UNIVERSITY EXAMINATIONS: 2018/2019
EXAMINATION FOR THE DIPLOMA IN BUSINESS INFORMATION
TECHNOLOGY
DBIT403 COMPUTER OPERATING SYSTEMS
DATE: AUGUST, 2019 TIME: 2 HOURS
INSTRUCTIONS: Answer Question One and ANY other two questions.
QUESTION ONE [30 MARKS]
(a) Explain each of the following terms as used in operating systems:- [5 Marks]
(i) External fragmentation
(ii) Shell
(iii)Process scheduling
(iv)Deadlock
(v) Operating system
(b) Discuss four conditions necessary for a deadlock condition to occur [8 Marks]
(c) Explain three reasons for using a Graphical User Interface (GUI) rather than a Command
Line Interface (CLI) [6 Marks]
(d) Explain five key factors to consider while selecting a computer operating system[5
Marks]
(e) Outline four examples of commonly used operating systems in the market [4 Marks]
(f) Giving an example in each case, distinguish between the terms Application software &
system software as used in computer systems [2 Marks]
QUESTION TWO [20 MARKS]
(a) Explain four factors that determine the choice of a processor scheduling technique
[4 Marks]
(b) With the aid of a well labeled diagram, illustrate and briefly explain the five states of a
process as used in operating systems [7 Marks]
(c) With the aid of diagrams, describe each of the following memory management
techniques:-
(i) Swapping [3 Marks]
(ii) Segmentation [3 Marks]
(iii)Paging [3 Marks]
QUESTION THREE [20 MARKS]
(a) Define the term ‘semaphore” as used in operating systems [2 Marks]
(b) Discuss six key functions of a computer operating system [6 Marks]
(c) Describe the following process scheduling algorithms outlining the advantages and
disadvantages:-
(i) FIFO [4 Marks]
(ii) Priority scheduling [4 Marks]
(iii)Shortest Job First [4 Marks]
QUESTION FOUR [20 MARKS]
(a) Give MS-DOS commands to carry out each of the tasks:-
(i) Create a directory name Operating Systems in Drive C:\ [2 Marks]
(ii) Display all the directories in drive D:\ [2 Marks]
(iii)Display today’s date [2 Marks]
(iv)Rename a directory name Computers to Systems in drive D:\ [2 Marks]
(b) Explain the following terms as used in operating systems:-
(i) Disk formatting [2 Marks]
(ii) Disk compression [2 Marks]
(iii)Computer booting [2 Marks]
(c) List and explain the functions of three types of schedulers as used in operating systems
[6 Marks]
QUESTION FIVE [20 MARKS]
(a) State the purpose of swap file in memory management [2 Marks]
(b) Explain four advantages of NTFS systems over the FAT file system [4 Marks]
(c) With the aid od well labeled diagram, illustrate and explain the components of a Process
Control Block (PCB) as used in operating systems [6 Marks]
(d) List and explain three categories of operating systems [6 Marks]
(e) Outline two attributes of a computer file [2 Marks]
