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Glossary
Write-back Cache . Many modern disk controllers have several megabytes of cache on board.
Inboard cache gives the controller greater freedom in scheduling reads and writes to disks attached
to the controller. In write-back mode, the controller reports a write operation as complete as soon
as the data is in the cache. This sequence improves write performance at the expense of reliability.
Power failures or system crashes can result in lost data in the cache, possibly corrupting the file
system.
Write-through Cache . The opposite of write-back. When running in a write-through mode, the
controller will not report a write as complete until it is written to the disk drives. This sequence
reduces read/write performance by forcing the controller to suspend an operation while it satisfies
the write request.
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