MIDTERM Examination #1

operating system concepts

03-60-330-01 Fall 2009

University of Windsor

School of Computer Science

Please read carefully before you start
1.  This is a CLOSED book test; no notes, textbooks, calculators or computer aids are allowed.
2.  PRINT your name legibly and clearly with your Student ID in the spaces indicated on the Scantron sheet.
3.  You will be asked to sign your name once before leaving the exam room (sign-out). By doing so you state agreement to the terms below
I agree to the above terms and will neither receive nor give unauthorized help on this exam.
4.  All questions are multiple choice. Circle the single response which best answers each question.
5.  Place all responses on the approved Scantron marking sheet using PENCIL.
6.  You are not allowed to give or receive unauthorized help with your test. Any misconduct, as outlined by the Senate bylaw 31 article I, will be reported accordingly.
7.  You have 75 minutes to complete this test.
8.  You may keep this question paper following the examination. A photocopy of your Scantron sheet will be returned to you.
9.  The maximum mark is 62.
Good Luck!

ANSWER SHEET

This copy contains notes about appeals on certain questions, notably: 20, 23, 33 and 36. See those questions for added comments.
All questions are Multiple Choice. In each Multiple Choice question, 4 responses are provided – you are to choose only one response which best answers the question. Circle the letter A, B, C or D (one only).

If an error is made you must carefully erase the error and then fill in the circle you intend to choose.

USE PENCIL ONLY

1. / In what way is an operating system like a government?
A) / It seldom functions correctly.
B) / It creates an environment within which other programs can do useful work.
C) / It performs most useful functions by itself.
D) / It is always concerned primarily with the individual's needs.
2. / Embedded computers typically run on a ____ operating system.
A) / real-time
B) / Windows XP
C) / network
D) / clustered
3. / A circular queue is the most appropriate data structure for ______scheduling.
A) / RR
B) / FCFS
C) / SJF
D) / Multi-level
4. / Turnaround time refers to the amount of time ______.
A) / that CPU utilization is minimized
B) / needed to execute a particular process
C) / a process has been waiting in the ready queue
D) / it takes from when a request was submitted until the first action is produced
5. / The major difficulty in designing a layered operating system approach is ____.
A) / making sure each layer is easily converted to modules
B) / making sure that each layer hides certain data structures, hardware, and operations from higher-level layers
C) / debugging a particular layer
D) / appropriately defining the various layers
6. / Which of the following is a property of peer-to-peer systems?
A) / Clients and servers are not distinguished from one another.
B) / Separate machines act as either the client of the server but not both.
C) / They do not offer any advantages over traditional client-server systems.
D) / They suffer from the server acting as the bottleneck in performance.
7. / In multiprocessor environments, two copies of the same data may reside in the local cache of each CPU. Whenever one CPU alters the data, the cache of the other CPU must receive an updated version of this data. This is called Cache ______.
A) / redundancy
B) / integrity
C) / coherency
D) / normalization
8. / Which of the following is not considered a resource that may be allocated by an operating system?
A) / CPU
B) / storage device
C) / file system
D) / memory
9. / Two important design issues for cache memory are ____.
A) / speed and volatility
B) / size and replacement policy
C) / power consumption and reusability
D) / size and access privileges
10. / Most often, application programs access system resources using ______.
A) / system calls
B) / kernel threads
C) / user threads
D) / application program interfaces
11. / CPU registers are often used to ______.
A) / pass parameters to the operating system
B) / store values for reuse by other user programs
C) / save memory for storing programs
D) / None of the above responses are correct.
12. / The resource pyramid, with CPU registers and cache memories at the top and tape drive storage at the bottom, reflects which of the following problems of computer design and operating system management?
A) / Resource Allocation
B) / Speed to Cost tradeoff
C) / Expertise to Transparency issue
D) / Persistency versus Volatility
13. / Which of the following is not an operating system?
A) / Linux
B) / Solaris
C) / Windows XP
D) / Oracle
14. / Which of the following is an example of a systems program?
A) / command interpreter
B) / Web browser
C) / text formatter
D) / database system
15. / If a program terminates abnormally, a dump of memory may be examined by a ____ to determine the cause of the problem.
A) / module
B) / debugger
C) / shell
D) / control card
16. / A message passing model is ____.
A) / easier to implement than a shared memory model for intercomputer communication
B) / is faster than the shared memory model
C) / a network protocol and does not apply to operating systems
D) / is only useful for small simple operating systems
17. / An advantage to using a higher-level language to implement an operating system is ______.
A) / the code can be written faster, is more compact, and is easier to understand and debug
B) / modern computer science students do not learn machine language programming
C) / an operating system is far easier to port to some other hardware if it is written in a higher-level language
D) / Both A and C are correct responses
18. / For a single-processor system ______.
A) / processes spend long times waiting to execute
B) / there will never be more than one running process
C) / input-output always causes CPU slowdown
D) / process scheduling is always optimal
19. / Policy ____.
A) / determines how to do something
B) / determines what will be done
C) / is not likely to change across places
D) / is not likely to change over time
20. / In RR scheduling, the time quantum should be ______the context-switch time.
A) / small with respect to
B) / large with respect to
C) / the same size as
D) / irrelevant to

NOTE: It was reported that a sample midterm had the incorrect answer for this question. The answer supplied above is correct – lectures and textbook information always takes precedence over mistakes (even instructor mistakes) so no appeals will be granted on this.

21. / Context switching between processes is carried out by the
A) / dispatcher
B) / short term scheduler
C) / interrupt handler
D) / thread manager
22. / An optimal job scheduling scheme is
A) / RR
B) / FCFS
C) / SJF
D) / Priority
23. / A microkernel is a kernel ____.
A) / that is stripped of all nonessential components
B) / that is compressed before loading in order to reduce its resident memory size
C) / that is compiled to produce the smallest size possible when stored to disk
D) / containing many components that are optimized to reduce resident memory size

NOTE: It was reported by several students that in the lectures, Dr. Kent had consistently used the phrase “stripping away” in reference to the size and nature of micro-kernels. This is indeed the case, so as a result of instructor initiated confusion, either A or B will be accepted as correct – the actual correct answer is B, however.

24. / Which of the following pieces of information is least useful to the SYSGEN program of an operating system?
A) / the CPU being used
B) / amount of memory available
C) / what applications to install
D) / operating-system options such as buffer sizes or CPU scheduling algorithms
25. / In a virtual machine, each program believes that it has ____.
A) / multiple processors
B) / its own memory
C) / another "virtual" computer to assist in its operations
D) / more memory than is physically available on the machine
26. / The two modes of operation of an operating system are called ______.
A) / process and kernel
B) / ready and running
C) / interrupt and system
D) / kernel and user
27. / An operating system may be viewed as a resource allocator of such things as CPU time, memory space, file-storage space, I/O devices, and so on, due to the requirement that ______.
A) / such things need to allocated to be useful for operating systems to work
B) / conflicts of resource usage must not be permitted to happen
C) / computer users must be satisfied that resources are available on request
D) / resources be used efficiently by users
28. / A ____ can be used to prevent a user program from never returning control to the operating system.
A) / portal
B) / program counter
C) / firewall
D) / timer
29. / Bootstrap programs must be provided using ______.
A) / volatile memory
B) / erasable-programmable memory
C) / non-volatile ROM devices
D) / special magnetic disk tracks
30. / Medium-term scheduling is performed ______.
A) / typically on submitted jobs
B) / when processes must be moved from waiting to ready state
C) / on processes in the ready queue
D) / None of the above are correct.
31. / An I/O-bound process ______.
A) / spends equal time seeking I/O operations and doing computational work
B) / spends more of its time doing computational work than seeking I/O operations
C) / spends more of its time seeking I/O operations than doing computational work
D) / spends less of its time seeking I/O operations than doing computational work
32. / The ____ of a process contains temporary data such as function parameters, return addresses, and local variables.
A) / text section
B) / data section
C) / program counter
D) / stack
33. / The following are valid process states.
A) / Next, Running, Halting
B) / Terminating, Waiting, Threshing
C) / Running, Blocked, Waiting
D) / None of these responses is correct

NOTE. The answer above is correct and not subject to appeal. Some students asked about the fact that the 5-state model we focused on does not include Blocked state, however, this and other state modifications to 7, 8, 9 and up to 11 state process models were discussed. Blocked and Suspended state modifications were discussed.

34. / A CPU-bound process ______.
A) / infrequently requests I/O operations and spends more of its time performing computational work
B) / frequently requests I/O operations and spends more of its time performing computational work
C) / infrequently requests I/O operations and spends less of its time performing computational work
D) / frequently requests I/O operations and spends less of its time performing computational work
35. / A process control block ____.
A) / includes information on the process's state
B) / stores the address of the next instruction to be processed by a different process
C) / determines which process is to be executed next
D) / is an example of a process queue
36. / The most common secondary storage device is ____.
A) / random access memory
B) / dynamic random access memory
C) / tape drive
D) / magnetic disk

NOTE: Dr. Kent reviewed the lectures and textbook – there is sufficient ambiguity in this question about tape drives versus disks, due to usage in the actual market (circa 2008-2010) that he will permit correct answers as C or D.

37. / A thread control block ______.
A) / is managed by the parent process
B) / contains the same information as the process control block
C) / has the identical structure as the process control block
D) / does not include information about the parent process resource allocation
38. / The list of processes waiting for a particular I/O device is called a(n) ____.
A) / standby queue
B) / device queue
C) / ready queue
D) / interrupt queue
39. / When a child process is created, which of the following is a possibility in terms of the execution or address space of the child process?
A) / The child process runs concurrently with the parent.
B) / The child process has a new program loaded into it.
C) / The child is a duplicate of the parent.
D) / All of the above
40. / In a(n) ____ temporary queue, the sender must always block until the recipient receives the message.
A) / zero capacity
B) / variable capacity
C) / bounded capacity
D) / unbounded capacity
41. / Marshalling refers to ______.
A) / packaging parameters in a form suitable for network transmission
B) / initiating a remote procedure call to a networked computer
C) / leading the packet train in TCP/IP messaging
D) / ordering processes in state queues
42. / A program is ______.
A) / another name for a process
B) / an active entity
C) / a passive entity
D) / All of the above responses are correct.
43. / Programs are capable of ______.
A) / executing concurrently
B) / performing data transfer operations
C) / performing logic
D) / None of the above responses is correct
44. / ____ scheduling is approximated by predicting the next CPU burst with an exponential average of the measured lengths of previous CPU bursts.
A) / Multilevel queue
B) / RR
C) / FCFS
D) / SJF
45. / The ____ scheduling algorithm is designed especially for time-sharing systems.
A) / SJF
B) / FCFS
C) / RR
D) / Multilevel queue
46. / Which of the following scheduling algorithms must be nonpreemptive?