Well. . not exactly. DOS doesn't have to be
installed just loaded into memory. Works pretty much like any Live CD. As long as the boot files are on the appropriate sector on the optical disc, a BIOS will load the media just fine.
Swallowed my pride and looked at what Bart has to say about it:
Clean Bootable CD-Rom (for BIOS upgrade) [updated! may 6, 2005]
People ask me if it is possible to create a bootable CD-Rom to update/flash their BIOS, on a system that has no floppy disk drive. I realize that some new PC's nowadays also don't have a floppy drive so this problem may affect more people in future... I have re-done this CD, so that it will be easier to use (single download package). It uses an updated version of BCD and BFD.
This Clean Bootable CD-Rom can be used for flashing your BIOS or other programs that need to be run from a "clean-booted" Dos operating system.
The steps to create are:
Download Clean Boot CD package v2.0 (596KB) and unpack it into any directory you like.
Add your own files, needed to upgrade your BIOS, to the cds\clean\bootdisk\ folder. You have about 2.5MB available space on the bootimage (the CD uses 2.88MB floppy emulation). Do not add your files to cds\clean\files\ folder!
Optionally you can edit the file cds\clean\bootdisk\autorun.bat and append a line to automatically run your flash program.
When you're done customizing, run "build-clean.cmd" to build your ISO image and burn it to your CD writer.
Warning: Use this Clean Bootable CD-Rom at your own risk!
http://www.nu2.nu/bootcd/
Also, I forgot about another useful utility: the virtual floppy drive. Sometimes, depending on how you create you bootable CD, a program might ask for a bootable floppy to be inserted into your floppy drive. Well, what if you don't have one? Enter the virtual floppy drive. There are a couple programs floating around the Interweb; but, the one I've used most often is the aptly named
Virtual Floppy Drive [current version: 2.1] from VM Back.
[EDIT: Duh! You might also like or need ISO Recorder. On Vista, allows one to burn DVD iso, as well.]