Section A : Basic Concepts (30 Marks)
1. A “data mart” is
(a) A shop where we get the data we want
(b) A small data warehouse designed for a department or a strategic business unit
(c) A hardware used for data base
(d) A section in the wall mart
(e) Data on markets.
2. ‘Meta data’ is
(a) A collection of data on metals (b) A huge data base (c) Data about data
(d) A method to retrieve data (e) Irrelevant data.
3. GIS stands for
(a) Geological Indian Survey
(b) Graphical Interactive System
(c) Graphical Information System
(d) Geological Information Society
(e) Geographic Information System.
4. Following are some of the Heuristic (developing rules to solve a complex problem) algorithms, except one:
(a) Construction heuristics
(b) Improvement heuristics
(c) Mathematical programming
(d) Random Number generation (e) Decomposition.
5. Except for one, the following are some of the advantages of “Simulation” method in Decision Support Systems.
(a) A great amount of time compression can be attained
(b) It is descriptive rather than normative, helping the user to pose ‘what-if’ question
(c) It automatically produces many important performance measures
(d) It can generally handle an extremely wide variety of problem types
(e) It is built for one particular problem and typically cannot handle any other problem.
6. In developing a DSS or MIS, the process of developing a “quick version” of a system, for the end user, is known as
(a) Prototyping (b) Photographing (c) Profiling (d) Performing (e) Promoting.
7. And user developed Decision Support System (DSS) has the following advantages except for one.
(a) The system delivery time is short
(b) The prerequisites of extensive and formal user requirements specifications are eliminated
(c) Lack of DSS design knowledge and controls, can result in poor quality
(d) Some DSS implementation problem are reduced
(e) The development cost is usually low.
8. Even though it can cripple an organization, sometimes people refuse to share what they know (knowledge). Except for one, the following are some reasons why people don’t share knowledge. Find the odd one out.
(a) People believe that knowledge is power and that hoarding it guarantees job security
(b) People won’t get credit for sharing knowledge
(c) People don’t have time to share knowledge
(d) People believe that giving away the information they have will result in the reduction in their bank account balance
(e) People are afraid of making mistakes and looking bad or being reprimanded.
9. Which of the following is not a reason as to why organisations implement Knowledge Management System?
(a) Better decision making (b) Reduced costs (c) Statutory obligation
(d) Faster response time to key issues (e) Improved productivity.
10. Which of the following is not a step/stage in a decision making process?
(a) Problem identification (b) Generation of alternatives (c) Choice
(d) Implementation (e) Salary.
11. The process of knowledge discovery / information harvesting using a database is known as
(a) Data description (b) Data encryption (c) Data mining (d) Data coding
(e) Data encoding.
12. Decision taken, that is not based on any rule or method, and is novel and non-recurrent in nature is
(a) Programmed decision (b) Non-programmed decision (c) Semi-programmed decision
(d) Set decision (e) Irrelevant decision.
13. Which of the following system caters to the operational needs of the finance department of an organization?
(a) Human Resource Information System
(b) Marketing Information System
(c) Executive Information System
(d) Finance & Accounts System
(e) Production Planning & Control System.
14. In a decision making process, where the decision maker considers situation in which several outcomes are possible for each course of action, comes under _______ type of decision making.
(a) Certianity (b) Risk (c) Uncertianity (d) Sure (e) No-risk.
15. Which of the following is a limitation of Decision Support Systems?
(a) Extend the decision maker’s ability to process information and knowledge
(b) Extend the decision maker’s ability to tackle large-scale, time consuming, complex problem
(c) Shorten the time associated with a decision making
(d) Cannot yet be designed to contain definitely human decision making talents such as creativity, imagination or intuition
(e) Improve the reliability of a decision process or outcome.
16. Which of the following is not a force acting upon a typical decision maker?
(a) Personal and Emotional (b) Gravitation (Earth’s) (c) Economic (Environmental) (d) Organisational (e) Contextual and Emergence.
17. Find the odd one out
(a) SAP (b) BAAN (c) Oracle Financial (d) People Soft (e) Oracle 10g.
18. Which of the following is not a major issue that need to be addressed in the evaluation and selection of an ERP software package?
(a) Cost and ROI benefits (b) Implementation time and support (c) Programming language
(d) Service support (e) Functionality fit.
19. Even when two individuals take a similar decision, their decision making style need not be the same. The manner in which individuals organize and manipulates data is known as
(a) Life style (b) Cognitive style (c) Hyper style (d) Hypo style (e) Hair style.
20. An effective MIS should have the following features, except
(a) Ability to provide information that will reduce uncertainity
(b) Building a knowledge base
(c) Reducing errors using high level validation techniques
(d) Building strong public relation with outsiders
(e) Ensuring that MIS is designed in such a way the information cannot be misused.
21. Sales Force automation will come under
(a) Finance & Accounting System
(b) Marketing Information System
(c) Manufacturing Information System
(d) Human Resource Information System
(e) Production Planning & Control System.
22. Management information system mainly deals with:
(a) Hardware (b) Software (c) Network (d) Information (e) Cables.
23. Internet-like networks between a company and its business partners is called
(a) Intranet (b) Extranet (c) Protocol (d) Internetworks (e) Fishnet.
24. If an organization has been collecting data regarding production units per shift then they should not shift to production units per day. This is an example of:
(a) Validity (b) Reliability (c) Consistency (d) Impartiality (e) Complexity.
25. Group method for eliciting a wide variety of suggestions by open flow of ideas can be termed as
(a) Guided brainstorming (b) Group consensus (c) Brainstorming (d) Open discussion
(e) Restricted discussion.
26. Which of the following enables workers at different locations to create a shared electronic environment and use IT to design the structure of the organization?
(a) Systemware (b) Shareware (c) Middleware (d) Groupware (e) Designerware.
27. Which of the following organizations have no structure?
(a) Virtual organizations
(b) Traditional organizations with electronic components
(c) Negotiated agreement organizations
(d) Electronic conglomerates
(e) Multinational companies.
28. The point at which the new system replaces the old system is called
(a) Flag point (b) Termination point (c) Milestone (d) Cutover (e) Shutdown.
29. Computers in manufacturing concerns are largely used for ______________
(a) Market intelligence (b) Advertising (c) Pay roll (d) Production and inventory control
(e) Public Relations.
30. The immediate step after MIS implementation is
(a) Feasibility study (b) Evaluation (c) Preparation of the project status report
(d) Documentation of the implementation process (e) Draw the data flow diagram.
Section B : Caselets (50 Marks)
Caselet 1
Read the caselet carefully and answer the following questions:
1. What business problems were solved at Visa-Pro India by linking call centers and product databases? (6 marks)
2. What business benefits does Visa-Pro India expect from this approach? (7 marks)
Visa-Pro India expected its call center agents to answer customer queries quickly, completely, and politely. But as the systems that the agents used couldn’t find al the answers a customer was sometimes transferred to several operators before all his questions were answered.
In 1995, Visa-Pro India increased the training for its call center agents enabling them to have more information on a range of products to reduce the number of call transfers. But it didn’t work. To increase customer satisfaction, Visa-pro India is changing its approach. It is using a software that links its eight call centers and a variety of product databases so an agent can answer questions without transferring the call and soon, agents will be able to interact with customers via email and the Internet. Visa-Pro India recently chose a Customer Communications Solution software and is rolling it out to a total of 800 agents in eight call centers across India. Once the system is in place, a customer will be able to call one agent about any of Visa-Pro India’s 8 credit-card and other financial products.
Instead of transferring a customer to a different operator for each product, the new software will give each agent access to eight different product databases. The new approach will help Visa-Pro save Rs.30 million annually on its call center budget.
3. “Merely designing an EIS does not ensure its success.” What are the various barriers that prevent the effectiveness of an EIS? (12 marks)
Caselet 2
Read the caselet carefully and answer the following questions:
4. Why was the implementation process an easy one for South India Shipping corporation Ltd.?
(6 marks)
5. What are the advantages of implementing financial software? (7 marks)
Companies generally purchase software and then customize it to meet their customer’s needs. But sometimes a company may have to change its business processes to conform to a software package. In line with a company-wide decree to move from mainframes to client/server computing, South India Shipping Corporation Ltd acquired R/3 financial software modules from Germany’s SAP AG. South India Shipping corporation Ltd is one of the world’s leading global container transportation companies. It has 100 offices in about 40 countries. The shipping major owns and charters about 34 container vessels deployed in 30 liner services carrying more than 1 million containers worldwide every year. SAP met the shipping company’s requirements for handling its international customers. With this software, customers can choose a particular currency for payment, the country in which they want to pay the bill, and identify the party that will pay-the shipper or the consignee. Adapting the shipper’s existing processes to suit the standard accounting modules of SAP was easy because the company wanted to make changes to these processes. The accounting function also reduced the number of employees from 100 to 70 with the help of process reengineering. The different part of the global implementation of the R/3 financial modules was not the roll out but the design phase that preceded it. During the design phase, the company invited representatives from its offices in various countries and continents to participate. South India Shipping corporation Ltd. also hired project consultants and used the consultancy’s project management methodology to document the design process. The implementation of the R/3 financial modules was started in Chicago. Then the company operated on country and module by module as it rolled out R/3 financials across its overseas offices.
6. The president of Abhilash Industries could not understand why his manager was unable to take a rational decision in a crisis. His manager explained the problem. What can be the problem according to the manager? (12 marks)
Section C : Applied Theory (20 Marks)
7. List the benefits and limitations of a Decision Support System. (10 marks)
8. How do information systems support the activities of manages in an organization? (10 marks)
Suggested Answers
1.
Answer : (b)
Reason : A “data mart” is a small data warehouse designed for a department or a strategic business unit.
2.
Answer : (c)
Reason : ‘Meta data’ is data about data.
3.
Answer : (e)
Reason : GIS stands for Geographic Information System.
4.
Answer : (d)
Reason : Random Number generation is not a Heuristic algorithm.
5.
Answer : (e)
Reason : “Simulation” has a limitation in the fact that it can be built for one particular problem and normally cannot handle any other. All other options given, are its advantages.
6.
Answer : (a)
Reason : In developing a DSS or MIS, the process of developing a “quick version” of a system, for the end user, is known as Prototyping.
7.
Answer : (c)
Reason : Lack of DSS design knowledge and controls, can result in poor quality, and hence this is a limitation, where as all others are its advantages.
8.
Answer : (d)
Reason : People believe that giving away the information they have will result in the reduction in their bank account balance is the odd one out, as all others are valid reasons for not sharing information.
9.
Answer : (c)
Reason : Statutory obligation is not a reason as to why companies implement knowledge management system.
10.
Answer : (e)
Reason : Salary is not a step/stage in a decision making process.
11.
Answer : (c)
Reason : The process of knowledge discovery / information harvesting using a database is known as data mining.
12.
Answer : (b)
Reason : Non-programmed decision are decisions taken that is not based on any rule or method and is novel and non-recurrent in nature.
13.
Answer : (d)
Reason : Finance & Accounts System caters to the operational needs of the Finance department of an organization.
14.
Answer : (c)
Reason : In a decision making process, where the decision maker considers situation in which several outcomes are possible for each course of action, comes under “Uncertianity type of decision making.
15.
Answer : (d)
Reason : The limitation of Decision Support Systems is that it cannot yet be designed to contain definetly human decision making talents such as creativity, imagination or intuition.
16.
Answer : (b)
Reason : Gravitation (Earth’s) is not a force acting upon a typical decision maker.
17.
Answer : (e)
Reason : Oracle 10g is a RDBMS package. All others are ERP softwares.
18.
Answer : (c)
Reason : Programming language is not a major issue that need to be addressed in the evaluation and selection of an ERP software package.
19.
Answer : (b)
Reason : The manner in which individuals organize and manipulates data is known as Cognitive style.
20.
Answer : (d)
Reason : Building strong public relation with outsiders is not a feature of MIS.
21.
Answer : (b)
Reason : Sales Force automation will come under Marketing Information System.
22.
Answer : (d)
Reason : Management information system mainly deals with Information.
23.
Answer : (b)
Reason : Internet-like networks between a company and its business partners is called Extranet. 24.
Answer : (c)
Reason : If an organization has been collecting data regarding production units per shift then they should not shift to production units per day. This is an example of Consistency.
25.
Answer : (c)
Reason : Group method for eliciting a wide variety of suggestions by open flow of ideas can be termed as Brainstorming.
26.
Answer : (d)
Reason : Groupware enables workers at different locations to create a shared electronic environment and use IT to design the structure of the organization.
27.
Answer : (a)
Reason : Virtual organizations have no structure.
28.
Answer : (d)
Reason : The point at which the new system replaces the old system is called Cutover.
29.
Answer : (d)
Reason : Computers in manufacturing concerns are largely used for Production and inventory control.
30.
Answer : (b)
Reason : The immediate step after MIS implementation is Evaluation.
Tuesday, November 25, 2008
Management Information Systems (MC261) – July 2006
Thursday, November 20, 2008
Operating Systems (MC251) : January 2008
Section A : Basic Concepts (30 Marks)
1. Which of the following is the single user and single task operating system?
(a) Windows NT (b) Unix (c) PC Dos (d) Windows 2000 (e) H line MTS.
2. Which of the following is not one of the User Services provided by the operating system?
(a) Program Execution (b) I/O Operations (c) Accounting (d) File Manipulation (e) Error Detection.
3. A job requires 10 seconds of execution time, and let’s assume the time quantum is 3 seconds. Into how many phases the job is executed?
(a) 0 (b) 1 (c) 2 (d) 3 (e) 4.
4. Which system call is used to run a new program in the process?
(a) Load (b) Execv (c) Fork (d) Request Device (e) Exit.
5. What is the portion of the operating system that must remain in memory at all times called?
(a) Instructions (b) Heap (c) BIOS (d) Monitor (e) Kernel.
6. Which of the following allows different parts of a single program to run concurrently?
(a) Multi programming (b) Multi Processing (c) Multi user (d) Multi threading
(e) Multi tasking.
7. Which problem is considered as a classic synchronization problem?
(a) Reader writers (b) Bound buffer (c) Dining philosopher (d) Producers consumer (e) All of the above.
8. Which among the following is not the minimal set of instructions that must be protected?
(a) Change to monitor mode
(b) Read from monitor memory
(c) Write into monitor memory
(d) Turn off timer interrupt
(e) Change to user mode.
9. Process is otherwise known as
I. Task.
II. Job.
III. Program.
(a) Only (I) above
(b) Only (II) above
(c) Both (I) and (II) above
(d) Both (II) and (III) above
(e) Both (I) and (III) above.
10. Which of the following becomes an important characteristic in the RR scheduling?
(a) CPU burst time (b) Time Quantum (c) Priority (d) Number of Processors (e) Number of Jobs.
11. What does FAT stand for?
(a) Fixed Allocation Table
(b) Fat Allocation Table
(c) File Allocation Table
(d) File Allocation Terminator
(e) File Arranged Table.
12. Which program swaps out the active process from the ready queue?
(a) PCB (b) Dispatcher (c) Device driver (d) Monitor (e) I/O device.
13. Which factor tells the amount of time a process has been waiting in the ready queue?
(a) Turnaround time (b) Waiting time (c) Response time (d) Throughput
(e) CPU utilization.
14. In a paging scheme the physical memory will be divided into
(a) Pages (b) Frames (c) Blocks (d) Cells (e) Segments.
15. The place where OS programs stored in the main memory is called
(a) User memory area (b) Monitor memory area (c) Heap area (d)Stack area (e) Data area.
16. Moving a program disk to main memory is called
(a) Swap In (b) Swap Out (c) Relocation (d) Paging (e) Enter In.
17. The wastage of memory in a fixed partition is called
(a) External Fragmentation (b) Internal Fragmentation (c) Complete Memory Wastage (d) Job Pool (e) Segmentation.
18. The technique of combining several small tiny holes into a big hole is called
(a) Paging (b) Aging (c) Compaction (d) Starvation (e) Reduction.
19. --------Memory management scheme transfers the required pages into main memory, but not entire program.
(a) Paging (b) Segmentation (c) Demand paging (d) Thrashing (e) Segmentation with paging.
20. If the required page is not present in the main memory, then it is called
(a) Page break (b) Page default (c) Frame fault (d) Page finish (e) Page fault.
21. Resource allocation graph is used for
(a) Detecting the deadlock
(b) Preventing the deadlock
(c) Recovering from the deadlock
(d) To cause a dead lock
(e) All of the above.
22. Which of the following symbol is used to represent the resource vertex in a RAG?
(a) (b) (c) (d) (e)
23. Which of the following causes the deadlock in the system?
(a) Process (b) Hold &Wait (c) No-Preemption (d) Pre-emption (e) Both (b) and (c) above.
24. If a process is made to wait for a long time without starting execution in the ready queue, then it is called
(a) Deadlock (b) Halted (c) Starvation (d) Both (a) and (c) above
(e) Both (a) and (b) above.
25. The technique used to avoid the starvation in the system is called
(a) Paging (b) Removing (c) Aging (d) Compaction (e) Segmentation.
26. Once a process has been given a CPU, the CPU cannot be taken away from that process until it completes the execution. This technique is called
(a) Pre-emption (b) Non pre-emption (c) Real-time (d) Response time (e) Blocking.
27. The Round Robin CPU scheduling algorithm uses
(a) FIFO circular queue (b) FIFO linear queue (c) FIFO linked queue
(d) LIFO circular queue (e) FILO circular queue.
28. Which CPU scheduling algorithm is used in Windows NT operating system
(a) Pre-emptive Priority (b) SJF (c) Round Robin (d) FCFS (e) Pre-emptive SJF.
29. ______ Algorithm is used to verify whether the system state results safe or unsafe
(a) Safety (b) Bankers (c) Test (d) Check (e) Find.
30. Which is the advantage of segmentation?
(a) Supports user view of main memory
(b) Eliminates fragmentation
(c) Provide large virtual memory
(d) Allows dynamic segment growth
(e) All of the above.
Section B : Problems (50 Marks) 1.
Suppose that the following processes arrive for execution at the times indicated. Each process will run the listed amount of time. In answering the questions, use nonpreemptive scheduling and base all decisions on the information you have at the time the decision must be made.
Process
Arrival Time
Burst Time
P1
0.0
8
P2
0.4
4
P3
1.0
1
a. What is the average turnaround time for these processes with the FCFS scheduling algorithm? ( 3 marks)
b. What is the average turnaround time for these processes with the SJF scheduling algorithm?
( 3 marks)
c. The SJF algorithm is supposed to improve performance, but notice that we chose to run process P1 at time 0 because we did not know that two shorter processes would arrive soon. Compute what the average turnaround time will be if the CPU is left idle for the first 1 unit and then SJF scheduling is used. Remember that processes P1 and P2 are waiting during this idle time, so their waiting time may increase. This algorithm could be known as future-knowledge scheduling. ( 4 marks)
2. List five services provided by an operating system. Explain how each provides convenience to the users. Explain also in which cases it would be impossible for user-level programs to provide these services. ( 10 marks)
3. Suppose you type the following in a UNIX command window:
rm xyz (This is a request for the operating system to delete the file xyz.)
Describe the actions the operating takes to complete this command. Discuss this at the level of process creation, memory management, searching for files, PCB’s, ready queues, and blocked queues. ( 10 marks)
4. Consider a file system on a disk that has both logical and physical block sizes of 512 bytes. Assume that the information about each file is already in memory. For each of the three allocation strategies (contiguous, linked, and indexed), answer these questions: a. How is the logical-to-physical address mapping accomplished in this system? (For the indexed allocation, assume that a file is always less than 512 blocks long.) ( 5 marks)
b. If we are currently at logical block 10 (the last block accessed was block 10) and want to access logical block 4, how many physical blocks must be read from the disk? ( 5 marks)
5.
a. Is disk scheduling, other than FCFS scheduling, useful in a single-user environment? Explain.
( 5 marks)
b. Consider a logical address space of 16 pages of 4096 words each, mapped onto a physical memory of 128 frames.
i. How many bits are there in the logical address?
ii. How many bits are there in the physical address? ( 5 marks) Section C : Applied Theory ( =SUM(D3:D50) 20 Marks)
6. Define the essential properties of the following types of operating systems:
a. Batch.
b. Interactive.
c. Time sharing.
d. Real time.
e. Distributed. ( 10 marks)
7.
a. Fragmentation on a storage device could be eliminated by recompaction of the information. Typical disk devices do not have relocation or base registers (such as are used when memory is to be compacted), so how can we relocate files? Give three reasons why recompacting and relocation of files often are avoided. ( 5 marks)
b. What is the cause of thrashing? How does the system detect thrashing? Once it detects thrashing, what can the system do to eliminate this problem? ( 5 marks)
Suggested Answers
1.
C
PC Dos is the single user and single task operating system.
2.
C
Accounting falls into the category of System Services.
3.
E
The job is executed in 4 phases.The order is 3 3 3 1.therefore the number of phases are 4.
4.
B
Execv system call is used to run a new program in the process.
5.
E
Kernel is the portion of the operating system that must remain in memory at all times
6.
D
Multithreading allows different parts of single program to run concurrently.
7.
C
Dining philosopher problem is considered as classic Synchronization problem.
8.
E
Change to user mode is not the minimal set of instructions that must be protected.
9.
c
10.
C
11.
C
FAT stands for File Allocation Table. It is an important variation of linked allocation method.
12.
B
Dispatcher program swaps out the active process from the ready queue.
13.
B
Waiting time tells the amount of time a process has been waiting in the ready queue.
14.
B
In a paging scheme the physical memory will be divided into Frames
15.
B
The place where O.S programs stored in the main memory is called monitor area.
16.
A
Moving a program disk to main memory is called Swap In
17.
B
The wastage of memory in a fixed partition is called Internal Fragmentation.
18.
C
The technique of combining of several small tiny holes into a big hole is called Compaction
19.
C
Demand Paging Memory management scheme transfers the required pages into main memory, but not entire program
20.
E
If the required page is not present in the main memory, then it is called Page fault
21.
A
Resource allocation graph is used for Detecting the Dead lock
22.
A
Rectangle represents resource vertex
23.
E
Hold and wait and no preemption causes deadlock.
24.
C
If a process is made to wait for a long time with out starting execution in the ready queue, then it is called -------
25.
C
Aging is the technique used to avoid the satarvation.
26.
B
Non Preemption is Once a process has been given a CPU, the CPU cannot be taken away from that process until it completes the execution
27.
A
The Round Robin CPU scheduling algorithm uses FIFO Circular Queue
28.
A
CPU scheduling algorithm is used in Windows NT operating system is Pre-emptive Priority
29.
A
Reason:Safety Algorithm is used to verify whether the system state results safe or unsafe.
30.
E
the advantages of segmentation are:
i. Supports user view of main memory.
ii. Eliminates fragmentation.
iii. Provide large virtual memory.
iv. Allows dynamic segment growth.
v. Facilitates shared segments.
1. Which of the following is the single user and single task operating system?
(a) Windows NT (b) Unix (c) PC Dos (d) Windows 2000 (e) H line MTS.
2. Which of the following is not one of the User Services provided by the operating system?
(a) Program Execution (b) I/O Operations (c) Accounting (d) File Manipulation (e) Error Detection.
3. A job requires 10 seconds of execution time, and let’s assume the time quantum is 3 seconds. Into how many phases the job is executed?
(a) 0 (b) 1 (c) 2 (d) 3 (e) 4.
4. Which system call is used to run a new program in the process?
(a) Load (b) Execv (c) Fork (d) Request Device (e) Exit.
5. What is the portion of the operating system that must remain in memory at all times called?
(a) Instructions (b) Heap (c) BIOS (d) Monitor (e) Kernel.
6. Which of the following allows different parts of a single program to run concurrently?
(a) Multi programming (b) Multi Processing (c) Multi user (d) Multi threading
(e) Multi tasking.
7. Which problem is considered as a classic synchronization problem?
(a) Reader writers (b) Bound buffer (c) Dining philosopher (d) Producers consumer (e) All of the above.
8. Which among the following is not the minimal set of instructions that must be protected?
(a) Change to monitor mode
(b) Read from monitor memory
(c) Write into monitor memory
(d) Turn off timer interrupt
(e) Change to user mode.
9. Process is otherwise known as
I. Task.
II. Job.
III. Program.
(a) Only (I) above
(b) Only (II) above
(c) Both (I) and (II) above
(d) Both (II) and (III) above
(e) Both (I) and (III) above.
10. Which of the following becomes an important characteristic in the RR scheduling?
(a) CPU burst time (b) Time Quantum (c) Priority (d) Number of Processors (e) Number of Jobs.
11. What does FAT stand for?
(a) Fixed Allocation Table
(b) Fat Allocation Table
(c) File Allocation Table
(d) File Allocation Terminator
(e) File Arranged Table.
12. Which program swaps out the active process from the ready queue?
(a) PCB (b) Dispatcher (c) Device driver (d) Monitor (e) I/O device.
13. Which factor tells the amount of time a process has been waiting in the ready queue?
(a) Turnaround time (b) Waiting time (c) Response time (d) Throughput
(e) CPU utilization.
14. In a paging scheme the physical memory will be divided into
(a) Pages (b) Frames (c) Blocks (d) Cells (e) Segments.
15. The place where OS programs stored in the main memory is called
(a) User memory area (b) Monitor memory area (c) Heap area (d)Stack area (e) Data area.
16. Moving a program disk to main memory is called
(a) Swap In (b) Swap Out (c) Relocation (d) Paging (e) Enter In.
17. The wastage of memory in a fixed partition is called
(a) External Fragmentation (b) Internal Fragmentation (c) Complete Memory Wastage (d) Job Pool (e) Segmentation.
18. The technique of combining several small tiny holes into a big hole is called
(a) Paging (b) Aging (c) Compaction (d) Starvation (e) Reduction.
19. --------Memory management scheme transfers the required pages into main memory, but not entire program.
(a) Paging (b) Segmentation (c) Demand paging (d) Thrashing (e) Segmentation with paging.
20. If the required page is not present in the main memory, then it is called
(a) Page break (b) Page default (c) Frame fault (d) Page finish (e) Page fault.
21. Resource allocation graph is used for
(a) Detecting the deadlock
(b) Preventing the deadlock
(c) Recovering from the deadlock
(d) To cause a dead lock
(e) All of the above.
22. Which of the following symbol is used to represent the resource vertex in a RAG?
(a) (b) (c) (d) (e)
23. Which of the following causes the deadlock in the system?
(a) Process (b) Hold &Wait (c) No-Preemption (d) Pre-emption (e) Both (b) and (c) above.
24. If a process is made to wait for a long time without starting execution in the ready queue, then it is called
(a) Deadlock (b) Halted (c) Starvation (d) Both (a) and (c) above
(e) Both (a) and (b) above.
25. The technique used to avoid the starvation in the system is called
(a) Paging (b) Removing (c) Aging (d) Compaction (e) Segmentation.
26. Once a process has been given a CPU, the CPU cannot be taken away from that process until it completes the execution. This technique is called
(a) Pre-emption (b) Non pre-emption (c) Real-time (d) Response time (e) Blocking.
27. The Round Robin CPU scheduling algorithm uses
(a) FIFO circular queue (b) FIFO linear queue (c) FIFO linked queue
(d) LIFO circular queue (e) FILO circular queue.
28. Which CPU scheduling algorithm is used in Windows NT operating system
(a) Pre-emptive Priority (b) SJF (c) Round Robin (d) FCFS (e) Pre-emptive SJF.
29. ______ Algorithm is used to verify whether the system state results safe or unsafe
(a) Safety (b) Bankers (c) Test (d) Check (e) Find.
30. Which is the advantage of segmentation?
(a) Supports user view of main memory
(b) Eliminates fragmentation
(c) Provide large virtual memory
(d) Allows dynamic segment growth
(e) All of the above.
Section B : Problems (50 Marks) 1.
Suppose that the following processes arrive for execution at the times indicated. Each process will run the listed amount of time. In answering the questions, use nonpreemptive scheduling and base all decisions on the information you have at the time the decision must be made.
Process
Arrival Time
Burst Time
P1
0.0
8
P2
0.4
4
P3
1.0
1
a. What is the average turnaround time for these processes with the FCFS scheduling algorithm? ( 3 marks)
b. What is the average turnaround time for these processes with the SJF scheduling algorithm?
( 3 marks)
c. The SJF algorithm is supposed to improve performance, but notice that we chose to run process P1 at time 0 because we did not know that two shorter processes would arrive soon. Compute what the average turnaround time will be if the CPU is left idle for the first 1 unit and then SJF scheduling is used. Remember that processes P1 and P2 are waiting during this idle time, so their waiting time may increase. This algorithm could be known as future-knowledge scheduling. ( 4 marks)
2. List five services provided by an operating system. Explain how each provides convenience to the users. Explain also in which cases it would be impossible for user-level programs to provide these services. ( 10 marks)
3. Suppose you type the following in a UNIX command window:
rm xyz (This is a request for the operating system to delete the file xyz.)
Describe the actions the operating takes to complete this command. Discuss this at the level of process creation, memory management, searching for files, PCB’s, ready queues, and blocked queues. ( 10 marks)
4. Consider a file system on a disk that has both logical and physical block sizes of 512 bytes. Assume that the information about each file is already in memory. For each of the three allocation strategies (contiguous, linked, and indexed), answer these questions: a. How is the logical-to-physical address mapping accomplished in this system? (For the indexed allocation, assume that a file is always less than 512 blocks long.) ( 5 marks)
b. If we are currently at logical block 10 (the last block accessed was block 10) and want to access logical block 4, how many physical blocks must be read from the disk? ( 5 marks)
5.
a. Is disk scheduling, other than FCFS scheduling, useful in a single-user environment? Explain.
( 5 marks)
b. Consider a logical address space of 16 pages of 4096 words each, mapped onto a physical memory of 128 frames.
i. How many bits are there in the logical address?
ii. How many bits are there in the physical address? ( 5 marks) Section C : Applied Theory ( =SUM(D3:D50) 20 Marks)
6. Define the essential properties of the following types of operating systems:
a. Batch.
b. Interactive.
c. Time sharing.
d. Real time.
e. Distributed. ( 10 marks)
7.
a. Fragmentation on a storage device could be eliminated by recompaction of the information. Typical disk devices do not have relocation or base registers (such as are used when memory is to be compacted), so how can we relocate files? Give three reasons why recompacting and relocation of files often are avoided. ( 5 marks)
b. What is the cause of thrashing? How does the system detect thrashing? Once it detects thrashing, what can the system do to eliminate this problem? ( 5 marks)
Suggested Answers
1.
C
PC Dos is the single user and single task operating system.
2.
C
Accounting falls into the category of System Services.
3.
E
The job is executed in 4 phases.The order is 3 3 3 1.therefore the number of phases are 4.
4.
B
Execv system call is used to run a new program in the process.
5.
E
Kernel is the portion of the operating system that must remain in memory at all times
6.
D
Multithreading allows different parts of single program to run concurrently.
7.
C
Dining philosopher problem is considered as classic Synchronization problem.
8.
E
Change to user mode is not the minimal set of instructions that must be protected.
9.
c
10.
C
11.
C
FAT stands for File Allocation Table. It is an important variation of linked allocation method.
12.
B
Dispatcher program swaps out the active process from the ready queue.
13.
B
Waiting time tells the amount of time a process has been waiting in the ready queue.
14.
B
In a paging scheme the physical memory will be divided into Frames
15.
B
The place where O.S programs stored in the main memory is called monitor area.
16.
A
Moving a program disk to main memory is called Swap In
17.
B
The wastage of memory in a fixed partition is called Internal Fragmentation.
18.
C
The technique of combining of several small tiny holes into a big hole is called Compaction
19.
C
Demand Paging Memory management scheme transfers the required pages into main memory, but not entire program
20.
E
If the required page is not present in the main memory, then it is called Page fault
21.
A
Resource allocation graph is used for Detecting the Dead lock
22.
A
Rectangle represents resource vertex
23.
E
Hold and wait and no preemption causes deadlock.
24.
C
If a process is made to wait for a long time with out starting execution in the ready queue, then it is called -------
25.
C
Aging is the technique used to avoid the satarvation.
26.
B
Non Preemption is Once a process has been given a CPU, the CPU cannot be taken away from that process until it completes the execution
27.
A
The Round Robin CPU scheduling algorithm uses FIFO Circular Queue
28.
A
CPU scheduling algorithm is used in Windows NT operating system is Pre-emptive Priority
29.
A
Reason:Safety Algorithm is used to verify whether the system state results safe or unsafe.
30.
E
the advantages of segmentation are:
i. Supports user view of main memory.
ii. Eliminates fragmentation.
iii. Provide large virtual memory.
iv. Allows dynamic segment growth.
v. Facilitates shared segments.
Operating Systems (MC251) : July 2007
Section A : Basic Concepts (30 Marks)
1. Which of the following controls the access of programs, processes or users to the resources defined by the system?
(a) Prevention (b) Security (c) Protection (d) Access stop (e) Access right.
2. A distributed system is a collection of processors that
(a) Do not share memory (b) Has no memory (c) Share memory
(d) Has less memory (e) Has more memory.
3. Which of the following is true related to the CPU utilization?
I. Throughput should be less.
II. Response time should be less.
III. Waiting time should be less.
IV. Turnaround time should be less.
(a) Only (I) above
(b) Both (I) and (II) above
(c) Both (I) and (IV) above
(d) Both (II) and (III) above
(e) Both (III) and (IV) above.
4. Which of the following must be satisfied by a Critical Section?
I. Progress.
II. Mutual Exclusion.
III.Bounded Waiting.
(a) Only (I) above
(b) Only (II) above
(c) Only (III) above
(d) Both (I) and (II) above
(e) All (I), (II) and (III) above.
5. ACL stands for
(a) Attribute Control List
(b) Access Connection List
(c) Access Control Line
(d) Access Connection Line
(e) Access Control List.
6. The following diagram identifies:
(a) Directory graph (b) Tree structured directory (c) Acyclic graph directory
(d) General graph directory (e) Cyclic graph directory.
7. Identify the synonym for physical formatting.
(a) Logical Formatting (b) Low Level Formatting (c) High Level Formatting
(d) Medium Level Formatting (e) Reformatting.
8. When a CPU scheduling algorithm determines an order for the execution of its scheduled processes. Given n processes to be scheduled on one processor. What is the number of possible different schedules?
(a) n (b) n+1 (c) n-1 (d) n! (e) n*n.
9. The two valid semaphore operations are
(a) Signal and die (b) Wait and signal (c) Wait and interrupt
(d) Wait and terminate (e) Wait and die.
10. Access-right is equal to
(a) (b) (c) (d) (e)
11. Which of the following graph describes the deadlocks more precisely?
(a) Pie graph (b) Bar graph (c) Gantt graph (d) Resource Allocation graph (e) XY graph.
12.PTLR stands for
(a) Page Table Load Register
(b) Page Tree Length Register
(c) Program Table Length Register
(d) Page Table Length Ready
(e) Page Table Length Register.
13. Which of the following is a non-self modifying code?
I. Machine code.
II. Critical section code.
III. Reentrant code.
IV. Pure code.
(a) Only (I) above
(b) Only (II) above
(c) Only (III) above
(d) Only (IV) above
(e) Both (III) and (IV) above.
14. specifies:
I. Pi requests instance of Rj.
II. Pi releases instance of Rj.
III. Pi holds instance of Rj.
(a) Only (I) above
(b) Only (II) above
(c) Only (III) above
(d) Both (I) and (II) above
(e) All (I), (II) and (III) above.
15. What is the formula for Effective Access Time?
(a) EAT= (1-p) + ma*p+pft
(b) EAT= (1+p) * ma+p*pft
(c) EAT= (1*p) * ma+p*pft
(d) EAT= (1-p) * ma+p*pft
(e) EAT= (1/p) + ma+p*pft.
16. Which of the following specifies (1, 0) in enhanced second chance algorithm?
(a) Referred and modified
(b) Modified and not Referred
(c) Referred but not modified
(d) Neither referred nor modified
(e) Meaning less.
17. Identify the synonym for Direct Access
(a) Sequential Access (b) Indexed Access (c) Relative Access (d) Linked Access
(e) Multilevel Access.
18. What is the portion of the operating system that must remain in memory at all times?
(a) Kernel (b) Bios (c) Monitor (d) Stack (e) Instructions.
19. What is the process of moving a process' code and data around in main memory without having to recompile?
(a) Deallocation (b) Reallocation (c) Compilation (d) Exécution (e) Interprétation.
20. The figure below illustrates
(a) SCAN (b) SSTF (c) C-SCAN (d) C-LOOK (e) LOOK.
21. Consider that a process arrives into the system at time 20 and needs 50 time units in the CPU. Because of other processes, it doesn’t start to execute until time 130, and doesn’t complete till time 300, then how long is its waiting time?
(a) 220 (b) 230 (c) 240 (d) 250 (e) 260.
22. A process P consists of five pages P1, P2, P3, P4, and P5, but the operating system allows only THREE page-frames. During its lifetime the process references its pages in the order P1, P2, P3, P2, P1, P4, P1, and P5. If the memory management policy is LFU (Least Frequently Used, with FIFO used to decide ties), which page will be replaced to make room for P5?
(a) P1 (b) P2 (c) P3 (d) P4 (e) P5.
23. What is the effective access time for a page default with a probability of 40%, page fault service time of 8 milliseconds and a memory access time of 200 nanoseconds?
(a) 248.1 nanoseconds (b) 200.3 nanoseconds (c) 128.4 nanoseconds
(d) 123.2 nanoseconds (e) 124.3 nanoseconds.
24. Which of the following operations of files allows the user to erase the content of a file keeping its attributes?
(a) Repositioning within the file (b) Truncating file (c) Deleting a file
(d) Renaming a file (e) Exiting from a file.
25. Which of the following is/are the technique(s) used for counting based page replacement?
I. Least Frequently Used (lfu).
II. Most Frequently Used (MFU).
III. Least Recently Used (LRU).
(a) Only (I) above
(b) Only (II) above
(c) Only (III) above
(d) Both (I) and (II) above
(e) All (I), (II) and (III) above.
26. Which of the following is the disc scheduling algorithm that selects the request with the minimum seek time from the current head position?
(a) FCFS Scheduling (b) SSTF Scheduling (c) SCAN Scheduling (d) LOOK Scheduling (e) C-LOOK Scheduling.
27. Which of the following is not a file attribute?
(a) Name (b) Protection (c) Security (d) Size (e) Location.
28. Which of the following is not a System Threat?
(a) WORM (b) Denial of Services (c) Internet WORM (d) Viruses (e) Trojan Horse.
29. A small piece of code used to locate the appropriate memory-resident library routine is called
(a) Skeleton (b) Server (c) Client (d) Stub (e) Program.
30. In which of the following one server runs the application or applications while other servers are standby?
(a) Asymmetric clustering (b) Symmetric Clustering (c) Fragmentation (d) Clustering
(e) Waited Computing.
Section B : Problems (50 Marks)
1
a. Explain the concept of transaction atomicity.
b. Is it possible to have a deadlock involving only one single process? Explain. (5 + 5 = 10 marks)
2 Consider a system that supports 5000 users. Suppose that you want to allow 4990 of these users to be able to access one file.
a. How would you specify this protection scheme in UNIX?
b. Could you suggest another protection scheme that can be used more effectively for this purpose than the scheme provided by UNIX? (4 + 6 = 10 marks)
3 Consider a file currently consisting of 100 blocks. Assume that the file control block and the index block, in the case of indexed allocation is already in memory. Calculate how many disk I/O operations are required for contiguous, linked, and indexed- single level allocation strategies, if, for one block, the following conditions hold. In the contiguous-allocation case, assume that there is no room to grow in the beginning, but there is room to grow in the end. Assume that the block information to be added is stored in memory.
a. The block is added at the beginning.
b. The block is added in the middle.
c. The block is added at the end.
d. The block is removed from the beginning.
e. The block is removed from the end. (5 * 2 = 10 marks)
4
a. Mention the main differences between capability lists and access lists.
b. What are the three major activities of an operating system in regard to secondary-storage management?
c. Explain the differences, in terms of cost, among the three storage types volatile, nonvolatile, and stable. (3 + 3 + 4 = 10 marks)
5
a. What is PCB? Identify the information associated with a specific process.
b. Name the five major categories of system calls to give examples. (5 + 5 = 10 marks)
Section C : Applied Theory (20 Marks)
6 What is IPC? Explain the different ways to implement IPC. (10 marks)
7 Differentiate between the following terms
a. Long Time Scheduler and Short Time Scheduler
b. Preemptive Scheduling and Non-preemptive Scheduling
c. Process and Program
d. Multilevel Queue and Multilevel Feedback Queue
e. MS DOS and Windows Operating systems. (2 + 2 + 2 + 2 +2 = 10 marks)
Suggested Answers
1.
Answer : (e)
Reason : Access right controls the access of programs, processes or users to the resources defined by the system.
2.
Answer : (a)
Reason : A distributed system is a collection of processors that do not share memory.
3.
Answer : (a)
Reason : Throughput should be less related to the CPU utilization is true.
4.
Answer : (e)
Reason : Critical Section will have Progress, Mutual Exclusion and Bounded Waiting
5.
Answer : (e)
Reason : ACL stands for: Access Control List.
6.
Answer : (d)
Reason : It is general graph directory
7.
Answer : (b)
Reason : Physical Formatting is also Called as Low Level Formatting
8.
Answer : (d)
Reason : Given n processes to be scheduled on one processor. The numbers of possible different schedules are n!.
9.
Answer : (b)
Reason : The two valid semaphore operations are wait () and signal ().
10.
Answer : (a)
Reason : Access-right =
11.
Answer : (d)
Reason : The deadlocks more precisely described by RAG.
12.
Answer : (e)
Reason : PTLR stands for Page table length register
13.
Answer : (e)
Reason : Reentrant or pure code is non self modifying code.
14.
Answer : (a)
Reason : Pi requests instance of Rj.
15.
Answer : (d)
Reason : The formula for Effective access time is (1-p) * ma+p*pft
16.
Answer : (c)
Reason : (1, 0) in enhanced second chance algorithm specifies Referred but not modified.
17.
Answer : (c)
Reason : The synonym for Direct Access is Relative Access.
18.
Answer : (c)
Reason : The portion of the operating system that must remain in memory at all times called kernel.
19.
Answer : (b)
Reason : Reallocation is the process of moving a process' code and data around in main memory without having to recompile.
20.
Answer : (c)
Reason : The figure illustrates C-SCAN.
21.
Answer : (b)
Reason : Consider that a process arrives in to the system at time 20, and needs 50 time units in the CPU. Because of other processes, it doesn’t start to execute until time 130, and doesn’t complete till time 300, then its waiting time is 230.
22.
Answer : (d)
Reason : A process P consists of five pages P1, P2, P3, P4, and P5, but the operating system allows only THREE page-frames. During its lifetime the process references its pages in the order P1, P2, P3, P2, P1, P4, P1, and P5. If the memory management policy is LFU (Least Frequently Used, with FIFO used to decide ties), then P4 page will be replaced to make room for P5.
23.
Answer : (d)
Reason : The formula for effective access time =
= (1 –P) ma + P x Page fault time
= (1-.4) 200 + .4 x 8
= 123.2 nanoseconds
24.
Answer : (b)
Reason : Rather than forcing the user to delete the file and then recreate truncating, it allows all attributes remain unchanged
25.
Answer : (d)
Reason : The techniques used for counting based page replacement are Least frequently used (lfu) and Most frequently used (MFU).
26.
Answer : (a)
Reason : The disc scheduling selects the request with the minimum seek time from the current head position is FCFS Scheduling
27.
Answer : (c)
Reason : Security is not a file attribute.
28.
Answer : (e)
Reason : Trojan Horse is not a System Threat.
29.
Answer : (d)
Reason : small piece of code, stub is used to locate the appropriate memory-resident library routine.
30.
Answer : (a)
Reason : Consider that one server runs the application or applications while other servers are standby called Asymmetric clustering
1. Which of the following controls the access of programs, processes or users to the resources defined by the system?
(a) Prevention (b) Security (c) Protection (d) Access stop (e) Access right.
2. A distributed system is a collection of processors that
(a) Do not share memory (b) Has no memory (c) Share memory
(d) Has less memory (e) Has more memory.
3. Which of the following is true related to the CPU utilization?
I. Throughput should be less.
II. Response time should be less.
III. Waiting time should be less.
IV. Turnaround time should be less.
(a) Only (I) above
(b) Both (I) and (II) above
(c) Both (I) and (IV) above
(d) Both (II) and (III) above
(e) Both (III) and (IV) above.
4. Which of the following must be satisfied by a Critical Section?
I. Progress.
II. Mutual Exclusion.
III.Bounded Waiting.
(a) Only (I) above
(b) Only (II) above
(c) Only (III) above
(d) Both (I) and (II) above
(e) All (I), (II) and (III) above.
5. ACL stands for
(a) Attribute Control List
(b) Access Connection List
(c) Access Control Line
(d) Access Connection Line
(e) Access Control List.
6. The following diagram identifies:
(a) Directory graph (b) Tree structured directory (c) Acyclic graph directory
(d) General graph directory (e) Cyclic graph directory.
7. Identify the synonym for physical formatting.
(a) Logical Formatting (b) Low Level Formatting (c) High Level Formatting
(d) Medium Level Formatting (e) Reformatting.
8. When a CPU scheduling algorithm determines an order for the execution of its scheduled processes. Given n processes to be scheduled on one processor. What is the number of possible different schedules?
(a) n (b) n+1 (c) n-1 (d) n! (e) n*n.
9. The two valid semaphore operations are
(a) Signal and die (b) Wait and signal (c) Wait and interrupt
(d) Wait and terminate (e) Wait and die.
10. Access-right is equal to
(a) (b) (c) (d) (e)
(a) Pie graph (b) Bar graph (c) Gantt graph (d) Resource Allocation graph (e) XY graph.
12.PTLR stands for
(a) Page Table Load Register
(b) Page Tree Length Register
(c) Program Table Length Register
(d) Page Table Length Ready
(e) Page Table Length Register.
13. Which of the following is a non-self modifying code?
I. Machine code.
II. Critical section code.
III. Reentrant code.
IV. Pure code.
(a) Only (I) above
(b) Only (II) above
(c) Only (III) above
(d) Only (IV) above
(e) Both (III) and (IV) above.
14. specifies:
I. Pi requests instance of Rj.
II. Pi releases instance of Rj.
III. Pi holds instance of Rj.
(a) Only (I) above
(b) Only (II) above
(c) Only (III) above
(d) Both (I) and (II) above
(e) All (I), (II) and (III) above.
15. What is the formula for Effective Access Time?
(a) EAT= (1-p) + ma*p+pft
(b) EAT= (1+p) * ma+p*pft
(c) EAT= (1*p) * ma+p*pft
(d) EAT= (1-p) * ma+p*pft
(e) EAT= (1/p) + ma+p*pft.
16. Which of the following specifies (1, 0) in enhanced second chance algorithm?
(a) Referred and modified
(b) Modified and not Referred
(c) Referred but not modified
(d) Neither referred nor modified
(e) Meaning less.
17. Identify the synonym for Direct Access
(a) Sequential Access (b) Indexed Access (c) Relative Access (d) Linked Access
(e) Multilevel Access.
18. What is the portion of the operating system that must remain in memory at all times?
(a) Kernel (b) Bios (c) Monitor (d) Stack (e) Instructions.
19. What is the process of moving a process' code and data around in main memory without having to recompile?
(a) Deallocation (b) Reallocation (c) Compilation (d) Exécution (e) Interprétation.
20. The figure below illustrates
(a) SCAN (b) SSTF (c) C-SCAN (d) C-LOOK (e) LOOK.
21. Consider that a process arrives into the system at time 20 and needs 50 time units in the CPU. Because of other processes, it doesn’t start to execute until time 130, and doesn’t complete till time 300, then how long is its waiting time?
(a) 220 (b) 230 (c) 240 (d) 250 (e) 260.
22. A process P consists of five pages P1, P2, P3, P4, and P5, but the operating system allows only THREE page-frames. During its lifetime the process references its pages in the order P1, P2, P3, P2, P1, P4, P1, and P5. If the memory management policy is LFU (Least Frequently Used, with FIFO used to decide ties), which page will be replaced to make room for P5?
(a) P1 (b) P2 (c) P3 (d) P4 (e) P5.
23. What is the effective access time for a page default with a probability of 40%, page fault service time of 8 milliseconds and a memory access time of 200 nanoseconds?
(a) 248.1 nanoseconds (b) 200.3 nanoseconds (c) 128.4 nanoseconds
(d) 123.2 nanoseconds (e) 124.3 nanoseconds.
24. Which of the following operations of files allows the user to erase the content of a file keeping its attributes?
(a) Repositioning within the file (b) Truncating file (c) Deleting a file
(d) Renaming a file (e) Exiting from a file.
25. Which of the following is/are the technique(s) used for counting based page replacement?
I. Least Frequently Used (lfu).
II. Most Frequently Used (MFU).
III. Least Recently Used (LRU).
(a) Only (I) above
(b) Only (II) above
(c) Only (III) above
(d) Both (I) and (II) above
(e) All (I), (II) and (III) above.
26. Which of the following is the disc scheduling algorithm that selects the request with the minimum seek time from the current head position?
(a) FCFS Scheduling (b) SSTF Scheduling (c) SCAN Scheduling (d) LOOK Scheduling (e) C-LOOK Scheduling.
27. Which of the following is not a file attribute?
(a) Name (b) Protection (c) Security (d) Size (e) Location.
28. Which of the following is not a System Threat?
(a) WORM (b) Denial of Services (c) Internet WORM (d) Viruses (e) Trojan Horse.
29. A small piece of code used to locate the appropriate memory-resident library routine is called
(a) Skeleton (b) Server (c) Client (d) Stub (e) Program.
30. In which of the following one server runs the application or applications while other servers are standby?
(a) Asymmetric clustering (b) Symmetric Clustering (c) Fragmentation (d) Clustering
(e) Waited Computing.
Section B : Problems (50 Marks)
1
a. Explain the concept of transaction atomicity.
b. Is it possible to have a deadlock involving only one single process? Explain. (5 + 5 = 10 marks)
2 Consider a system that supports 5000 users. Suppose that you want to allow 4990 of these users to be able to access one file.
a. How would you specify this protection scheme in UNIX?
b. Could you suggest another protection scheme that can be used more effectively for this purpose than the scheme provided by UNIX? (4 + 6 = 10 marks)
3 Consider a file currently consisting of 100 blocks. Assume that the file control block and the index block, in the case of indexed allocation is already in memory. Calculate how many disk I/O operations are required for contiguous, linked, and indexed- single level allocation strategies, if, for one block, the following conditions hold. In the contiguous-allocation case, assume that there is no room to grow in the beginning, but there is room to grow in the end. Assume that the block information to be added is stored in memory.
a. The block is added at the beginning.
b. The block is added in the middle.
c. The block is added at the end.
d. The block is removed from the beginning.
e. The block is removed from the end. (5 * 2 = 10 marks)
4
a. Mention the main differences between capability lists and access lists.
b. What are the three major activities of an operating system in regard to secondary-storage management?
c. Explain the differences, in terms of cost, among the three storage types volatile, nonvolatile, and stable. (3 + 3 + 4 = 10 marks)
5
a. What is PCB? Identify the information associated with a specific process.
b. Name the five major categories of system calls to give examples. (5 + 5 = 10 marks)
Section C : Applied Theory (20 Marks)
6 What is IPC? Explain the different ways to implement IPC. (10 marks)
7 Differentiate between the following terms
a. Long Time Scheduler and Short Time Scheduler
b. Preemptive Scheduling and Non-preemptive Scheduling
c. Process and Program
d. Multilevel Queue and Multilevel Feedback Queue
e. MS DOS and Windows Operating systems. (2 + 2 + 2 + 2 +2 = 10 marks)
Suggested Answers
1.
Answer : (e)
Reason : Access right controls the access of programs, processes or users to the resources defined by the system.
2.
Answer : (a)
Reason : A distributed system is a collection of processors that do not share memory.
3.
Answer : (a)
Reason : Throughput should be less related to the CPU utilization is true.
4.
Answer : (e)
Reason : Critical Section will have Progress, Mutual Exclusion and Bounded Waiting
5.
Answer : (e)
Reason : ACL stands for: Access Control List.
6.
Answer : (d)
Reason : It is general graph directory
7.
Answer : (b)
Reason : Physical Formatting is also Called as Low Level Formatting
8.
Answer : (d)
Reason : Given n processes to be scheduled on one processor. The numbers of possible different schedules are n!.
9.
Answer : (b)
Reason : The two valid semaphore operations are wait () and signal ().
10.
Answer : (a)
Reason : Access-right =
11.
Answer : (d)
Reason : The deadlocks more precisely described by RAG.
12.
Answer : (e)
Reason : PTLR stands for Page table length register
13.
Answer : (e)
Reason : Reentrant or pure code is non self modifying code.
14.
Answer : (a)
Reason : Pi requests instance of Rj.
15.
Answer : (d)
Reason : The formula for Effective access time is (1-p) * ma+p*pft
16.
Answer : (c)
Reason : (1, 0) in enhanced second chance algorithm specifies Referred but not modified.
17.
Answer : (c)
Reason : The synonym for Direct Access is Relative Access.
18.
Answer : (c)
Reason : The portion of the operating system that must remain in memory at all times called kernel.
19.
Answer : (b)
Reason : Reallocation is the process of moving a process' code and data around in main memory without having to recompile.
20.
Answer : (c)
Reason : The figure illustrates C-SCAN.
21.
Answer : (b)
Reason : Consider that a process arrives in to the system at time 20, and needs 50 time units in the CPU. Because of other processes, it doesn’t start to execute until time 130, and doesn’t complete till time 300, then its waiting time is 230.
22.
Answer : (d)
Reason : A process P consists of five pages P1, P2, P3, P4, and P5, but the operating system allows only THREE page-frames. During its lifetime the process references its pages in the order P1, P2, P3, P2, P1, P4, P1, and P5. If the memory management policy is LFU (Least Frequently Used, with FIFO used to decide ties), then P4 page will be replaced to make room for P5.
23.
Answer : (d)
Reason : The formula for effective access time =
= (1 –P) ma + P x Page fault time
= (1-.4) 200 + .4 x 8
= 123.2 nanoseconds
24.
Answer : (b)
Reason : Rather than forcing the user to delete the file and then recreate truncating, it allows all attributes remain unchanged
25.
Answer : (d)
Reason : The techniques used for counting based page replacement are Least frequently used (lfu) and Most frequently used (MFU).
26.
Answer : (a)
Reason : The disc scheduling selects the request with the minimum seek time from the current head position is FCFS Scheduling
27.
Answer : (c)
Reason : Security is not a file attribute.
28.
Answer : (e)
Reason : Trojan Horse is not a System Threat.
29.
Answer : (d)
Reason : small piece of code, stub is used to locate the appropriate memory-resident library routine.
30.
Answer : (a)
Reason : Consider that one server runs the application or applications while other servers are standby called Asymmetric clustering
Operating Systems (MC251): April 2007
Section A : Basic Concepts (30 Marks)
1. Which one of the following operating systems was written for minicomputers?
(a) MS-DOS 1.0 (b) OS/360 (c) UNIX version 7 (d) Windows NT (e) LINUX.
2. Which technique was introduced because a single job could not keep both the CPU and the I/O devices busy?
(a) Time-sharing (b) Spooling (c) Preemptive scheduling (d) Multiprogramming (e) Monoprogramming.
3. Which kind of scheduling involves activation and suspension of processes?
(a) Short-term (b) Middle-term (c) Long-term (d) Prioritised (e) Non-prioritized.
4. One needs a good practical example of a “producer-consumer” type problem. From among the following which is/are true of such a good practical example?
I. A multithreaded audio server, where a thread writes digitized sound into a circular buffer and another thread reads it over to a web page.
II. A printer spooler where files are spooled on to the printer queue, to be taken and printed by the printer driver.
III. A shared data base updated by simultaneous queries.
(a) Only (II) above
(b) Both (I) and (III) above
(c) Both (I) and (II) above
(d) Only (I) above
(e) All (I), (II) and (III) above.
5. The wait time for a process is the amount of time
(a) A process needs, to be in the running state before it is completed
(b) The process spends waiting in the ready state
(c) The process waits for all resources to be allocated to it
(d) The process spends in the blocked state
(e) The process needs for context switching.
6. Which of the following is correct with respect to all UNIX system calls?
(a) time(), chdir(), createdir(), execve()
(b) chmod(), main(), waitpid(), exit()
(c) open(), fork(), delete(), read()
(d) lseek(), stat(), link(), kill()
(e) Read(), write(), parent(), exe().
7. What is meant by ‘thrashing’ with regard to memory management?
(a) Frequent movement of pages to and from main memory to the hard disk, due to page faults
(b) Reduction of disk space in the swap partition area
(c) Illegal attempt by a process to address a forbidden memory location
(d) Is another name for a page fault
(e) Is another name for a segmentation fault.
8. The amount of time that a job waits in a ready queue for getting selected by CPU is called as
(a) Turn around time (b) Waiting time (c) Completion time (d) Submission time (e) Throughput.
9. What do you call the process of storing and restoring from PCB?
(a) Loading (b) Relocation (c) Dispatcher (d) Process (e) Context switch.
10. Which of the following memory management scheme loads all pages of a program from disk into main memory?
(a) Paging (b) Demand paging (c) Segmentation (d) Segmentation with paging (e) Demand Segmentation.
11. Which of the following page replacement algorithm uses the technique of replace that page which is not used in the near future?
(a) LRU (b) LFU (c) ORA (d) FIFO (e) MFU.
12. The set of pages that a process is currently using is called
(a) Program (b) Page Group (c) Working Group (d) Working Set (e) Software.
13. The register that contains the starting address of a program in the main memory is
(a) Address register (b) Base register (c) GPR (d) Index register (e) Limit register.
14. What is the process of converting logical address into physical address?
(a) Conversion (b) Displacement (c) Relocation (d) Transfer (e) Segmentation.
15. How does the logical memory is divided in segmentation process?
(a) Pages (b) Frames (c) Blocks (d) Cells (e) Segments.
16. Where do the O.S programs reside in main memory?
(a) User Memory area (b) Monitor Memory area (c) Heap area (d) Stack area (e) Data area.
17. In Unix, which of the following system call returns the meta data about a file?
(a) Fstat (b) Mstat (c) MetaCall (d) Sigabort (e) Fork.
18. Information in the file is processed in order, one recode after another. What is the mode of access for the above given statement?
(a) Relative (b) Sequential (c) Direct (d) Index (e) Indexed-sequential.
19. Which technique is used to recover the process from starvation situation?
(a) Paging (b) Aging (c) Compaction (d) Starvation (e) Reduction.
20. Before we store data into a disk it must be divided into sectors from where the disk controller can read and write. What do you call this process as?
(a) Low-level formatting (b) Fragmenting (c) High-level formatting (d) Cleaning (e) Portioning a disk.
21. The disk controller can be told to replace each bad sector logically with one of the spare sectors in the disk. What do you call this scheme as?
(a) Sector sparing (b) Sector slipping (c) Forwarding (d) Back word replacing (e) Sector replace.
22. Controlling the access of programs, processes or users to the resources defined by the system. What is this process called as?
(a) Prevention (b) Security (c) Protection (d) Access stop (e) Access right.
23. Which of the following symbol is used to represent the process vertex in a RAG?
(a) (b) (c) (d) (e)
24. Which of the following mechanism is used to achieve concurrency control?
(a) Clusters (b) Triggers (c) Control access (d) Cursors (e) Locks.
25. Every process before starting execution should know what resources are allocated to it. This is known as
(a) Know-to-need (b) Need-to-Know (c) Know about what (d) Need-to-use
1. Which one of the following operating systems was written for minicomputers?
(a) MS-DOS 1.0 (b) OS/360 (c) UNIX version 7 (d) Windows NT (e) LINUX.
2. Which technique was introduced because a single job could not keep both the CPU and the I/O devices busy?
(a) Time-sharing (b) Spooling (c) Preemptive scheduling (d) Multiprogramming (e) Monoprogramming.
3. Which kind of scheduling involves activation and suspension of processes?
(a) Short-term (b) Middle-term (c) Long-term (d) Prioritised (e) Non-prioritized.
4. One needs a good practical example of a “producer-consumer” type problem. From among the following which is/are true of such a good practical example?
I. A multithreaded audio server, where a thread writes digitized sound into a circular buffer and another thread reads it over to a web page.
II. A printer spooler where files are spooled on to the printer queue, to be taken and printed by the printer driver.
III. A shared data base updated by simultaneous queries.
(a) Only (II) above
(b) Both (I) and (III) above
(c) Both (I) and (II) above
(d) Only (I) above
(e) All (I), (II) and (III) above.
5. The wait time for a process is the amount of time
(a) A process needs, to be in the running state before it is completed
(b) The process spends waiting in the ready state
(c) The process waits for all resources to be allocated to it
(d) The process spends in the blocked state
(e) The process needs for context switching.
6. Which of the following is correct with respect to all UNIX system calls?
(a) time(), chdir(), createdir(), execve()
(b) chmod(), main(), waitpid(), exit()
(c) open(), fork(), delete(), read()
(d) lseek(), stat(), link(), kill()
(e) Read(), write(), parent(), exe().
7. What is meant by ‘thrashing’ with regard to memory management?
(a) Frequent movement of pages to and from main memory to the hard disk, due to page faults
(b) Reduction of disk space in the swap partition area
(c) Illegal attempt by a process to address a forbidden memory location
(d) Is another name for a page fault
(e) Is another name for a segmentation fault.
8. The amount of time that a job waits in a ready queue for getting selected by CPU is called as
(a) Turn around time (b) Waiting time (c) Completion time (d) Submission time (e) Throughput.
9. What do you call the process of storing and restoring from PCB?
(a) Loading (b) Relocation (c) Dispatcher (d) Process (e) Context switch.
10. Which of the following memory management scheme loads all pages of a program from disk into main memory?
(a) Paging (b) Demand paging (c) Segmentation (d) Segmentation with paging (e) Demand Segmentation.
11. Which of the following page replacement algorithm uses the technique of replace that page which is not used in the near future?
(a) LRU (b) LFU (c) ORA (d) FIFO (e) MFU.
12. The set of pages that a process is currently using is called
(a) Program (b) Page Group (c) Working Group (d) Working Set (e) Software.
13. The register that contains the starting address of a program in the main memory is
(a) Address register (b) Base register (c) GPR (d) Index register (e) Limit register.
14. What is the process of converting logical address into physical address?
(a) Conversion (b) Displacement (c) Relocation (d) Transfer (e) Segmentation.
15. How does the logical memory is divided in segmentation process?
(a) Pages (b) Frames (c) Blocks (d) Cells (e) Segments.
16. Where do the O.S programs reside in main memory?
(a) User Memory area (b) Monitor Memory area (c) Heap area (d) Stack area (e) Data area.
17. In Unix, which of the following system call returns the meta data about a file?
(a) Fstat (b) Mstat (c) MetaCall (d) Sigabort (e) Fork.
18. Information in the file is processed in order, one recode after another. What is the mode of access for the above given statement?
(a) Relative (b) Sequential (c) Direct (d) Index (e) Indexed-sequential.
19. Which technique is used to recover the process from starvation situation?
(a) Paging (b) Aging (c) Compaction (d) Starvation (e) Reduction.
20. Before we store data into a disk it must be divided into sectors from where the disk controller can read and write. What do you call this process as?
(a) Low-level formatting (b) Fragmenting (c) High-level formatting (d) Cleaning (e) Portioning a disk.
21. The disk controller can be told to replace each bad sector logically with one of the spare sectors in the disk. What do you call this scheme as?
(a) Sector sparing (b) Sector slipping (c) Forwarding (d) Back word replacing (e) Sector replace.
22. Controlling the access of programs, processes or users to the resources defined by the system. What is this process called as?
(a) Prevention (b) Security (c) Protection (d) Access stop (e) Access right.
23. Which of the following symbol is used to represent the process vertex in a RAG?
(a) (b) (c) (d) (e)
24. Which of the following mechanism is used to achieve concurrency control?
(a) Clusters (b) Triggers (c) Control access (d) Cursors (e) Locks.
25. Every process before starting execution should know what resources are allocated to it. This is known as
(a) Know-to-need (b) Need-to-Know (c) Know about what (d) Need-to-use
(e) Know-to-use.
26. The ability to execute an operation on an object is known as
(a) Access Right (b) Access Control (c) Domain Knowledge (d) Control Right
(e) Protection.
27. Which among the following is the time required to move the disk head to the desired track?
(a) Access Time (b) Track Time (c) Latency Time (d) Seek Time
(e) Block Time.
28. Which among the following is not shared in distributed system?
(a) CPU (b) Memory (c) I/O devices (d) Network (e) File.
29. What do you call the name of the file that does not reveal any hint of the file’s physical storage location?
(a) Location independence (b) Protection (c) Location transparency (d) File migration
(e) Inter-machine interface.
30. 1024 words occupy how many bits?
(a) 9 (b) 10 (c) 11 (d) 12 (e) 13.
Section B : Problems (50 Marks) 1. Discuss about the following O.S structures and also discuss the advantages and disadvantages of each.
a. Layered Structure.
b. Client-server Model. (5 + 5 = 10 marks)
2.
a. Write the differences between a program and a process.
b. Draw the process state diagram for a multi programmed operating system. Explain about various transitions among the states. (4 + 6 = 10 marks)
3.
a. What is thrashing? Explain different mechanisms to handle thrashing situation.
b. Consider a logical address space of 8 pages and 1024 words mapped into physical memory of 32 frames.
i. How many bits are there in logical address?
ii. How many bits are there in physical address? (6 + 4 = 10 marks)
4. Define paging? Discuss in detail how paging scheme can be implemented? Discuss advantages and disadvantages of paging scheme. (10 marks)
5. Explain different file allocation schemes and discuss merits and demerits of each scheme.
(10 marks)
Section C : Applied Theory (20 Marks)
6. Suppose that a disk has 200 tracks, numbered from 0 to 199. The drive is currently serving a request a track 50. The queue of pending requests in FIFO order is
93 38 14 124 78 130 12 140
Starting from the current head disk position, what is the total distance that the disk arm moves to satisfy all the pending requests for each of the following disk scheduling algorithms.
a) FCFS b) SSTF c) SCAN d) CSCAN e) LOOK f) CLOOK. (12 marks)
7. What is a page fault? Consider the following page reference string.
1, 2, 3, 4, 2, 1, 5, 6, 2, 1, 2, 3, 7, 6, 3, 2, 1, 2, 3, 6
How many page faults would occur for the following page replacement algorithms? Assume there are four frames in the memory.
i. ORA
ii. LRU
iii. FIFO. (8 marks)
1.
Answer : (c)
Reason: UNIX version 7 was written for minicomputers.
2.
Answer : (a)
Reason: Time sharingtechnique was introduced because a single job could not keep both the CPU and the I/O devices busy
3.
Answer : (a)
Reason: Short-term. Kind of scheduling involves activation and suspension of processes.
4.
Answer : (b)
Reason: A multithreaded audio server, where a thread writes digitized sound into a circular buffer and another thread reads it over to a web page and a shared data base updated by simultaneous queries are the suitable examples for “producer-consumer”
5.
Answer : (a)
Reason: Wait time for a process is the amount of time a process needs, to be in the running state before it is completed
6.
Answer : (a)
Reason: The given are the unix system calls time(), chdir(), createdir(), execve()
7.
Answer : (b)
Reason: Reduction of disk space in the swap partition area.
8.
Answer : (b)
Reason: The amount of time that a job waits in a ready queue for getting selected by CPU waiting time
9.
Answer : (e)
Reason: The process of storing and restoring from PCB is called context swithching
10.
Answer : (a)
Reason: Paging memory management scheme loads all pages of a program from disk into main memory.
11.
Answer : (c)
Reason: ORA page replacement algorithm use the technique of replace that page which is not used in the near future.
12.
Answer : (d)
Reason: The set of pages that a process is currently using is called- Working set
13.
Answer : (b)
Reason: The register that contains starting address of the program in the main memory is called Base register
14.
Answer : (c)
Reason: The process of converting logical address into physical address is called Relocation.
15.
Answer : (e)
Reason: In a segmentation scheme the logical memory will be divided into Segments.
16.
Answer : (b)
Reason: The place where O.S programs stored in the main memory is called Monitor Memory area.
17.
Answer : (a)
Reason: In Unix which of the following system call returns the meta data about a file. Fstat
18.
Answer : (b)
Reason: Information in the file is processed in order, one recode after another. This mode of access is called Sequential.
19.
Answer : (b)
Reason: Aging technique is used to recover the process from starvation situation
20.
Answer : (c)
Reason: Before we store data into a disk it must be divided into sectors and from where the disk controller can read and write. This is known a s highlevel formatting
21.
Answer : (a)
Reason: The disk controller can be told to replace each bad sector logically with one of the spare sectors in the disk. This scheme is known as Sector sparing
22.
Answer : (c)
Reason: Controlling the access of programs, processes or users to the resources defined by the system is known as Protection
23.
Answer : (b)
Reason: Circle is used to represent a process in RAG
24.
Answer : (e)
Reason: Locks mechanism is used to achieve concurrency control
25.
Answer : (b)
Reason: Every process before starting execution should know what resources are allocated to it. This is known as Need-to-Know.
26.
Answer : (a)
Reason: The ability to execute an operation on an object is known as Access Right
27.
Answer : (d)
Reason: The time required to move the disk head to the desired track is known as Seek Time
28.
Answer : (b)
Reason: A distributed system is a collection of processors that do not share- Memory.
29.
Answer : (c)
Reason: The name of the file does not reveal any hint of the file’s physical storage location is called Location transparency
30.
Answer : (b)
Reason: 1024=210 words. So 10 bits is the right choice.
26. The ability to execute an operation on an object is known as
(a) Access Right (b) Access Control (c) Domain Knowledge (d) Control Right
(e) Protection.
27. Which among the following is the time required to move the disk head to the desired track?
(a) Access Time (b) Track Time (c) Latency Time (d) Seek Time
(e) Block Time.
28. Which among the following is not shared in distributed system?
(a) CPU (b) Memory (c) I/O devices (d) Network (e) File.
29. What do you call the name of the file that does not reveal any hint of the file’s physical storage location?
(a) Location independence (b) Protection (c) Location transparency (d) File migration
(e) Inter-machine interface.
30. 1024 words occupy how many bits?
(a) 9 (b) 10 (c) 11 (d) 12 (e) 13.
Section B : Problems (50 Marks) 1. Discuss about the following O.S structures and also discuss the advantages and disadvantages of each.
a. Layered Structure.
b. Client-server Model. (5 + 5 = 10 marks)
2.
a. Write the differences between a program and a process.
b. Draw the process state diagram for a multi programmed operating system. Explain about various transitions among the states. (4 + 6 = 10 marks)
3.
a. What is thrashing? Explain different mechanisms to handle thrashing situation.
b. Consider a logical address space of 8 pages and 1024 words mapped into physical memory of 32 frames.
i. How many bits are there in logical address?
ii. How many bits are there in physical address? (6 + 4 = 10 marks)
4. Define paging? Discuss in detail how paging scheme can be implemented? Discuss advantages and disadvantages of paging scheme. (10 marks)
5. Explain different file allocation schemes and discuss merits and demerits of each scheme.
(10 marks)
Section C : Applied Theory (20 Marks)
6. Suppose that a disk has 200 tracks, numbered from 0 to 199. The drive is currently serving a request a track 50. The queue of pending requests in FIFO order is
93 38 14 124 78 130 12 140
Starting from the current head disk position, what is the total distance that the disk arm moves to satisfy all the pending requests for each of the following disk scheduling algorithms.
a) FCFS b) SSTF c) SCAN d) CSCAN e) LOOK f) CLOOK. (12 marks)
7. What is a page fault? Consider the following page reference string.
1, 2, 3, 4, 2, 1, 5, 6, 2, 1, 2, 3, 7, 6, 3, 2, 1, 2, 3, 6
How many page faults would occur for the following page replacement algorithms? Assume there are four frames in the memory.
i. ORA
ii. LRU
iii. FIFO. (8 marks)
1.
Answer : (c)
Reason: UNIX version 7 was written for minicomputers.
2.
Answer : (a)
Reason: Time sharingtechnique was introduced because a single job could not keep both the CPU and the I/O devices busy
3.
Answer : (a)
Reason: Short-term. Kind of scheduling involves activation and suspension of processes.
4.
Answer : (b)
Reason: A multithreaded audio server, where a thread writes digitized sound into a circular buffer and another thread reads it over to a web page and a shared data base updated by simultaneous queries are the suitable examples for “producer-consumer”
5.
Answer : (a)
Reason: Wait time for a process is the amount of time a process needs, to be in the running state before it is completed
6.
Answer : (a)
Reason: The given are the unix system calls time(), chdir(), createdir(), execve()
7.
Answer : (b)
Reason: Reduction of disk space in the swap partition area.
8.
Answer : (b)
Reason: The amount of time that a job waits in a ready queue for getting selected by CPU waiting time
9.
Answer : (e)
Reason: The process of storing and restoring from PCB is called context swithching
10.
Answer : (a)
Reason: Paging memory management scheme loads all pages of a program from disk into main memory.
11.
Answer : (c)
Reason: ORA page replacement algorithm use the technique of replace that page which is not used in the near future.
12.
Answer : (d)
Reason: The set of pages that a process is currently using is called- Working set
13.
Answer : (b)
Reason: The register that contains starting address of the program in the main memory is called Base register
14.
Answer : (c)
Reason: The process of converting logical address into physical address is called Relocation.
15.
Answer : (e)
Reason: In a segmentation scheme the logical memory will be divided into Segments.
16.
Answer : (b)
Reason: The place where O.S programs stored in the main memory is called Monitor Memory area.
17.
Answer : (a)
Reason: In Unix which of the following system call returns the meta data about a file. Fstat
18.
Answer : (b)
Reason: Information in the file is processed in order, one recode after another. This mode of access is called Sequential.
19.
Answer : (b)
Reason: Aging technique is used to recover the process from starvation situation
20.
Answer : (c)
Reason: Before we store data into a disk it must be divided into sectors and from where the disk controller can read and write. This is known a s highlevel formatting
21.
Answer : (a)
Reason: The disk controller can be told to replace each bad sector logically with one of the spare sectors in the disk. This scheme is known as Sector sparing
22.
Answer : (c)
Reason: Controlling the access of programs, processes or users to the resources defined by the system is known as Protection
23.
Answer : (b)
Reason: Circle is used to represent a process in RAG
24.
Answer : (e)
Reason: Locks mechanism is used to achieve concurrency control
25.
Answer : (b)
Reason: Every process before starting execution should know what resources are allocated to it. This is known as Need-to-Know.
26.
Answer : (a)
Reason: The ability to execute an operation on an object is known as Access Right
27.
Answer : (d)
Reason: The time required to move the disk head to the desired track is known as Seek Time
28.
Answer : (b)
Reason: A distributed system is a collection of processors that do not share- Memory.
29.
Answer : (c)
Reason: The name of the file does not reveal any hint of the file’s physical storage location is called Location transparency
30.
Answer : (b)
Reason: 1024=210 words. So 10 bits is the right choice.
Operating Systems (MC251) : October 2006
Section A : Basic Concepts (30 Marks)
1. Which of the following allows different parts of a single program to run concurrently?
(a) Multi programming (b) Multi Processing (c) Multi user (d) Multi threading (e) Multi tasking.
2. Which of the following is not the state of a process?
(a) New (b) Executing (c) Suspended (d) Waiting (e) Programming.
3. Which of the following denotes the function of Fork() method?
(a) Execute a program (b) Create a program (c) Suspend the process (d) Terminate the process (e) Swap a program.
4. An operating system is a
(a) Hardware (b) BIOS (c) Operator (d) Software (e) Firmware.
5. Graphical user interfaces (GUIs) make it easy for users to interact with the operating system by
(a) Using a light pen system
(b) Using finger as an input device
(c) Pointing cursor at icons and clicking on them
(d) Using specially programmed function keys on the keyboard
(e) Writing simple code using commands.
6. Which of the following becomes an important characteristic in the RR scheduling?
(a) CPU burst time (b) Time Quantum (c) Priority (d) Number of Processors (e) Number of Jobs.
7. Which one of the following is a synonym for Process Control Block?
(a) Process Blocking (b) Control Blocking (c) Task control block (d) Disabled block (e) Interruption.
8. Acronym for IPC is
(a) Internet Protocol Control (b) Interface Process Communication (c) Intranet Program Control (d) Internet Process Control (e) Inter Process Communication.
9. Which of the following is a technique of gradually increasing the priority of processes that wait in the system for a long time?
(a) Starvation (b) Dispatcher (c) Blocking (d) Termination (e) Aging.
10. A device driver is a
(a) Process State (b) Queue (c) person (d) program (e) Peripheral.
11. Which of the following describe the deadlocks more precisely?
(a) Pie graph (b) Resource Allocation graph (c) Bar graph (d) Gantt graph (e) XY graph. 12. Which one of the following is not a condition for deadlock?
(a) Mutual Exclusion (b) Progress (c) Hold and Wait (d) No preemption (e) Circular Wait.
13. Which of the following is an external criteria for assigning a priority to a job?
(a) Memory Requirements (b) Number of open files (c) I/O burst time (d) Political factors (e) Time limits.
14. Acronym for TLB is
(a) Translation look-side buffer
(b) Translation look buffer
(c) Translation level buffer
(d) Translation look-aside buffer
(e) Translation load-side buffer.
15. Which of the following is/are non self modifying code(s)?
I. Machine code.
II. Critical section code.
III. Reentrant code.
(a) Only (I) above
(b) Only (II) above
(c) Only (III) above
(d) Both (I) and (II) above
(e) Both (I) and (III) above.
16. Which of the following defines the term “Roll back”?
(a) Terminating (b) Blocking (c) Undoing (d) Redoing (e) Creating.
17. Identify the disadvantage of main memory caches.
(a) Permit workstations to be diskless
(b) Data can be accessed more quickly
(c) Performance speedup in bigger memories
(d) Permits a single caching mechanism for servers and users
(e) Time consumed for recovery.
18. Access-right =
(a) (b)
(c) (d) (e)
19. Which of the following is not a System Threat?
(a) WORM (b) Denial of Services (c) Internet WORM (d) Viruses (e) Trojan Horse.
20. Consider the following figure to identify the disk scheduling algorithms among the given options.
(a) SCAN (b) SSTF (c) C-SCAN (d) C-LOOK (e) LOOK.
21. How many different levels are used to arrange RAID?
(a) 4 (b) 6 (c) 5 (d) 3 (e) 8.
22. Which of the following is not a file attribute?
(a) Name (b) Protection (c) Security (d) Size (e) Location.
23. Consider the following figure to identify the disk allocation techniques among the given options.
(a) Sequential Allocation (b) Indexed Allocation (c) Linked Allocation
(d) Contiguous Allocation (e) Blocked Allocation.
24. Block number =
(a) (number of bits per word) * (number of 0-value words) + offset of first 1 bit
(b) (number of bits per word) +(number of 0-value words) * offset of first 1 bit
(c) (number of bits per word) * (number of 0-value words) / offset of first 1 bit
(d) (number of bits per word) / (number of 0-value words) + offset of first 1 bit
(e) (number of bits per word) * (number of 0-value words) * offset of first 1 bit. Answer >
25. Which of the following is a block of available memory?
(a) Break (b) Segment (c) Allocated partitions (d) Hole (e) Sector.
26. Acronym for PTLR is
(a) Page Table Link Register
(b) Partition Table Load Register
(c) Page Table Length Register
(d) Process Table Length Register
(e) Page Table Length Relocation.
27. Which of the following is the type of Semaphore?
(a) Sorting Semaphore (b) Counting Semaphore (c) Calculating Semaphore (d) Manipulative Semaphore (e) Derived Semaphore.
28. Which of the following is not a problem of Synchronization?
(a) Bounded Buffer (b) Readers-writers (c) Dinning philosopher
(d) Dinning Professor (e) None of the above.
29. High-level synchronization construct that allows the safe sharing of an abstract data type among concurrent processes is
(a) Monitor (b) System (c) MOS (d) Counter (e) Multi threading.
30. Acronym for RMI is
(a) Remote Method Implementation
(b) Remote Memory Invocation
(c) Real time Method Invocation
(d) Remote Method Invocation
(e) Reliable Method Invocation.
Section B : Problems (50 Marks)
1. Draw the state transition diagram of a process and label each state and each transition in the diagram. Briefly explain the transitions and the queues in which the process will be waiting.
(10 marks)
2.
a. Mike, the manager, has the right to read and change any files in his company. Tom is one of the team leaders in the company. He has the right to control all files in the team and read other teams’ file only. Tom has three assistants Jim, David and John. Each of them is working on a project. The assistants can read and execute others’ work in the team, but they cannot write in it or access the files of other teams. Now, you are the system administrator of the company. Set the access permission for them in UNIX.
b. From the below figure, Compute the average waiting time for the FCFS and SRTF scheduling.
(6 + 4 = 10 marks)
3.
a. What is the main characteristic of TLB (Translation Lookaside Buffer) in memory management unit of an Operating-System?
b. If a memory reference takes 800 nanoseconds; a TLB reference takes 60 nanoseconds; and the hit-rate is 95%, what is the effective memory reference time? How much speed-up we gained using TLB technique compared to the pure paging with no TLB? Show your calculations below. (4 + 6 = 10 marks)
4. Consider five processes P0 to P4 that use four resource types with the following snapshot
at time t0. Answer the following questions:
Allocation A B CD Request A B CD Available A B CD
P0
0 1 0 2
0 2 0 0
4 0 0 3
P1
2 0 0 1
1 0 1 1
P2
1 0 1 0
0 1 0 1
P3
2 1 0 1
0 0 0 0
P4
0 0 2 1
0 0 3 1
a. In the context of deadlock detection, do the processes need to declare the number of resources they NEED to complete their work (Yes or No)? Why?
b. In the above table, briefly explain whether the following equation among the matrices is correct or not? Allocation + Request = Maximum need
c. Most of the current operating systems only rely on “deadlock detection” mechanism not the deadlock prevention or avoidance. Why?
d. At time T1 > T0 process P0 requests 3 resources of type C and process P3 requests 2 resources of type A. The operating system does not grant the resource requests before time T2 T1. Below draw two tables that show the changes that will occur at “time T1” and at “time T2”.
e. At time T2 the operating system also applies the deadlock detection algorithm. If the system is in the deadlock situation, determine the processes involved in the deadlock and the value of the vector Available. If the system is not in deadlock indicate the sequence of changing the values of vector Available and its final value (3 + 3 + 3 + 6 + 5 = 20 marks)
Section C : Applied Theory (20 Marks)
5.
a. For contiguous, linked and indexed disk allocation techniques specify its characteristics in terms of:
1. Ease of growth of file size.
2. How the free disk blocks are assigned.
3. Ease of random access to a location in a file.
4. Advantages and disadvantages.
b. Name four items in the Process Control Block (PCB). (6 + 4 = 10 marks)
6. What are the main characteristics of the following types of operating systems in terms of resource utilization and the type of services they provide?
a. Batch Processing Systems.
b. Time Sharing Systems.
c. Personal Computers.
d. Handheld Computers. (10 marks)
Suggested Answers
1.
Answer : (d)
Reason: Multi threading allows different parts of a single program to run concurrently.
2.
Answer : (e)
Reason: Programming is not the state of a process.
3.
Answer : (b)
Reason: Fork() is a command to Create.
4.
Answer : (d)
Reason: An operating system is Software.
5.
Answer : (c)
Reason: Graphical user interfaces (or GUIs) make it easy for users to interact with the operating system by pointing at icons and clicking on them.
6.
Answer : (b)
Reason: The RR scheduling depends on the Time Quantum.
7.
Answer : (c)
Reason: Process Control Block is also called as Task control block.
8.
Answer : (e)
Reason: IPC stands for Inter Process Communication.
9.
Answer : (e)
Reason: Aging is a technique of gradually increasing the priority of processes that wait in the system or a long time.
10.
Answer : (d)
Reason: A device driver is a program.
11.
Answer : (b)
Reason: Deadlocks can be described more precisely in terms of a graph called Resource Allocation graph.
12.
Answer : (b)
Reason: Progress is not a condition for deadlock.
13.
Answer : (d)
Reason: Political factors is a external criteria for assigning a priority to a job.
14.
Answer : (d)
Reason: TLB stands for Translation look-aside buffer.
15.
Answer : (c)
Reason: Reentrant code is a non self modifying code.
16.
Answer : (c)
Reason: Roll back is Undoing a process.
17.
Answer : (e)
Reason: The disadvantage of main memory caches is Time Consumed (high) for recovery.
18.
Answer : (a)
Reason: Access-right =
19.
Answer : (e)
Reason: Trojan Horse is not a System Threat but program threat.
20.
Answer : (c)
Reason: illustrates C-SCAN
21.
Answer : (b)
Reason: RAID is arranged in 6 different levels.
22.
Answer : (c)
Reason: Security is not a file attribute.
23.
Answer : (b)
Reason: illustrates Indexed Allocation.
24.
Answer : (a)
Reason: Block number =(number of bits per word) * (number of 0-value words) + offset of first 1 bit.
25.
Answer : (d)
Reason: Hole is a block of available memory.
26.
Answer : (c)
Reason: Acronym for PTLR is Page Table Length Register.
27.
Answer : (b)
Reason: Counting Semaphore is the type of a semaphore.
28.
Answer : (d)
Reason: Dinning Professor is not a problem of Synchronization.
29.
Answer : (a)
Reason: High-level synchronization construct that allows the safe sharing of an abstract data type among concurrent processes is Monitor.
30.
Answer : (d)
Reason: Acronym for RMI is Remote Method Invocation.
1. Which of the following allows different parts of a single program to run concurrently?
(a) Multi programming (b) Multi Processing (c) Multi user (d) Multi threading (e) Multi tasking.
2. Which of the following is not the state of a process?
(a) New (b) Executing (c) Suspended (d) Waiting (e) Programming.
3. Which of the following denotes the function of Fork() method?
(a) Execute a program (b) Create a program (c) Suspend the process (d) Terminate the process (e) Swap a program.
4. An operating system is a
(a) Hardware (b) BIOS (c) Operator (d) Software (e) Firmware.
5. Graphical user interfaces (GUIs) make it easy for users to interact with the operating system by
(a) Using a light pen system
(b) Using finger as an input device
(c) Pointing cursor at icons and clicking on them
(d) Using specially programmed function keys on the keyboard
(e) Writing simple code using commands.
6. Which of the following becomes an important characteristic in the RR scheduling?
(a) CPU burst time (b) Time Quantum (c) Priority (d) Number of Processors (e) Number of Jobs.
7. Which one of the following is a synonym for Process Control Block?
(a) Process Blocking (b) Control Blocking (c) Task control block (d) Disabled block (e) Interruption.
8. Acronym for IPC is
(a) Internet Protocol Control (b) Interface Process Communication (c) Intranet Program Control (d) Internet Process Control (e) Inter Process Communication.
9. Which of the following is a technique of gradually increasing the priority of processes that wait in the system for a long time?
(a) Starvation (b) Dispatcher (c) Blocking (d) Termination (e) Aging.
10. A device driver is a
(a) Process State (b) Queue (c) person (d) program (e) Peripheral.
11. Which of the following describe the deadlocks more precisely?
(a) Pie graph (b) Resource Allocation graph (c) Bar graph (d) Gantt graph (e) XY graph. 12. Which one of the following is not a condition for deadlock?
(a) Mutual Exclusion (b) Progress (c) Hold and Wait (d) No preemption (e) Circular Wait.
13. Which of the following is an external criteria for assigning a priority to a job?
(a) Memory Requirements (b) Number of open files (c) I/O burst time (d) Political factors (e) Time limits.
14. Acronym for TLB is
(a) Translation look-side buffer
(b) Translation look buffer
(c) Translation level buffer
(d) Translation look-aside buffer
(e) Translation load-side buffer.
15. Which of the following is/are non self modifying code(s)?
I. Machine code.
II. Critical section code.
III. Reentrant code.
(a) Only (I) above
(b) Only (II) above
(c) Only (III) above
(d) Both (I) and (II) above
(e) Both (I) and (III) above.
16. Which of the following defines the term “Roll back”?
(a) Terminating (b) Blocking (c) Undoing (d) Redoing (e) Creating.
17. Identify the disadvantage of main memory caches.
(a) Permit workstations to be diskless
(b) Data can be accessed more quickly
(c) Performance speedup in bigger memories
(d) Permits a single caching mechanism for servers and users
(e) Time consumed for recovery.
18. Access-right =
(a) (b)
(a) WORM (b) Denial of Services (c) Internet WORM (d) Viruses (e) Trojan Horse.
20. Consider the following figure to identify the disk scheduling algorithms among the given options.
(a) SCAN (b) SSTF (c) C-SCAN (d) C-LOOK (e) LOOK.
21. How many different levels are used to arrange RAID?
(a) 4 (b) 6 (c) 5 (d) 3 (e) 8.
22. Which of the following is not a file attribute?
(a) Name (b) Protection (c) Security (d) Size (e) Location.
23. Consider the following figure to identify the disk allocation techniques among the given options.
(a) Sequential Allocation (b) Indexed Allocation (c) Linked Allocation
(d) Contiguous Allocation (e) Blocked Allocation.
24. Block number =
(a) (number of bits per word) * (number of 0-value words) + offset of first 1 bit
(b) (number of bits per word) +(number of 0-value words) * offset of first 1 bit
(c) (number of bits per word) * (number of 0-value words) / offset of first 1 bit
(d) (number of bits per word) / (number of 0-value words) + offset of first 1 bit
(e) (number of bits per word) * (number of 0-value words) * offset of first 1 bit. Answer >
25. Which of the following is a block of available memory?
(a) Break (b) Segment (c) Allocated partitions (d) Hole (e) Sector.
26. Acronym for PTLR is
(a) Page Table Link Register
(b) Partition Table Load Register
(c) Page Table Length Register
(d) Process Table Length Register
(e) Page Table Length Relocation.
27. Which of the following is the type of Semaphore?
(a) Sorting Semaphore (b) Counting Semaphore (c) Calculating Semaphore (d) Manipulative Semaphore (e) Derived Semaphore.
28. Which of the following is not a problem of Synchronization?
(a) Bounded Buffer (b) Readers-writers (c) Dinning philosopher
(d) Dinning Professor (e) None of the above.
29. High-level synchronization construct that allows the safe sharing of an abstract data type among concurrent processes is
(a) Monitor (b) System (c) MOS (d) Counter (e) Multi threading.
30. Acronym for RMI is
(a) Remote Method Implementation
(b) Remote Memory Invocation
(c) Real time Method Invocation
(d) Remote Method Invocation
(e) Reliable Method Invocation.
Section B : Problems (50 Marks)
1. Draw the state transition diagram of a process and label each state and each transition in the diagram. Briefly explain the transitions and the queues in which the process will be waiting.
(10 marks)
2.
a. Mike, the manager, has the right to read and change any files in his company. Tom is one of the team leaders in the company. He has the right to control all files in the team and read other teams’ file only. Tom has three assistants Jim, David and John. Each of them is working on a project. The assistants can read and execute others’ work in the team, but they cannot write in it or access the files of other teams. Now, you are the system administrator of the company. Set the access permission for them in UNIX.
b. From the below figure, Compute the average waiting time for the FCFS and SRTF scheduling.
(6 + 4 = 10 marks)
3.
a. What is the main characteristic of TLB (Translation Lookaside Buffer) in memory management unit of an Operating-System?
b. If a memory reference takes 800 nanoseconds; a TLB reference takes 60 nanoseconds; and the hit-rate is 95%, what is the effective memory reference time? How much speed-up we gained using TLB technique compared to the pure paging with no TLB? Show your calculations below. (4 + 6 = 10 marks)
4. Consider five processes P0 to P4 that use four resource types with the following snapshot
at time t0. Answer the following questions:
Allocation A B CD Request A B CD Available A B CD
P0
0 1 0 2
0 2 0 0
4 0 0 3
P1
2 0 0 1
1 0 1 1
P2
1 0 1 0
0 1 0 1
P3
2 1 0 1
0 0 0 0
P4
0 0 2 1
0 0 3 1
a. In the context of deadlock detection, do the processes need to declare the number of resources they NEED to complete their work (Yes or No)? Why?
b. In the above table, briefly explain whether the following equation among the matrices is correct or not? Allocation + Request = Maximum need
c. Most of the current operating systems only rely on “deadlock detection” mechanism not the deadlock prevention or avoidance. Why?
d. At time T1 > T0 process P0 requests 3 resources of type C and process P3 requests 2 resources of type A. The operating system does not grant the resource requests before time T2 T1. Below draw two tables that show the changes that will occur at “time T1” and at “time T2”.
e. At time T2 the operating system also applies the deadlock detection algorithm. If the system is in the deadlock situation, determine the processes involved in the deadlock and the value of the vector Available. If the system is not in deadlock indicate the sequence of changing the values of vector Available and its final value (3 + 3 + 3 + 6 + 5 = 20 marks)
Section C : Applied Theory (20 Marks)
5.
a. For contiguous, linked and indexed disk allocation techniques specify its characteristics in terms of:
1. Ease of growth of file size.
2. How the free disk blocks are assigned.
3. Ease of random access to a location in a file.
4. Advantages and disadvantages.
b. Name four items in the Process Control Block (PCB). (6 + 4 = 10 marks)
6. What are the main characteristics of the following types of operating systems in terms of resource utilization and the type of services they provide?
a. Batch Processing Systems.
b. Time Sharing Systems.
c. Personal Computers.
d. Handheld Computers. (10 marks)
Suggested Answers
1.
Answer : (d)
Reason: Multi threading allows different parts of a single program to run concurrently.
2.
Answer : (e)
Reason: Programming is not the state of a process.
3.
Answer : (b)
Reason: Fork() is a command to Create.
4.
Answer : (d)
Reason: An operating system is Software.
5.
Answer : (c)
Reason: Graphical user interfaces (or GUIs) make it easy for users to interact with the operating system by pointing at icons and clicking on them.
6.
Answer : (b)
Reason: The RR scheduling depends on the Time Quantum.
7.
Answer : (c)
Reason: Process Control Block is also called as Task control block.
8.
Answer : (e)
Reason: IPC stands for Inter Process Communication.
9.
Answer : (e)
Reason: Aging is a technique of gradually increasing the priority of processes that wait in the system or a long time.
10.
Answer : (d)
Reason: A device driver is a program.
11.
Answer : (b)
Reason: Deadlocks can be described more precisely in terms of a graph called Resource Allocation graph.
12.
Answer : (b)
Reason: Progress is not a condition for deadlock.
13.
Answer : (d)
Reason: Political factors is a external criteria for assigning a priority to a job.
14.
Answer : (d)
Reason: TLB stands for Translation look-aside buffer.
15.
Answer : (c)
Reason: Reentrant code is a non self modifying code.
16.
Answer : (c)
Reason: Roll back is Undoing a process.
17.
Answer : (e)
Reason: The disadvantage of main memory caches is Time Consumed (high) for recovery.
18.
Answer : (a)
Reason: Access-right =
19.
Answer : (e)
Reason: Trojan Horse is not a System Threat but program threat.
20.
Answer : (c)
Reason: illustrates C-SCAN
21.
Answer : (b)
Reason: RAID is arranged in 6 different levels.
22.
Answer : (c)
Reason: Security is not a file attribute.
23.
Answer : (b)
Reason: illustrates Indexed Allocation.
24.
Answer : (a)
Reason: Block number =(number of bits per word) * (number of 0-value words) + offset of first 1 bit.
25.
Answer : (d)
Reason: Hole is a block of available memory.
26.
Answer : (c)
Reason: Acronym for PTLR is Page Table Length Register.
27.
Answer : (b)
Reason: Counting Semaphore is the type of a semaphore.
28.
Answer : (d)
Reason: Dinning Professor is not a problem of Synchronization.
29.
Answer : (a)
Reason: High-level synchronization construct that allows the safe sharing of an abstract data type among concurrent processes is Monitor.
30.
Answer : (d)
Reason: Acronym for RMI is Remote Method Invocation.
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