Hard Disk capacity calculations
1) Suppose you have a hard disk with 1600 tracks per surface, each track divided into 64 sectors, eight platters and a blocksize of 512 bytes (i.e., 1⁄2 kilobyte),
what is the total raw capacity of the disk drive?
2) Once installed in a computer and made ready for use to hold files, the OS reports that a disk has 186 GB of available space. Yet, you know the drive has a raw
capacity of slightly more than 200 GB. Where did the 14 GB go?
3) On a linux system with disk blocks of 1 KB and 32-bit block numbers, how many disk seeks are needed to read each of the following block numbers: 7, 49, 392, 67,
72491, 3122 ?
4) Suppose you need to add more disk capacity to a system. You consider a SLED: a 6 TB single dr ive for $220. What’s the cost-per-byte of this dr ive? You also have
access to 10 1 TB dr ives at $45 each. What’s the cost-per-bye of one of these disks? If you make a RAID 5 box out of the 1 TB dr ives, why do you choose to use seven
disks in order to have the full 6 TB capacity the SLED provides? What’s one important feature the RAID 5 ‘dive’ provides that the SLED cannot?
