Dell 760N, 720N, 740N, 2385P manual Uhdgrqo\Iloh, Uhdoprgh, Uhiuhvkudwh

sequentially across the available disks and no redundancy is provided. RAID 0 config- urations provide very high performance but relatively low reliability. RAID 0 is the best choice when DSA controller cards are duplexed. See also striping.

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RAID 1 is commonly called mirroring. RAID 1 also uses striping, so RAID 1 may be regarded as the mirroring of RAID 0 configurations. RAID 1 is the best choice in high-availability applications that require high performance or relatively low data ca- pacity. See also mirroring, RAID 10,

striping.

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RAID 4 is commonly called guarding. It uses data striping, like RAID 0, but adds a single, dedicated parity drive. The parity data stored on this drive can be used to recover data lost from a single failed drive. RAID 4 configurations write data slowly because parity data has to be generated and written to the parity drive, and the generation of the parity data frequently re- quires reading data from multiple physical drives. See also guarding and striping.

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RAID 5, like RAID 4, is commonly called guarding. RAID 5 is identical to RAID 4, except that the parity data is distributed evenly across all physical drives instead of a parity drive. In configurations using a large number of physical drives in which a large number of simultaneous small write operations are being performed, RAID 5 offers potentially higher perfor- mance than RAID 4. RAID 4 and RAID 5 configurations are appropriate in high- availability applications where perfor- mance is less critical or where high data capacity is required. See also guarding.

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RAID 10 is a mirroring technique in which data is duplicated across two identical RAID 0 arrays or hard-disk drives. All data on a physical drive in one array is duplicat- ed, or mirrored, on a drive in the second array. Mirroring offers complete redun- dancy of data for greater data security. See also mirroring, RAID 1, and striping.

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Acronym for random-access memory. The computer’s primary temporary stor- age area for program instructions and data. Each location in RAM is identified by a number called a memory address. Any information stored in RAM is lost when you turn off your computer.

5$0'$&

Acronym for random-access memory digital-to-analog converter.

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A read-only file is one that you are prohib- ited from editing or deleting. A file can have read-only status if:

‡Its read-only attribute is enabled.

‡It resides on a physically write- protected diskette.

‡It is located on a network in a directory to which the system administrator has assigned read- only rights to you.

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An operating mode supported by 80286 or higher microprocessors, real mode imitates the architecture of an 8086 microprocessor. Designed to run in real mode, MS-DOS (unassisted by additional software techniques) can address only 640 KB of conventional memory.

UHIUHVK￿UDWH

The frequency, measured in Hz, at which the screen’s horizontal lines are re- charged. A monitor’s refresh rate is also referred to as its vertical frequency.

5(1

Abbreviation for ringer equivalence number.

5),

Abbreviation for radio frequency interference.

5*%

Abbreviation for red/green/blue.

14 Dell PowerVault 720N, 740N, and 760N User’s Guide