Make a USB hard drive bootable
March 3, 2006
Needed:
USB hard drive enclosure, IDE hard drive, DOS bootdisk with fdisk and format utilities, PC with BIOS capable of booting off a USB hard drive
Procedure:
Place the DOS bootdisk in the floppy drive. Power on the PC, go into BIOS and temporarily disable the hard drives and CD/DVD drives. Change the boot order to floppy drive first then USB device. Save BIOS settings, reboot and the computer should boot off the DOS bootdisk. Run fdisk, create a partition on the USB drive, make it active, exit fdisk, reboot the PC with the DOS bootdisk still in the drive and run fdisk with the /mbr switch. Format the USB partition with format c: /u/s. Remove the DOS bootdisk from the floppy drive and reboot the computer. It should boot off the USB hard drive and you should have a DOS prompt. Reboot the PC, go into BIOS, re-enable the hard drive(s) and CD/DVD drive(s), save the settings, reboot the computer. To test booting off the USB drive, hit your Boot Devices List magic key( F12 or F11 on some PCs ) and choose the USB hard drive.
Explanation:
By disabling the hard drives and CD/DVD drives in the BIOS, the USB drive will temporarily become drive C: when using fdisk. Hence, you can now create a partition on the USB drive, make it active, give it a Master Boot Record, and format it. So now when you display the Boot devices menu for the PC, you can boot off the USB drive. I use mine for imaging computers at work with Norton Ghost. I keep all the ghost images in the 20GB USB drive. With the USB drive bootable, there is no need for a DOS bootdisk with USB drivers.
Gotchas:
I ran into just one issue: do not use a DOS bootdisk that loads USB drivers. 1. USB drivers are not needed if your BIOS supports booting off USB devices. 2. fdisk will wrongly report that your USB drive contains 2 different partitions. For example, if your USB drive is 20GB in size, fdisk will report 2 separate 20GB areas are available for use. I can only assume fdisk is getting the drive sizes from two sources at once: the BIOS and the USB drivers.
