Monday, December 1, 2003		ITerminology

Lost cluster: Also called a lost allocation unit, or a lost file fragment. A data fragment that does not belong to any file, according to the system’s file management system, and, therefore, is not associated with a file name in the file allocation table. Lost clusters can result from files not being closed properly, from shutting down a computer without first closing an application or from ejecting a storage medium, such as a floppy disk, from the disk drive while the drive is reading or writing.

BGA: Short for ball grid array, a surface-mount integrated circuit package in which the die is attached to the printed circuit board with either plastic or ceramic solder balls instead of metal leads that are used in other packaging. BGA is similar to PGA packaging, but the pins are replaced with balls of solder to allow more contact points between the die and the circuit board.

System disk: Another name for a bootable diskette, a floppy disk (or CD-ROM) that a computer can use to boot the operating system (OS) if the hard drive fails to boot the OS. Typically, PCs will read the floppy disk drive before the hard drive when booting, so if the user leaves a floppy disk in the drive that does not contain the operating system or another control program, the computer will display a system disk error. The user can change the system BIOS so that the hard drive is read before the floppy drive.