x=17

Assignment \#4 5 Bonus Marks 1. Consider a disk with a sector size of 1024 bytes, 500 tracks per surface, 100 sectors per track, 6 single-sided platters and a block size of 4096 bytes. Suppose that a file containing 1,000,000 records of 200 bytes each is to be stored on such a disk and that no record is allowed to span two blocks. a) How many records fit onto a block? b) How many blocks are required to store the entire file? If the file is arranged sequentially (contiguously-according to the 'next block concept') on disk, how many cylinders are needed? c) How many records of 200 bytes each can be stored using this disk? 2. Consider an 4-drive, 1000GB-per-drive RAID array. What is the available data storage capacity for each of the RAID levels 0,1,3,4,5, and 6 ? 3. Design a backup strategy for a computer system. One option is to use plug-in external disks, which cost SAR 150 for each 500 GB drive. Another option is to buy a tape drive for SAR 5000 , and 400GB tapes for SAR 50 apiece. A typical backup strategy is to have two sets of backup media onsite, with backups alternately written on them so in case the system fails while making a backup, the previous version is still intact. There's also a third set kept offsite, with the offsite set periodically swapped with an on-site set. a. Assume you have [x]TB(1TB=1000GB) of data to back up. How much would a disk backup system cost? b. How much would a tape backup system cost for [x] TB? c. How large would each backup have to be in order for a tape strategy to be less expensive? d. What kind of backup strategy favors tapes? Note: For x: Use last two digits of your student number. In case if last two digits are zero then use the fourth \& third last digits. Important: Show stepwise calculations for all parts. Highlight your answers. Failure to comply with instruction will result in marks deduction