Hitachi AMS 2000 Series Service Manual page 188

RAID 6
An extension of the RAID 5 array that allows for two simultaneous drive
failures without downtime or data loss.
RPO
Recovery Point Objective. After a recovery operation, the recovery point
objective is the maximum desired time period, prior to a disaster, in
which changes to data may be lost. This measure determines up to
what point in time data should be recovered. Data changes preceding
the disaster are preserved by recovery.
S
SAN
Storage Area Network. A network of shared storage devices that
contain disks for storing data.
SAS
Serial Attached SCSI. An evolution of parallel SCSI into a point-to-point
serial peripheral interface in which controllers are linked directly to disk
drives. SAS delivers improved performance over traditional SCSI
because SAS enables up to 128 devices of different sizes and types to
be connected simultaneously.
SATA
Serial ATA is a computer bus technology primarily designed for the
transfer of data to and from hard disks and optical drives. SATA is the
evolution of the legacy Advanced Technology Attachment (ATA)
interface from a parallel bus to serial connection architecture.
SCSI
Small Computer System Interface. A parallel interface standard that
provides faster data transmission rates than standard serial and parallel
ports.
Session
A series of communications or exchanges of data between two end
points that occurs during the span of a single connection. The session
begins when the connection is established at both ends, and terminates
when the connection is ended. For some applications each session is
related to a particular port. In this document a session is the exchange
of data between groups of primary and secondary volumes.
SMTP
Simple Mail Transfer Protocol. A protocol used to receive and store
email data directly from email servers.
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Hitachi AMS 2000 Family Storage System Service Guide
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