El Torito is a specification that specifies how CD-ROMs should be formatted so that computers that have been set up for this through a corresponding BIOS can boot directly from CD-ROM without the prior installation of an operating system on the hard disk drive .
- Booting a bit-by-bit copy of a hard drive
- Booting a bit-by-bit copy of a floppy
- Booting a program code
When starting the hard disk copy, an MS-DOS or Windows-compatible operating system designates the drive with the CD-ROM as C : . All other hard disks begin with D :. The more robust variant is the start from a floppy image (on the CD). In this case, the CD-ROM is labeled A: from an MS-DOS or Windows compatible operating system. The original floppy drive A: can then be addressed with B : .
The program code, on the other hand, is loaded directly into the memory when started and executed there. This option is often used by boot loaders .