Embedded software contained in EPROM or flash memory. It isn't quite hardware, but at least doesn't have to be loaded from a disk like regular software. Hacker usage differs from straight techspeak in that hackers don't normally apply it to stuff that you can't possibly get at, such as the program that runs a pocket calculator. Instead, it implies that the firmware could be changed, even if doing so would mean opening a box and plugging in a new chip. A computer's BIOS is the classic example, although nowadays there is firmware in disk controllers, modems, video cards and even CD-ROM drives.