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Unformatted text preview: le, if we visit the Web page for the IBM Ultrastar 36LZX disk, we can glean the geometry and performance information shown in Figure 6.13. Geometry attribute Platters Surfaces (heads) Sector size Zones Cylinders Recording density (max) Track density Areal density (max) Formatted capacity Value 6 12 512 bytes 11 15,110 352,000 bits/in. 20,000 tracks/in. 7040 Mbits/sq. in. 36 GBbytes Performance attribute Rotational rate Avg. rotational latency Avg. seek time Sustained transfer rate Value 10,000 RPM 2.99 ms 4.9 ms 21–36 MBytes/s Figure 6.13: IBM Ultrastar 36LZX geometry and performance. Source: www.storage.ibm.com
Disk manufacturers often neglect to publish detailed technical information about the geometry of the individual recording zones. However, storage researchers have developed a useful tool, called DIXtrac, that automatically discovers a wealth of low-level information about the geometry and performance of SCSI disks . For example, 6.1. STORAGE TECHNOLOGIES
DIXtrac is able to discover the detailed zone geometry of our example IBM disk, whi...
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