Info 1410 Tutorial 4 Essay

1299 Words Jun 6th, 2012 6 Pages
INFO 1410 Tutorial 4 1 What are the advantages of using a glass substrate for a magnetic disk? Improvement in the uniformity of the magnetic film surface to increase disk reliability. A significant reduction in overall surface defects to help reduce read/write errors. Ability to support lower fly heights (described subsequently). Better stiffness to reduce disk dynamics. Greater ability to withstand shock and damage Explain the difference between a simple CAV system and a multiple zoned recording system For the constant angular velocity (CAV) system, the number of bits per track is constant. An increase in density is achieved with multiple zoned recording, in which the surface is divided into a number of zones, with zones farther from the …show more content…
2. Data are distributed across the physical drives of an array. 3. Redundant disk capacity is used to store parity information, which guarantees data recoverability in case of a disk failure. Briefly define the RAID levels 0 and level 1 0: Non-redundant 1: Mirrored; every disk has a mirror disk containing the same data. Explain the terms striped data The disk is divided into strips; these strips may be physical blocks, sectors, or some other unit. The strips are mapped round robin to consecutive array members. A set of logically consecutive strips that maps exactly one strip to each array member is referred to as a stripe.

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How is redundancy achieved in a RAID system? For RAID level 1, redundancy is achieved by having two identical copies of all data. For higher levels, redundancy is achieved by the use of error-correcting codes.

10 In the context of RAID, what is the distinction between parallel access and independent access? In a parallel access array, all member disks participate in the execution of every I/O request. Typically, the spindles of the individual drives are synchronized so that each disk head is in the same position on each disk at any given time. In an independent access array, each member disk operates independently, so that separate I/O requests can be satisfied in parallel. 11 What is the difference between CAV and CLV? For the constant angular velocity (CAV) system, the number of bits per track is constant. At a constant

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