Unit 4

I/O SYSTEMS

Mass Storage Structure- Overview, Disk Scheduling and Management; File System Storage-File Concepts, Directory and Disk Structure, Sharing and Protection; File System Implementation- File System Structure, Directory Structure, Allocation Methods, Free Space Management; I/O Systems.

Part A

# Question
1 Compare the various file access methods .
2 How does DMA increase system concurrency?
3 Illustrate the techniques used to protect the user files
4 If the average page faults service time of 25 ms and a memory access time of 100ns.Calculate the effective access time.
5 List the responsibility of the file manager
6 Identify the two important functions of virtual file system(VFS) layer in the concept of file system implementation.
7 Do FAT file system is advantageous? Why?
8 Illustrate the pros and cons of a fixed head disk and a moving head disk.
9 Define rotational latency.
10 Define UFD and MFD.
11 Give the disadvantages of Contiguous allocation
12 Formulate any four common file types. Write the various file attributes.
13 Name the two types of system directories?
14 Summarize the characteristics that determine the disk access speed?
15 Mention the objectives of file management system.
16 What is the need for disk scheduling? Give the various disk scheduling methods.
17 Why is rotational latency usually not considered in disk scheduling?
18 Adisk has 26310 cylinders,16 tracks and 63 sectors. The disk spins at 7200 rpm.Seek time between adjacent track is 1 ms.How long does it take to read the entire disk?
19 Formulate any three disadvantages of placing functionality in a device controller, rather than in the kernel .
20 Give the importance of swap space management

Part B

# Question
1 Assume the head of a moving disk with 200 tracks, numbered 0....199, is currently serving a request at track 92, and has just finished a request at track 85 and the queue request is kept in the FIFO order, 109, 148, 89, 72, 126, 142. What is the total headmovementneededtosatisfytheserequestsforthe SCAN,C-SCAN,LOOKandC-LOOKdiskscheduling algorithms? (13)
2 D escribe in detail about file sharing and protection.(13)
3 (i)Explain about the RAID structure in disk management with various RAID levels of organization in detail (9) (ii) Briefly discuss about the various directory structure (4)
4 (i)Describe with a neat sketch about the various directory structure (7) (ii)Describe in detail about free space management with neat examples. (6)
5 Distinguish between the different file access methods.(13)
6 (i)Give in detail about application-I/O interface (7) (ii)Explain the services provided by kernel I/O subsystems (6)
7 Illustrate how the free space list is implemented with neat diagram and define what is free space management .(13)
8 Classify the different file allocation methods with neat diagram. Mention the advantages and disadvantages.(13)
9 Analyse the common schemes available for defining the logical structure of a directory.(13)
10 (i)Describe how the disk space from deleted files can be reused (7) (ii)Describe the life cycle of I/O request in detail (6)
11 Describe the functions of files and file implementation.(13)
12 (i)Compare the functionalities of FIFO, SSTF, C-SCAN, and C-LOOK disk scheduling algorithms with an example for each (7) (ii)Explain the issues in designing a file systems.(6)
13 Examine in detail about Directory and disk structure.(13)
14 (i)Describe how file system is implemented in WindowsXP(7) (ii) Describe how file system is implemented in Linux (6)