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expansion slot
A connector on the system board used for adding option cards.
fault-tolerant
Resistant to failure. For example, a RAID 1 mirrored subsystem is fault-tolerant
because it can still provide disk I/O if one of the disk drives in a mirrored system
fails.
firmware
A computer program or instruction, such as a microprogram, used so often that it is
stored in read-only memory instead of being included in software.
floppy disk
A portable, removable disk storage device used to store programs and files.
format
a process that prepares a disk to hold data.
hard disk drives
Disk storage devices used to store programs and files.
host system
Any computer that disks are directly attached to. Mainframes, servers,
workstations, and personal computers can all be considered host systems.
hotspare
One of the most important features the controller provides to achieve automatic,
non-stop service with a high degree of fault tolerance. Rebuild occurs when a SCSI
disk drive fails and both of the following conditions are true: (1) A standby SCSI
disk drive of identical size is found attached to the same controller; and (2) All of
the system drives that are dependent on the failed disk are redundant system drives,
for example, RAID 1, RAID 2, RAID 5.
hot swap
Replacing a defective unit in a disk subsystem while the subsystem is running
(performing its normal functions). Hot swaps are manual.
Light Emitting Diode (LED)
A light on the control panel to indicate power, disk activity, or system status.
logical drive
A set of contiguous blocks on a physical disk drive. Logical drives are used in array
implementations as part of logical volumes or partitions. Logical drives are
normally transparent to the host environment, except when the array containing
them is being configured. Logical drive and system drive are used interchangeably.
