![]() Capacity of 28-bit LBA = 2 28 Sectors = 128GB * Newest hard disk use 48-bit ~ 1 Million times bigger! Limitation of Logical Block Addressing (LBA) * Most hard disk use 28-bit LBA addressing. Logical Block Addressing (LBA) Suppose a Hard disk with CHS= 2040 / 16 / 63 To access a sector on Cyl: 2000, Head: 10, Sect: 60 (CHS= 2000 / 10 / 60 ) LBA value = 2000 x 16 x 63 + 10 x 63 + 60 = 2016690 Sect 1 Sect 63 Head 0 Head 1 Sect 126 Head 15 Sect 1008 Cyl. 3 3 Modify BIOS’s design For addressing still using traditional CHS values Logical Block Addressing (LBA) LINEAR addressing instead of using CHS values Newer OS/file system e.g. Convert the physical values to logical values, e.g. To Overcome the Limitations Address Translation Controller board on hard disk translates the the CHS values such that the no. Limitations of Your System * The disk capacity limited by the min. A hard disk with 1023 Cylinders, 6 Heads and 63 Sectors/Track (CHS=3) Capacity = 1023 x 6 x 63 x 512 Bytes = 386694 sectors = 197987328 B = 188.8 MB Side/Head Track Sector ![]() ![]() Physical Geometry About Your Disk Side(Head) Cylinder (Tracks per Side) Track Sectors/Track Cluster 1 Sector = 512 Bytes Capacity = Cylinder x Head x Sector x 512 Bytes e.g. Knowing your Hard Disk and Partition Management Managing Your Hard Disk and Operating System 23,26 March 2004 2:30pm - 4:00pm ![]()
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