NOS Exam paper (2000/2002)

1

(a)

Contrast the different methods that an operating system scheduler can undertake, and their main characteristics. Which is likely to give the smoothest scheduling, and which is likely to be the most efficient on processor time. Give reason(s) for your choice. Also which scheduling does Windows NT and UNIX use? (10)

(b)

Outline the usage of signals in UNIX and contrast the usage of signals in UNIX with messages in Microsoft Windows. What is the major problem with signals, and how might it be overcome?
(10)

2

(a)

Outline the main methods that are used in interprocess communications (IPC), and identify any major problems which occur with the methods.
(12)

(b)

Explain the two main methods that cause deadlock. Also, define the four main conditions that must occur for deadlock to happen. Finally, briefly outline how the Bankers Algorithm can be used to avoid deadlock.
(13)

3

(a)

Contrast distance-vector routing protocols with link-state routing protocols. What methods may a distance-vector protocol use to determine the best route?
(12)

(b)

(b) Define and explain the two major problems with distance-vector routing protocols, and the methods that can be used to overcome these problems.
(13)

4

(a)

Outline the main disadvantages with Novell NetWare 3.1, and how these have been overcome in Novell NetWare 4.1/NDS. Also, discuss the main enhanced features of Novell NetWare 4.1/NDS.
(13)

(b)

Explain how NDS uses a 32-bit time stamp to record the time of events. Also explain the different types of time servers that can be set up on a NetWare 4.1 network.
(12)

5

(a)

Explain how NFS creates a networked file system. Also, outline the main components of NFS and how they fit into the OSI model. (12)

(b)

Explain how NIS is used to create a network configuration, and the files that are used. How does this method improve network security and the operation of a network? Also explain the operation of primary and secondary NIS servers. Why is it important to have secondary NIS servers?
(13)

6

(a)

Explain typical methods that a networking operating system may use to create a robust networked data storage environment. Highlight, possibly with a basic example, the method that RAID 5 uses to protect data against a hard disk failure.
(13)

(b)

Contrast the security model for a FAT-based system, a UNIX-based system and a Windows NT system.
(12)