Installation guide

Manual Number 775012 G-1
Glossary
Battery Backup Unit
See “Intelligent Battery Backup Unit.”
Cache
Controller memory used to speed up data transfer to and from a disk.
Cache Flush
Refers to an operation where all unwritten blocks in a Write-Back Cache are
written to the target disk. This operation is necessary before powering down
the system.
Cache Line Size
See “Segment Size.”
Channel
Refers to one SCSI bus on a disk array controller. Each disk array controller
provides at least one channel.
Consistency Check
Refers to a process where the integrity of redundant data is verified. For
example, a consistency check of a mirrored drive will make sure that the data
on both drives of the mirrored pair is exactly the same. For RAID Level 5
redundancy, a consistency “connect” is a function that allows a target SCSI
device (typically a disk drive that received a request to perform a relatively
long I/O operation) to release the SCSI bus so that the controller can send
commands to other devices. When the operation is complete and the SCSI
bus is needed by the disconnected target again, it is “reconnected.”