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Cork Institute of Technology
Bachelor of Science in Computing – Award
(National Diploma in Computing – Award)
(NFQ – Level 7)
Autumn 2005
Systems Administration
(Time: 3 Hours)
Instructions Answer FOUR questions. All questions carry equal marks.
Examiners: Mr. G. MacSweeney Mr. E. A. Parslow Dr. D. Chambers Ms. K. O Dubhchair
Q1. (a) In the context of networking, what is a protocol? (2 Marks)
(b) What are the layers of the OSI model? (4 Marks)
(c) Distinguish between the upper and lower layers of the OSI model. (2 Marks)
(d) In the context of networking, what is meant by data encapsulation? (2 Marks)
(e) What is a Linux distribution? (1 Mark)
(f) Name two common Linux distributions. (2 Marks)
(g) On an Intel / PC platform what is the BIOS? (2 Marks)
(h) What is the purpose of a computer’s BIOS? (3 Marks)
(i) What are the main tasks of a systems administrator? (5 Marks)
(j) State two advantages of Unix. (2 Marks)
Q2. (a) The command (^) useradd can be used by an administrator to create a new user. How might the potential user be supplied with a password? Describe how the administrator might also provide the user with a home directory to store his/her files. Where might this home directory be placed? (7 Marks)
(b) Apart from using useradd , describe two other ways of creating a user account in a standard Linux distribution. (3 Marks)
(c) Explain how users are authenticated when they log in to a Linux system. In your answer consider password security. (5 Marks)
(d) What are the security risks of a user using a simple password. (2 Marks)
(e) Describe how file permissions work in a Unix / Linux environment. (8 Marks)
Q3. Describe – with the aid of appropriate diagrams - three methods of disk space allocation. In your answer, state the advantages and disadvantages of each. (12 Marks) (a) Describe with the aid of a diagram how Unix allocates disk space. (6 Marks)
(b) In the context of changing a file’s permissions, describe how the octal notation could be used to change the permission string. (3 Marks)
(c) Explain the difference between pre-emptive and non pre-emptive scheduling? (2 Marks) (d) State one example of a pre-emptive scheduling algorithm and one example of a non pre-emptive scheduling algorithm. (2 Marks)
- (a) Using an appropriate diagram, describe the five state model for process states and transititions. (10 marks)
(b) Explain the terms: seek time , latency time and transfer time. ( marks)
(c) For the following track request queue: 180 63 67 58 84 128 7 159 78 57 Write down the order in which the tracks are visited for each of the following scheduling algorithms:
I. Shortest Seek Time First II. Look Assume the tracks are numbered from 0 to 199 and that the head starts at track 61 and is moving towards 199. (5 marks) (d) What are the four principal requirements of a system security policy? (4 marks)
Q6. (a) In Linux, explain what is meant by a runlevel? (2 marks)
(b) For most systems what would you expect to be the default runlevel? (1 mark)
(c) How would you configure a system to change its default runlevel (i.e. the next time the system is booted up a different runlevel is running)? (3 marks) Consider the following part of the /etc/inittab file:
si::sysinit:/etc/rc.d/rc.sysinit
l0:0:wait:/etc/rc.d/rc 0 l1:1:wait:/etc/rc.d/rc 1 l2:2:wait:/etc/rc.d/rc 2 l3:3:wait:/etc/rc.d/rc 3 l4:4:wait:/etc/rc.d/rc 4
d) What is the purpose of the rc.sysinit file? (2 marks)
e) What is the function of the line l3:3:wait:/etc/rc.d/rc 3? (2 marks)
f) Suggest two reasons why an administrator might want to partition a hard disk. (4 marks) g) What is a link? Distinguish between the two different kinds of links. (5 marks) h) Describe what approaches an administrator might take to solve disk storage problems. (6 marks)
