Programs - probably fit all useful and nearly-useful eCS (OS/2) apps and utils into that size disk with space left over :-)
G: 12Gb User Data - things like application user profiles and configuration, documents, images, movies, audio files
Having Programs and Data separate from the boot drive makes backing up/restoring/upgrading the eCS system much easier with minimal time spent reinstalling apps after such an event. Yes, you could have Programs and Data on the same drive eg F: 22Gb but do keep the boot drive separate.
With such a small boot drive it is fairly easy to backup; the easiest option here is to boot to the command line and utilise a useful system supplied program called XCOPY.
Here is an how I would make a quick copy of my boot drive:-
Start/Reboot pc
At Boot Manager select eCS, press Enter and *Immediately* press key combination Alt-F1 - keep pressing until pc beeps
At the next menu select Boot to command line
When the system has booted to a command prompt it is possible to use xcopy to copy the complete drive elsewhere using this line where h: is the drive to copy and k:\hdrive\15022008 is where to copy to.
[H:]xcopy h:\* k:\hdrive\15022008\* /s /e /v /h /t /r
To copy all those files back to a reformatted H: drive in the event of some sort of disk/system failure:-
[H:]xcopy k:\hdrive\15022008\* h:\* /s /e /v /h /t /r
Only takes a couple of minutes on a reasonably fast system
I'll let you investigate what all the xcopy /switches are for :-)
Regards
Pete