In order to do that your motherboard should support boot from USB, Fireware or E-SATA. If it does, you need to go to BIOS options and choose option "Boot from USB device..." or something like that. E-SATA and should be available as any other hard drive. Same is true for Fireware.
Your Bios has an option to boot from your DVD Drive or external drive. If the internal or external drive has no boot sector or disc with a boot sector the system will not boot. You will need to go into your bios at boot time most often by tapping your delete key or whatever option your motherboard bios requires and change the option back to boot from your hard drive.
binary data, it can be on the hard drive, BIOS, or any external or internal device like a flash drive, built-in drivers
Some motherboards support boot from external USB drive amd/or eSATA. You need to check BIOS settings (the external drive should connected) to make sure that your computer is capable to do so. It the motherboard is capable then you can install operating system on the external drive (if it's an usb drive be ready for low performance).
hard drive
The fastest type of external hard drive would be a external 3.0 USB hard drive.
You get another memory storage device, such as an external hard drive, and you copy everything on your hard drive onto the external hard drive, and keep it safe. That way, if your hard drive crashes, then you can take it out, and plug your external hard drive in, and work from that.
You should be able to select the boot order from the bios, check the order in the bios
IDE 0 always has the designation C. Its a throwback to the days when computers were single or dual floppy drive only and they had (and still have) designations A and B. Hook up the external drive, go into the BIOS and select the external as the drive to boot from. Save the change and allow the computer to boot. Load the OS and it should defer to the external drive.
You can completely clear your external hard drive by formatting it.
---- # go to "my computer" # browse to your external hard drive # then open another "my computer" window # drag and drop the file(s) you want to the window displaying the external hard drive. ----
hard drive type
you can go to the service center of your external hard drive.