Fall 2001 CSCI 333 Homework 7

This assignment is due Friday, 9 November.

Problem 1

Consider a disk drive with the following characteristics.

• 10 GB total storage
• 10 surfaces
• 800 cylinders
• interleaving factor of one
• rotational speed of 7500 rpm
• track-to-track seek time of 15msec
• average seek time of 90 msec

The questions

Answer the following questions regarding the disk drive describe above.

1. How many 512 byte sectors are on this disk drive?
2. How many total tracks (on all cylinders) are on this disk drive?
3. How many sectors are stored on each single track?
4. How many sectors are stored on each cylinder?
5. How long, in msec, does it take this disk to rotate?
6. How many bytes can be read in one disk rotation?
7. What is the average rotation delay in reading from the disk?
8. What is the maximum data transfer rate from the disk?
9. What is the average time, in msec, required to read a random sector of data from the disk?
10. If a 100Mbyte file could be stored in consecutive sectors of the disk, how many cylinders and tracks would it require?
11. How long would it take to read this 100Mbyte file stored in consecutive sectors?
12. If this 100Mbyte file was stored in sectors randomly scattered throughout the disk and the file must be read sequentially, how long would it take to read the file?
13. If this 100Mbyte file that was randomly scattered throughout the disk could be read in any order, how long would it take to read the file? Consider reading the file by moving from one end of the disk to the other, reading data blocks as they are encountered in each cylinder.

Problem 2

Find URL's on the Internet that discuss the following topics.

1. MS/DOS FAT
2. Unix inodes
3. Log-based file systems
4. Performance data for a state-of-art disk drive
5. Disk drives prices
6. Handling of dirty pages or buffers
7. Recommendations for virtual memory allocations in a Windows-based operating system
8. Arguments that can be supplied to the open and seekg methods in C++'s fstream class
9. Error correction methods used in disk drives
10. Linux ext3 journaling file system

Turning in this assignment

Email your answers to the instructor. If you wish, you many also turn in written material that flows how you performed the calculations required in Question 1.