UNIVERSITI MALAYSIA SARAWAK KOTA SAMARAHAN SARAWAK ITC2053 OPERATING SYSTEM

Transcription

1 STUDENT IDENTIFICATION NO UNIVERSITI MALAYSIA SARAWAK KOTA SAMARAHAN SARAWAK FAKULTI SAINS KOMPUTER & TEKNOLOGI MAKLUMAT (Faculty of Computer Science & Information Technology) Diploma in Multimedia Technology FIRST, EIGHT SEMESTER FINAL EXAMINATION, 2013/2014 SESSION ITC2053 OPERATING SYSTEM DMTQ-E-F-1/11, DSEW-E-F-2/13 20 FEBRUARY PM 4.00 PM (2 HOURS) INSTRUCTION TO STUDENT 1. This Examination paper has FOURTEEN (14) printed pages. 2. This question paper consists of THREE (3) sections. Section A : Answer ALL questions Section B : Answer ALL questions Section C : Answer SIX (6) questions ONLY. 3. Please write all your answers in the Answer Booklet provided.

2 SECTION A : OBJECTIVE QUESTIONS (20 MARKS) INSTRUCTION : ANSWER ALL QUESTIONS 1. means that several logical records are grouped within one physical record. A. Grouping B. Fixing C. Combining D. Blocking 2. A(n) in the busy list occurs when a memory block between two other busy memory blocks is returned to the free list. A. blank line B. null entry C. joined entry D. empty entry 3. There are entries per page in the PMT. A. 0 B. 1 C. 2 D A page size that is too small will generate. A. very long PMTs B. excessive internal fragmentation C. more difficult to calculate actual position D. excessive external fragmentation MFAH Page 2 of 14

3 5. When selecting the proper time quantum it should be long enough to allow percent of the CPU cycles to run to completion. A. 20 B. 60 C. 80 D Internal interrupts, or interrupts, also occur as a direct result of the arithmetic operation or job instruction currently being processed. A. I/O B. illegal job instruction C. illegal operation D. synchronous 7. A of processing must be handled as a unit. A. line B. Segment C. critical region D. semaphore 8. Operations on semaphore s enforce the concept of, which is necessary to avoid having two operations attempt to execute at the same time. A. mutual execution B. mutex execution C. signal exclusion D. mutual exclusion MFAH Page 3 of 14

4 9. A thread transitions from RUNNING to when it has to wait for an event outside its control to occur. A. LOOPING B. BLOCKED C. WAITING D. PENDING 10. The number of characters that can be recorded per inch on a magnetic tape is determined by the of the tape. A. Width B. Length C. Density D. parity 11. It takes 2.5 minutes to reach the last record on a tape, is the average access time. A. 5 minutes B. 1 minute C minutes D. 2 minutes 12. To write data to flash memory, an electric charge is sent through one transistor, called the, then through a metal oxide layer, and into a second transistor called the control gate where the charge is stored in a cell until it s erased. A. parallel port B. floating gate C. pit D. crystalline port MFAH Page 4 of 14

5 13. Without DMA, the is responsible for the physical movement of data between main memory and the device. A. CPU B. Bus C. memory controller D. disk 14. The most commonly used access control scheme is the. A. access control matrix B. access control list C. capability list D. capability matrix 15. is a popular option for still images and for video images A. ANSI, MPEG B. ISO, CGI. C. JPEG, VPEG D. JPEG, MPEG 16. The file function causes the DO/S File Manager to use a master directory with information about all files stored anywhere on the system and set up a channel to the file. A. Find and Open B. Read C. Write D. Create MFAH Page 5 of 14

6 17. Trash collection, also known as, is an evening pastime for those who enjoy perusing anything and everything thrown out by system users. A. dumpster diving B. Recycling C. dumpster surfing D. trash surfing 18. Using, a firewall reviews the header information for incoming and outgoing Internet packets to verify that the source address, destination address, and protocol are all correct. A. Snooping B. packet filtering C. a proxy server D. anti-virus software 19. A server hides important network information from outsiders by making the network server invisible. A. Redirection B. Blocking C. Proxy D. fire MFAH Page 6 of 14

7 20. Assume that a system consisting of CPU 1 and Disk Drive A (access speed 35 ms) has to access Track 1, Track 9, Track 1, and then Track 9, and that the arm is already located at Track 1. Without reordering, Drive A requires to complete the access. A. 30 ms B. 35 ms C. 70 ms D. 105 ms MFAH Page 7 of 14

8 SECTION B : TRUE (T) OR FALSE (F) (20 MARKS) INSTRUCTION : ANSWER ALL QUESTIONS 1. Until the mid-1970s, all computers were classified by price alone. 2. Since the mid-1970s rapid advances in computer technology have blurred the distinguishing characteristics of early machines. 3. Research continues to focus on finding the optimum allocation scheme. 4. To move in a new page, a resident page must be swapped back into primary storage. 5. A process is an inactive unit, such as a file stored on a disk. 6. Each job is uniquely identified by the user s identification and a pointer connecting it to its descriptor. 7. It is easy to design a foolproof deadlock prevention policy. 8. In parallel computations, mutual exclusion is achieved automatically because each operation is handled in order, one at a time. 9. The problem of masters and slaves arises when two types of processes need to access a shared resource such as a file or database. 10. When using DMA, the CPU is involved in transferring data to and from memory for the entire transfer. MFAH Page 8 of 14

9 11. The SCAN algorithm moves the arm methodically from the inner to the outer track, servicing every request in its path. 12. In a file management system, information is passed from the Device Manager at the top of the hierarchy to the File Manager at the bottom. 13. Data in a fixed-length field might include a short name followed by many blank characters; it can be replaced with a variable-length field and a special code to indicate how many blanks were truncated. 14. The network operating system handles the interfacing details and coordinates the remote processing. 15. Each kernel is operated by the application software which, in turn, is directed by the kernel running on the host computer. 16. A single computer without access to or the Internet is easy to protect and has a low risk of attack. 17. Wire tapping is when unauthorized users gain the capability to search through storage, directories, or files for information they aren t privileged to read. 18. A continuing series of security awareness and ethics communications to computer users is more effective than a single announcement. 19. The performance of each system resource is independent of any other resource. 20. Any system improvement can be made only after extensive analysis of the needs of the system s resources, requirements, managers, and users. MFAH Page 9 of 14

10 SECTION C : LONG QUESTIONS (60 MARKS) INSTRUCTION : ANSWER SIX (6) QUESTIONS ONLY. Question 1 Name FIVE (5) current operating systems and the computers or configurations each operates. (10 Marks) Question 2 Explain the fundamental differences between internal fragmentation and external fragmentation. For each of the four memory management systems (single user, fixed, dynamic, and relocatable dynamic), identify which one causes each type of fragmentation. (10 Marks) Question 3 a) Compare and contrast internal fragmentation and external fragmentation. Explain the circumstances where one might be preferred over the other. (3 Marks) b) Describe how the function of the Page Map Table (PMT) differs in paged versus segmented/demand paging memory allocation. (3 Marks) MFAH Page 10 of 14

11 c) Using a paged memory allocation system with a page size of 2,048 bytes and an identical page frame size, and assuming the incoming data file is 25,600 bytes, calculate how many pages will be created by the file. Calculate the size of any resulting fragmentation. Explain whether this situation will result in internal fragmentation, external fragmentation, or both. (4 Marks) Question 4 a) Describe context switching in lay terms and identify the process information that needs to be saved, changed, or updated when context switching takes place? (3 Marks) b) Five jobs (A, B, C, D, E) are already in the READY queue waiting to be processed. Their estimated CPU cycles are respectively: 2, 10, 15, 6, and 8. Using SJN, in what order should they be processed? (3 Marks) c) A job running in a system, with variable time quantums per queue, needs 30 milliseconds to run to completion. If the first queue has a time quantum of 5 milliseconds and each queue thereafter has a time quantum that is twice as large as the previous one, how many times will the job be interrupted and on which queue will it finish its execution? (4 Marks) MFAH Page 11 of 14

12 Question 5 Give one real life examples (not related to a computer system environment) of each of these concepts: deadlock, starvation, and race. Question 6 (10 Marks) a) Compare the processors access to printers and other I/O devices for the master/slave and the symmetric multiprocessing configurations. Give a real-life example where the master/slave configuration might be preferred. b) Compare the processors access to main memory for the loosely coupled configuration and the symmetric multiprocessing configurations. Give a real-life example where the symmetric configuration might be preferred. Question 7 a) Describe how primary storage differs from secondary storage. b) Explain the differences between buffering and blocking. MFAH Page 12 of 14

13 Question 8 a) Is device independence important to the File Manager? Why or why not. Describe the consequences if that were not the case. b) Do you think file retrieval is different on a menu-driven system and a commanddriven system? Explain your answer and describe any differences between the two. Give an example when each user interface would be preferred over the other. Question 9 a) Explain the role of routers when moving data from one host to another in the same network. (2 Marks) b) This chapter described packet routing. Explain the two ways in which packets can be routed and how they differ. (4 Marks) c) Give two real-life examples where packet switching would be preferred over circuit switching and explain why. (4 Marks) MFAH Page 13 of 14

14 Question 10 a) List three benefits of data redundancy as described in this chapter. (6 Marks) b) Describe in detail how a DO/S protects a file from access or modification by an unauthorized user. Compare it to NOS file protection. (4 Marks) Question 11 a) Give three examples of excellent passwords and explain why each would be a good choice to protect a system from unauthorized users. b) Give three advantages and disadvantages of password generator software. Would you recommend the use of such software for your own system? Explain why or why not. End of Page. MFAH Page 14 of 14