Trying to install RHEL Version 4 (32-bit). The setup program does not detects my external storage. It only "sees" the PCs internal hard disk which is taken by Win XP. Therefore Setup assumes that I have no free storage for Linux partition and cannot continue.

Is it possible that this particular drive is not compatible with RHEL V4? Or is there something I can do beforehand to make it detectable?

Thx.

I can't envision it being the MyBook, it is possible that the RHEL only talks to IDE and SATA controllers to find storage mediums and not looking at the USB controllers. It is also possible that there is a setting in the bios to have the USB controllers more visible, perhaps setting the bios to "plug N play OS enabled" or similar. I think it is possible to have RHEL see the USB drive by having the right settings enabled in the bios. The bios is sort of fragile and should not be tampered with blindly, it would be best to visit your computer manufacturer's web site, or the mother board manufacturer's site and obtain a manual for the mother board/bios settings which can usually be downloaded in .pdf (Acrobat reader) format to get an in depth explanation of all the different options available in the settings.
Sometimes the computer manufacturer does not tell you which mother board is installed, you can open the box and see what is written in between the expansion slots, if there is some kind of model number there, it is probably an Asus mother board. Or you can just put those model numbers in the google search field and google might drop the right clues.
Just one avenue to walk in an effort to get it to happen, as I'm sure it can happen.

EDIT: Also, while you are at the manufacturer's site, check to see what the latest bios update has to offer. Most mother board manufacturers are like any other corporation, they pust the product out the door as soon as possible to beat the competition, most often there are bugs and features missed, and these features will be taken care of with a revision, if your bios has had a revision, read what features have been fixed or added to see if it applies to your situation, if so, you may want to apply the flash update for the bios.

Good point. I'll follow up on the BIOS settings. I just wanted to add a tidbit of information. The existing OS (Win XP) does detect the external storage. I carved up a small piece (10MB) for an NTFS partition and it works fine. So whatever the BIOS does makes the storage visible to Win XP, at the very least.

In that case, you should not need to look in the bios. You may however, be able to pass an argument to the kernel (kernel parameter) at the beginning of the installation to kick start it in the right direction. Because I've not had the opportunity to use parameters yet, I may not be able to give you the right option to use. Perhaps something like so: --preload usb-storage

I did do a little googling on the subject and allot of people say they had to use "expert" mode by typing "linux expert" at the prompt to get it done. There are other ways as the link below point out.
http://www.dinkercharak.com/comp/linux-usb.htm

I have had success connecting a WD Mybook 500GB Essential Edition to system rescue CD (linux on a CD). That being said, I have had trouble getting Redhat 7.2 (VMware ESX 2.5.4) to recognize the USB HDD.

Because linux recognized the WD USBHDD, I believe that there is no problem with the device: only the OS.

Hey mate
I had the same problem with my WD 120Gb portable drive.
What I did probably isn't a legitimate style fix, but it worked.

If you haven't already install Linux on ur external drive, put in the disc an enter the Options Menu (it was F2 on my FC5 cd)
When you go in there, type 'linux dd' or something similar that tries to find a driver disc
When you go into that search through the harddrives and move through them - this should find your external (my path had a choice of hda and sda. sda lead to my harddrives and sdb was my external. i went into that and found the autoplay features which confirmed that was it.)
once you go as far as finding your external, just quit out of it using back and cancel

then start up the installation and you should now be able to find your harddrive

I hope this works for you and helps

Good Luck