Terminology
The term BIOS (Basic Input/Output System) was invented by Gary Kildall and first appeared in the CP/M operating system in 1975, describing the machine-specific part of CP/M loaded during boot time that interfaces directly with the hardware (a CP/M machine usually has only a simple boot loader in its ROM). Later versions of CP/M (as well as Concurrent CP/M, Concurrent DOS, DOS Plus, Multiuser DOS, System Manager and REAL/32) come with an XIOS (Extended Input/Output System) instead of the BIOS. Most versions of DOS have a file called "IO.SYS", "IBMBIO.COM", "IBMBIO.SYS", or "DRBIOS.SYS"; this file is known as the "DOS BIOS", which is analogous to the "CP/M BIOS".
Among other classes of computers, the generic terms boot monitor, boot loader, and boot ROM have been commonly used. Some Sun and PowerPC-based computers use Open Firmware for this purpose. There are a few alternatives for "Legacy BIOS" in the x86 world: Extensible Firmware Interface, Open Firmware (used on the OLPC XO-1), and coreboot.
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