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Cork Institute of Technology
Higher Certificate in Science in Computing in Information
Technology Support – Stage 1
(NFQ Level 6)
Autumn 2007
Operating Systems
(Time: 2 Hours)
InstructionsAnswer FOUR questions. All questions are worth equal marks.
Examiners: Mr. G. McSweeneyMr. J. Greenslade Mr. J. Walsh
1. a) Apart from Microsoft Windows, name two other well known operating systems. ( 2 Marks ) b) What are the two principal functions of an operating system? ( 4 Marks ) c) Describe in detail the three main types of memory in a computer system. Rank them in terms of their speed and capacity. ( 8 Marks ) d) What is the purpose of a device driver? ( 2 Marks ) e) What is the purpose of a compiler? ( 2 Marks ) f) What is a GUI? ( 2 Marks ) g) Name a popular Linux GUI ( 2 Marks ) h) What is a bootstrap loader? ( 3 Marks )
a) Explain the difference between a pre-emptive and a non pre-emptive scheduling algorithm. ( 2 Marks ) Consider the following set of processes with duration given in milliseconds. Arrival Service P1 0 2 P2 2 4 P3 4 1 P4 5 3 b) Draw a time line to show the execution of each of these processes for the Robin scheduling algorithm (time slice = 2). Calculate the Turnaround Time Round (i.e. the waiting time plus the service time) for each process. ( 8 Marks )
c) Draw the five state transition diagram. In your answer include both the states and thetransitions. ( 10 Marks )
d) What are suspended states? ( 3 Marks ) e) Name two suspended states. ( 2 Marks )
a) Name four services a typical server might offer its clients. ( 4 Marks ) b) In a client-server relationship, what is the usual minimum service a client might offer its user? ( 2 Marks ) c) What additional applications might you expect to be on a typical client? ( 4 Marks ) d) Describe the differences between the following algorithms and suggest an example of where each might be appropriate: i. One-way encryption algorithm ii. Single key encryption algorithm iii. Public key encryption algorithm ( 9 Marks ) e) What are the main features of a computer virus? ( 2 Marks ) Melissa and ILOVEYOU were two viruses distributed by email in 1999 and 2000 respectively. f) (^) short period of time.Describe how these viruses managed to infect millions of computers worldwide in a ( 4 Marks )
6. a) State some of the advantages of using UNIX. ( 5 Marks ) b) What are the file permissions used in UNIX? ( 6 Marks ) c) What is a Linux distribution? ( 2 Marks ) d) Give an example of a Linux distribution? ( 2 Marks ) The following is an example of a listed file. -rw-r--r-- 1 smithj group4 28 Oct 2 11:43 tempFile
e) Explain the meaning of each of the items. ( 6 Marks ) f) Name two different types of UNIX files? ( 2 Marks ) g) What type of file is the above listing? ( 2 Marks )
