Product manual

CDA 7 5630 Product Manual
G-8 77 A1 69UP Rev00
SRDF for GCOS 7
This is a disaster recovery solution that maintains a mirror image of data in two CDA 7 5330-23
subsystems that are located in physically separate sites.
Stage
The process of writing data from a disk device to cache. See also the term "Destage".
Storage Control Unit (SCU)
The component in the Symmetrix subsystem that connects Symmetrix to the host channels. It
performs channel commands and communicates with the disk directors and cache. See also
Channel Director.
Striping
The process of segmenting logically sequential data and writing the segments to multiple physical
disk devices.
Synchronous Transmission
A timing protocol that uses a master clock with a clock period and allowable offset that holds the
sending and receiving devices in the desired phase relationship.
T
Target
A SCSI device that performs an operation requested by an initiator.
Terabyte
The TB
2
value is based on the convention: 1 TB = 1024x1024x1024x1024 bytes.
The TB
10
value is based on the convention: 1 TB = 1000x1000x1000x1000 bytes.
U
ULTRA SCSI
Ultra SCSI (Small Computer Systems Interface). The transmission rate is 20 MB/s in 8 bit format
and 40 MB/s in 16 bit format.
UNIX
UNIX is an interactive, multi-tasking, multi-user operating system. UNIX is written in “C”
language. There are three types of UNIX files: directories, data files, and special files. A directory
is a file containing certain information about another file. A directory contained within another
directory is a sub-directory. The two most common types of UNIX are BSD (Berkeley Software
Distribution) and System VR4 (developed by AT&T). Most UNIX systems are a “mix” of both
types.