Glossary

The glossary below contains many of the terms you will find in common use throughout the Symantec Security Response website. Please refer to this list to find definitions of terms and answers to other Internet security-related questions.

parity

An integer’s quality of being odd or even. See also parity bit, parity checking.

Redundant information that is associated with a block of information. Parity is a calculated value used to reconstruct data after a failure.

RAID-5 volumes stripe data and parity intermittently across a set of disks. Within each stripe, the data on one disk is parity data and the data on the other disks is normal data. RAID-5 volumes, therefore, require at least three disks to allow for this extra parity information. When a disk fails, the parity information on the good disks can be used to recreate the data on the failed disk.

A calculated value that can be used to reconstruct data after a failure. While data is being written to a RAID-5 volume, parity is also calculated by performing an exclusive OR (XOR) procedure on data. The resulting parity is then written to the volume. If a portion of a RAID-5 volume fails, the data that was on that portion of the failed volume can be recreated from the remaining data and the parity.

Redundant information that is associated with a block of information. Parity is a calculated value used to reconstruct data after a failure.

RAID-5 volumes stripe data and parity intermittently across a set of disks. Within each stripe, the data on one disk is parity data and the data on the other disks is normal data. RAID-5 volumes, therefore, require at least three disks to allow for this extra parity information. When a disk fails, Symantec software uses the parity information on the good disks to recreate the data on the failed disk.

See RAID-5 Volume.