Unformatted text preview: g is usually done at the hardware level Block 0 is <0,0,0>. Mapping proceeds sequentially through a track, then the rest of the tracks in a cylinder, and then through the rest of the cylinders from outermost to innermost. Magnetic Disk Fundamentals Many configurations possible Example: an 80GB drive might have 32,768 cylinders, 80 tracks per cylinder, 63 sectors per track, 512 bytes per sector Disk drives rotate at 5,000 to 15,000 RPM Speed (slowness) depends on mechanics of the drive each of the 16,777,216 sectors has a block number The block number is used by the I/O unit The disk controller (hardware) maps block number to <cylinder,track,sector> Transfer rate : speed of data transfer between disk drive and computer Magnetic Disk Fundamentals
Disk bandwidth is the (total number of bytes transferred) / (total time from first request for service to completion of transfer). Access time : has two major components Se...
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- Spring '08
- Operating Systems, Input/output, disk drives, Elevator algorithm, I/O scheduling, request queue, CFQ