Install Linux RedHat on External USB hard drive.

when booting off the installation media, type linux expert

if this is not successful, when you get to the first install screen, hit ctrl+alt+f2 to get to a shell, and type
modprobe usb-storage

ctrl+alt+f7 or f8 will bring you back to the install

i did what you said above but still i cannot see my usb drive in the installation screen.

Any other suggestions??

does your bios recognize your usb as a boot device... if it does not, you are out of luck

No, the bios does not recognize my USB as a boot device.

But i began the installation using "linux expert" command and now it does recognize my external usb hard drive. Should i proceed with the installation? if the installation is succesful how will i be able to boot later from the usb hard drive?

Regards.

It is a bit difficult to give advice without knowing the purpose of the exercise. To me, it looks like you have quite a few obstacles here (USB HD not a boot device; RH9 being a bit long in the tooth; pre-partitioned HD etc).

If you're just trying out Linux, you could get a new HD for your laptop and a tray for it so you could easily swap between the Windows and the Linux one. One other possibility is to get something more modern like SUSE or Ubuntu that can resize the windows partition and create a dual-boot machine for you. The external 300G HD could be used for storage from within any of the O/S's, as long as you don't make it NTFS.
/RID

Basically what i want to do is install Linux on a secondary HD because i don't want to fool with the guarantee of my laptop in case anything goes wrong.

The external HD is new and i used Partition Magic so as to create a NTFS and a Linux partitions. The HD is currently empty so there is no problem if i have to reformat and create new partitions in order to install RH9.

Basically what i want to do is to be able to select beteen Linux and Windows during boot. I have found this link, maybe you can advice me on how to do it with RH9.

http://www-128.ibm.com/developerworks/linux/library/l-fireboot.html?ca=dgr-lnxw09FireBoot

Since your bios does not recognize your usb drive as a boot device, in order to run linux off of an external usb drive, you need to setup a linux boot CD which loads your usb drivers/mass storage drivers and then points to your usb drive as the root partition..  If you want to travel down this path, it is not an easy task..  You will need to read up on how to create an "el torito" boot CD, and you'll have to modify your initrd file to load usb drivers.  
Ultimately, I would follow rid's suggestion and get a separate hd that you can swap in and out or just parition your current hard drive...

If i partition my current drive how can i make it to have an option from which O/S to boot?

The easisest way, if you're not compelled to use RH9, is to go for SUSE or Ubuntu distributions, as they offer an option to resize the windows partition and install themselves on space thus freed. I suppose other modern distributions have the same functions, but I'm not sure about RH9; the other two I have tried myself doing just this.

This kind of installation will install and use a boot-loader that gives you a choice, at startup, to boot either Linux or windows. To switch between O/S's you only have to reboot and choose again.

I know for a fact that this works OK if you let the Linux installation handle partitioning, but I have no experience with the use of other (third-party) partition managers. I'd advice against using them, unless you are very familiar with them and know the kinds of problems that may occur. A backup of any important stuff is, of course, imperative, whichever solution you choose.

/RID

i've had some success with partition magic creating my ext3 partition and then using redhat/fedora on it.     As far as I know, RH9 will not let you resize a windows partition during install.
When installing, you should install the boot loader on the mbr of your disk which will allow you to choose between linux or windows.  

Where can i find SUSE or Ubuntu? Will these distributions provide me with the same functionality as RH9?