Exam May 2016, questions PDF

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Examination question paper: May 2017 Module code: CS5001 Component number: 004 Module title: Networks and Operating Systems Module leader: Dr. Peiyuan Pan Date: 31 May 2017 Start time: 10:00 Duration: 2 Hours Exam type: Unseen, Closed Materials supplied: None Materials permitted: None Warning: Candi...

Description

Examination question paper: May 2017 Module code:

CS5001

Component number:

004

Module title:

Networks and Operating Systems

Module leader:

Dr. Peiyuan Pan

Date:

31 May 2017

Start time:

10:00

Duration:

2 Hours

Exam type:

Unseen, Closed

Materials supplied:

None

Materials permitted:

None

Warning:

Candidates are warned that possession of unauthorised materials in an examination is a serious assessment offence.

Instructions to candidates:

Candidates should answer Section A, and plus ANY THREE out of the FOUR Questions in Section B.

You are NOT allowed to take the question paper out of the examinatiom/test room. Question papers will be collected by the invigilator at the end of the exam/test.

Do not turn page over until instructed © London Metropolitan University

Page 1 of 6

Section A (40 marks in total, 2 marks each) For each question in this section, there are four possible answers, indicated by i), ii), iii), or iv). You need to give your answer in your answer book in the format like 22) i), which means you have chosen option i) for question 22 as the correct answer. For certain questions, more than one option may appear to be correct. In such cases, choose the best option. 1)

Which of the following are types of Twisted Pair Cable? i) Coaxial cable ii) Shielded Twisted Pair (STP) iii) Unshielded Twisted Pair (UTP) iv) Only ii) and iii)

2)

HUB is a _____ device and Switch is a _________ device i) Unicast, Multicast ii) Broadcast, Unicast iii) Malticast, Unicast iv) None of above

3)

Which of the following are examples of radiated media? i) Radio ii) Microwave iii) satellite iv) All of above

4)

Star topology is based on a central device that can be _____? i) HUB ii) Switch iii) Router iv) Both i) and ii)

5)

Which one is NOT key parameter of transmission waves: i) Amplitude ii) Wave length iii) Frequency iv) i) & iii)

6)

For frequency modulation, by convention, which of the following represents 0? i) 2100HZ ii) 1300HZ iii) 1100HZ iv) None of them

7)

Which of the following topology has to use absorbers to eliminate signals on the channel? i) Ring ii) BUS iii) Star iv) None of them

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8)

Which of the following has a signal communication channel that is shared by all the users on the network? i) Point-to-Point ii) Broadcast network iii) Protocal iv) Private Area Network

9)

Which of the following is the advantage when use fiber optics for data transmission? i) Higher bandwidth ii) Resistance to data theft iii) Low noise level iv) All of above

10)

Why was the OSI model developed? i) Manufacturers disliked the TCP/IP protocol ii) The rate of data transfer was increased exponentially iii) Standards were needed to allow any two systems to communicate iv) No reasons for the development

11)

Which one is correct for transmission signals? i) Signals are electromagnetic waveforms ii) Signals move close to the speed of light iii) i) and ii) iv) None of above

12)

Communication services can support i) Electronic funds transfer ii) Electronic mail iii) Videoconferencing iv) More than the above

13)

Operating system manages i) Memory ii) Processor iii) I/O devices iv) All of above

14)

In which type of the following OS, response time is very crucial i) Networking operating system ii) Real time operating system iii) Batch operating system iv) UNIX operating system

Page 3 of 6

15)

Which of the following is correct description when a program is in execution? i) Under compiling ii) File management iii) A process iv) Processor control

16)

Which of the following are the disadvantages of single-user systems? i) No support for multiprogramming or networking ii) Not cost effective iii) Program size must be less than memory size to execute iv) All of the above

17)

UNIX operating system is an i) Multi user operating system ii) Time sharing operating system iii) Multi tasking operating system iv) All of above

18)

Most operating systems provide a set of system calls, which invoke low level OS functions. Which of the following is a feature of system calls? i) The use of system calls is direct to the user ii) The use of system calls is not direct, hidden from the user iii) Systems calls are not hidden from the user iv) None of the above

19)

A program in execution is called i) A paging ii) A control unit iii) A process iv) An application

20)

User interface is the users’ gateway into the computer, enabling the required humancomputer interaction to take place. It ultimately requires i) software link to the hardware even if such link is buried beneath other layers of software ii) the user to decide how to link to hardware iii) i) and ii) iv) none of above

-----END

of Section A-----

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Section B ----- Answer ANY THREE Questions in this Section ----Question 1 (20 marks in total) a) Briefly describe what conducted media is, and what is radiated media? [8 marks] b) Briefly define bandwidth. What is the unit of measurement for bandwidth? An analogue communications channel CH is capable of transmitting signals in the range from 200 Hz to 3200 Hz. Calculate the bandwidth of the communications channel CH. [7 marks] c) Shannon’s equation to calculate the maximum amount of data that can be transmitted per second: S = B log2 (1 + (W/N)). S is Transmission Speed (Bits/second), B is bandwidth (Hertz), W is power of signal (Watts) and N is noise on the line (Watts). Assume W/N = 255 and B = 3100, what is the transmission speed? (Please note that 27 is 128.) [5 marks]

Question 2 (20 marks in total) Sketch the Open Systems Interconnection (OSI) Reference Model and describe the services provided by each layer. [20 Marks]

Question 3 (20 marks in total) An interrupt is a signal which can cause the operating system to suspend its current activity and deal with the new situation. Please answer the following questions: a) What types of interrupt resources exist?

[10 marks]

b) The simplest view of processor action is that it consists of a simple fetch-execute cycle. If an interrupt mechanism is incorporated into the cycle, i.e., after each instruction terminates, the processor checks for the occurrence of an interrupt. Please describe how the process cycle will be affected in order to provide the service to the interrupt, and draw a diagram to illustrate [10 marks]

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Question 4 (20 marks in total) a) In the operating system, a process control block (PCB) is used for storing the information about the processes. You are required to list at least five pieces of such information stored in PCB used by the processor at the run time. [10 marks] b) The following is a process state diagram (the three state model) showing how the states are transitioned and some process state details at conception level. You are required to describe your understanding such as [10 marks] i) which scheduler controls which transition, and ii) which steps it follows from one state to the other (In the figure below, HLS: High Level Scheduler, and LLS: Low Level Scheduler)

I/O COMPLETION HLS

BLOCKED

READY

PROCESS ENTRY

DISPATCH (LLS)

TIMEOUT

I/O WAIT RUNNING TERMINATION

Process State Diagram (The Three State Model)

END OF THE PAPER

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