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____ is the state of processor, when a process is waiting for some event to occur

wait state

Which of the following process state transitions are illegal?

waiting -> running

The ready list in an operating system contains jobs ________

waiting for the processor to be allotted to them

Thrashing occurs ________

when excessive swapping takes place

A page fault occurs

when the page is not in the memory

Page replacement algorithms determine

which page to remove to provide space for an incoming page

Which of the following statements is incorrect about Translation Look-aside Buffer (TLB)?

A TLB miss implies a disk operation will follow

What statement about the major difference between a thread and a process is true

A process can contain multiple threads

When a process is created, which of the following actions occur?

A process descriptor is allocated for the process

Which statement about processes is false?

A process information is stored in the process data block

Context Switching is

part of interrupt handling

A entry of the Process table is called:

process control block

Which of the following is not a disk scheduling algorithm?

working set

Suppose that the following processes arrive for execution at following. Waiting time of the processes in order from P1 to P3 by Round Robin algorithm with quantum time is 3 are

19, 16, 9

Consider the following set of processes with arrival times and CPU execution times given in milliseconds. A process with a larger priority number has a higher priority. Calculate the average waiting times for nonpreemptive SJF scheduling

19.4 msec

10 (2311) Which is the correct description of transitions between process states below? (see picture)

1: Process blocks for input; 2: Scheduler picks another process; 3: Scheduler picks this process; 4: Input becomes available

Which is the correct description of transitions between process states below? (see picture)

1: Process blocks for input; 2: Scheduler picks another process; 3: Scheduler picks this process; 4: Input becomes available

Which of the following is not correct about the reliability of different RAID levels?

All RAID levels can survive one disk crash

Which of the following statements is incorrect about timesharing and multiprogramming systems?

All multiprogramming systems are timesharing systems

Which of the following is contained in Process Control Block (PCB)?

All of the Above

An example of the key differences that can exist across (and even in) classes of I/O devices is:

All of the above

File Structure can be:

All of the above

The following requirement must be met by any facility or capability that is to provide support for mutual exclusion:

All of the above

The operating system manages ________

All of the above

What are the allocation methods of disk blocks for files:

All of the above

What is Software proposal in the solution of Mutual exclusion with Busy waiting

All of the above

What is correct about trap instructions and interrupts

All of the above

Which is the difference between personal computers and mainframe computers

All of the above

Which of the following is a criterion to evaluate a scheduling algorithm?

All of the above

Deadlock occur when the system have

All of the above are correct

Which of the following instructions should be privileged?

All of the above are correct

Suppose that the following processes arrive for execution at following. Response time of the processes in order from P1 to P3 by Round Robin algorithm with quantum time is 3 are

All of the above are incorrect

A operation concerning Stable Storage is:

All of the other choices

As one proceeds down the memory hierarchy (from inboard memory to offline storage), the following conditions apply:

All of the other choices

DMA operations require the following information from the processor

All of the other choices

File Structure can be:

All of the other choices

If a system is deadlocked, no processes can

All of the other choices

The absolute pathname of a file in Linux is with respect to the

All of the other choices

The following requirement must be met by any facility or capability that is to provide support for mutual exclusion:

All of the other choices

The task of subdividing memory between the OS and processes is performed automatically by the OS and is called: Memory Management

All of the other choices

Where should be put the page replacement algorithm In Mach model of Page fault handling with an external pager?

All of the other choices

Which of the following statements about semaphores is true?

All of the other choices

List out some reasons for process termination

All of the others

The selected thread runs on the CPU until one of the following occurs

All of the others

What are Nonvolatile storage devices

All of the others

Which of the following are Scheduling algorithms

All of the others

Which of the following is true for the algorithms for allocating regions of contiguous memory

All of the others

Which of the following statements about semaphores is true?

All of the others

Which of these are synchronization techniques?

All of the others

What is correct about trap instructions and interrupts?

All ofthe other choices

Dijkstra's Banker's Algorithm require the system to maintain the resource information for each process, including:

B and C

Which deadlock condition does "Ordering resources numerically" attack?

Circular-wait condition (Circular wait condition)

Which is not a goal of a sheduling algorithm for all systems?

Balance

Which scheduling algorithm can avoid deadlock?

Banker's algorithm

Which is not the method for handing deadlocks

Deadlock Detention

The earliest OS is

Monolithic

CPU scheduling is the basis of ________ operating systems

Multiprogramming

Steps for statically binding addresses include the following except

Run time rebinding

In a process scheduling, the mechanism for scheduling and policy can be set by _____________ and _____________ respectively

Kernel & user process

What is the costs associated with the technique When virtual memory is implemented in a computing system.?

Adding Hardware

The thread table records primarily the state of execution: program counter, registers, and stack. The process table records in addition such information as address space, accounting information, parent and child processes, and open files

All of the others are true

Which of the following statements about critical sections is false?

All threads must wait whenever any critical section is occupied

The purpose of process synchronization is?

Avoid races with respect to access to a shared resources

Which is not a primary reason for providing an environment that allows process cooperation:

Concurrency

Saving the state of the old process and loading the saved state of the new process is called ________

Context Switch

Switching the CPU to another Process requires to save state of the old process and loading new process state is called as __________

Context Switch

Which ?le allocation method suffers from disk fragmentation (except for internal fragmentation in the last block)?

Contiguous allocation

In a system employing a paging scheme for memory management , wasted space is due to:

Internal fragmentation

In a system employing a paging scheme for memory management, wasted space is due to:

Internal fragmentation

The Hardware mechanism that enables a device to notify the CPU is called __________

Interrupt

When an external device becomes ready to be serviced by the processor, the device sends this signal to the processor. This signal is called:

Interrupt signal

A table points to routines that handle interrupts is called

Interrupt vector

Which of the following statements is not correct about the device controller of I/O devices?

Is software component of device

Random Access memory:

Is volatile

What is incorrect about contiguous allocation of files ?

It does not cause disk fragmentation

What is incorrect about contiguous allocation of files?

It does not cause disk fragmentation

What is a shell ?

It is a command interpreter

When the currently running process issues a system call for I/O

It is marked blocked and its PCB added to the tail of the device queue associated with the I/O request

What are the main advantages of the microkernel approachto system design?

It is more secure more operations are done in user mode than in kernel

How system clock can be maintained correct time instead of disabling the interrupts

Keeping the disabling time for very short periods

Which of a system call is to allow the file to appear in more than one directory?

LINK

The __________ policy is based on the theory that the best page to remove is the one that has been in The memory the longest

LRU

When making CDs for sale, such as music or software CDs, data is recorded on a master disc by means of a high-intensity laser beam, which burns indentations, called pits, and flat areas, called

Lands

The type of paging where a page is never rolled (or swapped) into memory unless needed is referred to as

Lazy swapper

What algorithm is not a CPU scheduling algorithm

Least Recently Used (LRU)

Which page-replacement algorithm does not suffer from Belady's anomaly?

Least recently used (LRU)

A thread is a __________ process

Light wieght

Which method is used to implement files to keep each file as a linked list of disk blocks?

Linked List Allocation

Which of the following allocation methods, Operating system MS-DOS is implemented?

Linked allocation using FAT

Major thread management tasks do not include

Loading thread-specific program code

Consider a logical address space of eight pages of 1024 words each, mapped onto a physical memory of 32 frames. How many bits are there in the logical address?

Logical address 13 bits

What is Logical address?

Logical address is generated by the CPU and is translated into a physical address by the memory management unit

________ scheduler selects the jobs from the pool of jobs and loads into the ready queue

Long term

__________ selects the process from secondary storage and loads them into memory for execution

Long term scheduler

The degree of Multiprogramming is controlled by

Long-term Scheduler

What is an operating system structure in which the communication between requesting process and responding process is message passing?

MS-DOS

Which ofthe following operating systems is an example of monolithic system?

MS-DOS

Inter process communication can be done through __________

Mails

What are the main differences between operating systems for mainframe computers and personal computers (PC)

Mainframe using for batch job and PC for time sharing

The primary job of the operating system of a computer is to ________

Manage Resources

Which of statement bellow is correct to run a program on a dedicated machine

Manually to load program into memory

Where is the partition table stored?

Master Boot Record (MBR)

The best definition of the term "quantum" is

Maximum time a process may run before being preempted

The scheduler that brings processes into memory and swaps them out on disk as needed is referred to as

Medium-term scheduler

An example of preemptable resources is

Memory

The task of subdividing memory between the OS and processes is performed automatically by the OS and is called

Memory Management

The task of subdividing memory between the OS and processes is performed automatically by the OS and is called:

Memory Management

Which of these statements about the algorithm "Next fit" is true?

Memory Manager starting searching the list of segments from the place where it left off last time

Which of these statements about the algorithm "Next fit" is true?

Memory Manager starting searching the list of segments from the place where it left off last time.

The scheduler that brings processes into memory and swaps them out on disk as needed is referred to as

Memory scheduler

Which scheduler decides the degree of multiprogramming?

Memory scheduler

Which scheduler is responsible for controlling the degree of multiprogramming?

Memory scheduler

Which of the system is used to communicate between thTelephone system

Message system.

Which contains only essential functions of the operating system

Microkernel

Which of the following statements is correct about Shortest Job First

Minimize average waiting time

Which one is high-level language structure to solve the critical-section problem?

Monitor

______ is a high level abstraction over Semaphore

Monitor

MS-DOS is a example of ....

Monolithic system

The second-chance page-replacement algorithm

Moves pages found at the head of a FIFO queue with the referenced bit turned on back to the tail of the queue to avoid replacing them

A computer has 2GB RAM of which the operating system occupies 1GB. The processes are all 450 MB and have the same characteristics. How many percent is CPU utilization when these programs are idle waiting for I/O 20% of the time?

None of the other choices

Which classes of I/O devices that Clock belong to?

None of the other choices

Which is special file?

None of the other choices

Which of following statements about the memory hierarchy is false?

None of the other choices

Which of the following statements about interrupts and trap instructions is incorrect?

None of the other choices

None of the other choices (97,3%)

In the memory-mapped I/O system, in order that CPU communicates with the control registers in the devices, the control register is assigned :

None of the other choices (I/O post number)

Which of these statements about the algorithm "Worst fit" is true?

None of the other choices (largest hole)

Shortest Remaining Time First scheduling is a special case of

None of the others

Which is not the function of a dispatcher?

None of the others

Which is not the property of a signal in UNIX s ystems

None of the others

Which one is not a synchronization problem?

None of the others

Which statement about inverted paging is false?

None of the others

Which of the following conditions that causes the processes to be terminated, when processes have done their work?

Normal exit (voluntary)

Which of the following conditions that causes the processes to be terminated, when the processes executes a system call tell the OS to finish some other process?

Normal exit (voluntary)

When inverted paging is used, there is/are

One global page table sorted by the frame number

How many processes will be affected by deadlock when it happens?

Only some processes make make the request that cannot be granted immediately

The process is the computational environment that includes each of the following except

Operating system

Who is called a supervisor of computer acitvity

Operating system

When a virtual memory system manages memory in fixed length units, which of the following terms correctly represents its unit?

Page

Which of the memory allocation schemes are subject to internal fragmentation?

Paging

Threads can be implemented in each of the following ways except

Parent/child processes

What is interrupt vector?

Part of memory which contains the addresses of interrupt handlers

What is not the technique of implementation for Virtual Memory?

Partition

Which of the following is specified to indicate the directory where the file is located?

Path name

what is Sofware proposal in the solution of Mutual exclusion with Busy waiting?

Peterson's Solution

Consider a logical address space of eight pages of 1024 words each, mapped onto a physical memory of 32 frames. How many bits are there in the physical address

Physical address 15 bits

What is Physical address?

Physical address that refers to an actual physical address in memory

The Best-Fit algorithm for allocating regions of contiguous memory does_________

Pick the closest free region in the entire list.

A CPU may have separate fetch, decode and execute units, so that can carry out three steps of the three instructions in the same time is called:

Pipeline

The hardware mechanism that enables a device to notify the CPU is called _______

Polling

The host repeatedly checks if the controller is busy until it is not. It is in a loop that status register's busy bit becomes clear. This is called _____________ and a mechanism for the hardware controller to notify the CPU that it is ready is called ___________

Polling and Interrupt

An arrival message causes the system to create a new thread to handle this message. This new thread is

Pop-up

An arrival message causes the system to create a new thread to handle this message. This new thread is call

Pop-up

An interrupt that leaves the machine in well-defined state is called a(n)

Precise interrupt

Situations where two or more processes are reading or writing some shared data and the final results depends on the order of usage of the shared data, are called ________

Race conditions

Which of the following instructions should be allowed in user mode

Read the time-of-day clock

What is the purpose of the command interpreter

Reading commands from users

Which of the following process state transitions is illegal?

Ready -> Blocked (waiting)

Which of the following process state transitions is correct, when the scheduler picks a process from the ready queue to run?

Ready -> running

_________ systems are required to complete a critical task within a guaranteed amount of time

Real time

In ______ OS, the response time is very critical

Real-time

Consider the following reference strings {0, 2, 4, 1, 1, 4, 5, 7} {2, 3, 2, 5, 6, 3, 2, 6} The FIFO page replacement algorithm with 3 frames would give lesser number of faults for

Reference string II

Which of the following information bits used by the various page replacement policies indicates if the page has been called lately?

Referenced bit

Which is not a CPU scheduling criterion?

Reliability

________ : A synchronization mechanism that is higher level than hardware-based approaches and provides a counter for solving a variety of synchronization problems.

Semaphore

What are the main purposes of an operating system?

To provide an environment for a computer user to execute programs on computer hardware in a convenient and efficient manner

The dirty bit is used for the purpose of

To reduce the average time required to service page faults

Which of the following reasons why Solaris, Windows XP, and Linux implement multiple locking mechanisms

To support flexibility on the application developers' need

Boundary registers ________

Track page boundaries

Which of the following is not related to the disk access

Transfer Time

The critical section problem is a special case of the mutual exclusion problem.

True

Time between the submission and completion of a processis

Turnaround time

One examples of deadlocks that are not related to a computer- system environment.

Two cars crossing a single-lane bridge from opposite directions

All deadlocks involve conflicting needs for resources by

Two or more processes

Linux and are often used as operating systems on supercomputers, mainframes, and servers.

UNIX

UMA stands for _______________

Uniform memory access

One of the most important innovations of demand paging was that it made feasible

Virtual memory.

Which of the following statements is true?

Volatile storage refers to main and cache memory and is very fast

Page sharing ________

does not allow modifiable procedures from being used by more than one process at the same time

Short-term Scheduler may execute for

only few milliseconds

In the running state

only the process which has control of the processor is found

Locking a page in memory is often called

pinning

Which of the following is not a condition necessary for deadlock to exist?

preemption condition

Under    ________ scheduling, processes can be interrupted whether they have completed their current task or not

preemptive

Which of a system call is to allow the system announce that the file is coming and set some of the attributes?

CREATE

The principle of locality of reference justifies the use of ________

Cache memory

Which of the following statement is correct about a disadvantage of memory-mapped I/O?

Caching a device control register would be disastrous

What is true about non-preemptable resources? (non preemptable)

Can share among processes

CPU Scheduling algorithms are used for

Choosing the next process to run from the PCBs in the ready list

In a directed graph used to model deadlock, processes are represented using

Circular

In one of the deadlock prevention methods, impose a total ordering of all resource types, and require that each process requests resources in an increasing order of enumeration. This voilates the _______________ condition of deadlock

Circular Wait

_________is when each process involved in the impasse is waiting for another to voluntarily release the resource so that at least one wil l be able to continue on.

Circular-wait condition

Which of a system call is to allow the system free up internal table space?

In an operating system a utility which lets the users issue and execute commands from the keyboard is called:

Command Interpreter

Primary operating system design issues include the following except

Compact memory representation

When we have a message-passing scheme between processes P and Q as: send (P, message ) and receive (Q,message), this has the following property:

The link may be unidirectional or bidirectional

Very long Page tables

Internet is

WAN

Which is the correct description of transitions between process states below? (see picture)

1: Process blocks for input; 2: Input becomes available; 3: Scheduler picks this process; 4: Scheduler picks another process

Suppose that the following processes arrive for execution at following. Turnaround time of the processes in order from P1 to P3 by SJF algorithm

27, 17, 9

In which of the following context switching never takes place?

SJF

Which is not a preemptive scheduling?

SJF

Which of the process scheduling algorithm do you expect to produce the smallest average waiting time

SJF

Which of the scheduling algorithm gives the minimum average waiting time for a given set of processes?

SJF

Which cannot be able to solve the race condition?

TSL

Which of the following statements is a hardware solution to the critical region problem?

TSL

The major problem with priority scheduling algorithm is _________

Takes large turnaround time

A page fault means that we referenced a page

That was not in main memory

What is asynchronous transfer in principles of I/O software?

The CPU starts the transfer and goes off to do something else until the interrupt arrives

Semaphores are only useful for solving critical section problems, and not other synchronization problems.

False

Which of the following is not a path name for the file /etc/passwd

None of the above

Race condition results for the following

competing processes

Most deadlocks in operating systems develop because of the normal contention for _________

dedicated resources

If a deadlocked system, the processes can

do nothing

Round robin scheduling is essentially the preemptive version of ________

FCFS

Which is a non-preemptive scheduling?

FCFS

Round robin scheduling is essentially the preemptive version of ________

FIFO

_________ page replacement alogorithm suffers from Belady's anamoly.

FIFO

Which is not the bene?t of using threads?

Fairness

What is the smallest value of X for which this is a safe state?

Critical Region (Section) concept used in interprocess communication is:

A part of the program where the shared memory is accessed

Which of the following statements is incorrect about user mode and kernel mode?

None of the above

A multiprogramming OS allows more than one process at a time to be loaded into the primary memory, but limits processes to one thread each.

False

Device drivers implement the device independent aspects of device management.

False

The time taken to bring the desired track/cylinder under the head is _________

Seek time

Time for the disk arm to move to the desired cylinder is

Seek time

Which of the following is crucial time while accessing data on the disk?

Seek time

Which of the following memory allocation scheme suffers from External fragmentation

Segmentation

Which of the memory allocation schemes are subject to external fragmentation?

Segmentation

C-SCAN is also known as ________

Circular scan

What is the characteristic of deadlocked systems

Circular wait

Memory is usually word-addressable, to match the CPU word size.

False

New synchronization methods such as AND, Events, and Monitors enable solutions to problems that cannot be solved solely with semaphores.

False

Placing mailboxes in user space is preferable to placing them in system space.

False

Programmers need to know device details in order to use a device.

False

Which statement about process is false

A program is a process in execution

What is the purpose of system calls

Allow users to request services of the operating system

The special files are:

Both a and b

Which page-replacement algorithm suffers from Belady's anomaly?

Clock

Which statement about hard and soft links is false

Hard links can point to ?les in other disk partitions

Which is the advantage of multiprocessor systems?

Increased reliability

Which of the following disk scheduling techniques has a drawback of starvation ?

SSTF

Which of the following is not correct about hard links and symbolic links?

Hard links can point to files on other machines

The mode bit is implemented in

Hardware

How many percent of the CPU time is wasted, when a computer system has enough room to hold two program and these programs are idle waiting for I/O 10% of the time?

1 %

Which of the following are CPU Scheduling Criteria?

(1) and (2)

The operating system of a computer serves as a software interface between the user and the ________

Hardware

Suppose that the following processes arrive for execution at following. Waiting time of the processes by FCFS algorithm are

0, 12, 19

Suppose that the following processes arrive for execution at following. Response time of the processes by FCFS algorithm are

0, 12, 22

Suppose that the following processes arrive for execution at following. Response time of the processes in order from P1 to P3 by SJF algorithm are

0, 2, 0

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 FIFO replacement algorithms, assuming six frames? Remember all frames are initially empty, so your ?rst unique pages will all cost one fault each.

Show the sequence of frames put into main memory with following reference string : 5 4 8 2 7 4 5 9 1 8 7 4 5 2 7How many page faults if using 3 available frames and the OPT algorithm.

Consider a swapping system in which the memory consists of the following hole sizes: 10 K, 4 K, 20 K, 15 K, 9 K. Assume first fit algorithm is used. Which holes are taken for successive segment requests of 8 K, 12 K, 10 K?

10 K, 20 K, 15 K

Consider a disk with a mean see k time of 8 msec, a rotational rate of 12,000 rpm, and 524,288 bytes per track. What is the average access time for block sizes of 8 KB?

10.578 msec

Suppose that the following jobs arrive as indicated for scheduling and execution on a single CPU. calculate the average job waiting time using Round Robin RR (quantum = 4) scheduling for these jobs

10.6 ms

The time to read or write a 32-bit memory word is 10 nsec . Assume the total holes take one ?fth of the 256 MB memory. What is the time needed to eliminate holes by compaction?

1073.74 msec

Show the sequence of frames put into main memory with following reference string : 5 4 8 2 7 4 5 9 1 8 7 4 5 2 7How many page faults if using 5 available frames and the FIFO algorithm

An OS uses the elevator algorithm to schedule the disk-arm. I?O requests are currently pending for blocks on tracks 1, 3, 8, 11, 15, and 16. The disk arm is currently at track 9 and moving upwards. In what order will these requests be handled?

11, 15, 16, 8, 3, 1

Suppose that the following processes arrive for execution at following. Turnaround time of the processes by FCFS algorithm

12, 22, 28

Consider the following set of processes, with the length of the CPU burst given in milliseconds:The processes are assumed to have arrived in the order P1, P2, P3, P4, P5, all at time 0.What is the average turnaround time of these processes using the scheduling algorithms nonpreemptive priority (a small priority number implies a higher priority)

12.0

The computer provides the user with virtual address space of 2^24 words. Pages of size 4096 (2^12) words. If the hexadecimal virtual address is 123456, the page number in hexadecimal would be

123

Suppose a virtual address space of 2^28 words and the page size is 2^12 words. If the virtual address is 1234567 in Hexadecimal , what would be the page number in Hexadecimal?

1234

An OS uses a paging system with 1Kbyte pages. A given process uses a virtual address space of 128K and is assigned 16K of physical memory. How many entries does its page table contain?

128

Show the sequence of frames put into main memory with following reference string : 5 4 8 2 7 4 5 9 1 8 7 4 5 2 7How many page faults if using 4 available frames and the LRU algorithm

13.4

Show the sequence of frames put into main memory with following reference string : 5 4 8 2 7 4 5 9 1 8 7 4 5 2 7How many page faults if using 3 available frames and the FIFO algorithm

Suppose that the following processes arrive for execution at following. Waiting time of the processes in order from P1 to P3 by SJF algorithm are

15, 5, 0

If there are 64 frames, and the frame size is 1024 words, the length of physical address is

16 bits

In paging system where page size is 4096 words, and the available physical memory is equal to 2^24 = 16 M words, the length of physical address is equal to

16 bits

If there are 64 pages and the page size is 2048 words, what is the length of logical address?

17 bits

If there are 64 pages, and the page size is 2048 words, the length of logical address is

17 bits

In demand-paged system where page size is 2048 words, and the available physical memory is equal to 2^17=128K words, the length of the physical address is equal to :

17 bits

In demand-paged system where page size is 1024 words, and the available physical memory is equal to 2^18=256 K words, the length of the physical address is equal to

18 bits

How much cylinder skew is needed for a 5400- RPM (rotate per minute) disk with the track-to-track seek time of 1 msec? The disk has 200 sectors of 512 bytes on each track.

18 sectors

How many is virtual memory bigger physical memory

How many ways is Thread implemented?

There are ___________entries per page in the Page table.

How many categories can be the I/O devices roughly divided?

2 (block devices and character devices)

A machine with 512 (2^9) MB memory has a 32-bit memory word. The frame size is 128 (2^7) words. How many bits are used to indicate the frame number ?

20 bits

A computer provides the user with virtual address space of 2^32 words. Pages of size 4096 (2^12) words. If the hexadecimal virtual address is 23456789, the page number in hexadecimal would be:

23456

A disc queue with requests for I?O to blocks on cylinders 98, 183, 37, 122, 14, 124, 65, 67 If the head is initially at 53rd cylinder, what will be the total number of cylinders traversed if we are using SSTF disc scheduling algorithm

236

A disc queue with requests for I?O to blocks on cylinders 98, 183, 37, 122, 14, 124, 65, 67 If the head is presently at 53rd cylinder, what will be the total number of cylinders traversed if we are using SCAN disc scheduling algorithm

252

Which of the following page-replacement algorithms is perfect according to their page-fault rate

269355. FIFO replacement

Assuming that it takes 10 nsec to copy a byte, how much time does it take to completely rewrite the screen of a 1200 x 800 pixel graphics with 24- bit color?

28.8 msec

Suppose that the following processes arrive for execution at following. Turnaround time of the processes in order from P1 to P3 by Round Robin algorithm with quantum time is 3 are

31, 28, 18

If the Disk head is located initially at 32, find the number of disk moves required with FCFS if the disk queue of I/O blocks requests are 98,37,14,124,65,67

321

If the Disk head is located initially at 32, find the number of disk moves required with FCFS if the disk queues of I¤O blocks requests are 98,37,14,124,65,67

321

A computer provides the user with virtual address space of 2^28 words. Pages of size 4096 (2^12) words. If the hexadecimal virtual address is 3456789, the page number in hexadecimal would be

3456

A computer provides the user with virtual address space of 2^32 words. Pages of size 4096 (2^12) words. Jf the hexadecimal virtual address is 34567890, the page number in hexadecimal would be

34567

355

A disc queue with requests for I?O to blocks on cylinders. 98, 183, 37, 122, 14, 124, 65, 67 If the head is presently at 53rd cylinder, what will be the total number of cylinders traversed if we are using C-SCAN disc scheduling algorithm

382

39.4 msec

Which is the maximum number of partition that most disks can be divided up?

A system with a 32-bit virtual address. It uses the ?rst 20 bits to indicate the page number. Each table entry takes 4 bytes . What is the size of the page table?

4 MB

Consider a computer system that has cache memory, main memory (RAM) and disk, and OS uses virtual memory. It takes 2 nsec to access a byte from the cache. 20 nsec to access a byte from RAM. and 10 msec to access a block of 1000 bytes from the disk. If a book has 1000 pages, each with 50 lines of 80 characters each. How long it will take to electronically scan the textfor the case of the master copy being in each of the level as one proceeds down the memory hierarchy (from inboard memory to offline storage)?

4 msec. 40 msec. 20 sec

Imagine that a certain modem can read 7,000 characters per second and that the time to read a character to the modem register is so short it can be ignored. If to run this modem using interrupt-driven I/O and each character read requires an interrupt that takes 10 usee all-in to service. How many percent of the CPU does the interrupt overhead cost?

4% of the CPU

In multilevel queue scheduling (CPU scheduling) arrange the following in the order lowest to highest priority.

4, 2, 1, 3

A disk use 24-bit disk addresses . What is the percentage of disk space that must be free so that the free list uses less space than the bit map?

4.167%

Assuming that it takes 10 nsec to copy a byte, how much time, does it take to completely rewrite the screen of a 200 character x 20 line text mode memory-mapped screen?

40 micro-sec

Rearrange the layers in I/O software starting at the bottom

43251

Suppose that the following jobs arrive as indicated for scheduling and execution on a single CPU. calculate the average job waiting time using preemptive Shortest Remaining Time First (SRTF) scheduling for these jobs

5.8 ms

A ?le system use s 24-bit disk addresses with the block size 4 KB. What is the maximum partition size?

64 GB

640

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 LRU replacement algorithms, assuming six frames? Remember all frames are initially empty, so your ?rst unique pages will all cost one fault each.

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 Optimal replacement algorithms, assuming six frames? Remember all frames are initially empty, so your ?rst unique pages will all cost one fault each

7.0

Assume the Memory Manager receives a request for a block of 200. When the best-fit algorithm is used, is the beginning address of the hole granted by the Memory Manager. Beginning Address of Hole Hole Size

7600

Suppose that the following jobs arrive as indicated for scheduling and execution on a single CPU. calculate the average job waiting time using non-preemptive SJF scheduling for these jobs.

8.6 ms

If all page frames are initially empty, and a process is allocated 3 page frames in real memory and references its pages in the order 1 2 3 2 4 5 2 3 2 4 1 and the page replacement is FIFO, the total number of page faults caused by the process will be __________

Suppose that the following jobs arrive as indicated for scheduling and execution on a single CPU. calculate the average job waiting time using (preemptive) PRIORITY scheduling for these jobs

9.0 ms

9.2

Suppose that the following jobs arrive as indicated for scheduling and execution on a single CPU. calculate the average job waiting time using FCFS scheduling for these jobs

9.8 ms

Consider a swapping system in which the memory consists of the following hole sizes: 10K, 4K, 20K, 15K, 9K. Assume best fit algorithm is used. Which holes are taken for successive segment requests of 8K, 12K, 10K?

9K, 15K, 10K

Which of the following statements is true to explain the purpose of the checkpoint mechanism

A checkpoint log record indicates that a log record and its modified data has been has been not yet written to stable storage

A file is generally defined to be:

A collection of similar records

File is generally defined to be:

A collection of similar records

Which of the following statements is incorrect?

A hard drive is an example of a character-oriented I/O device

Under what circumstances do page faults occur?

A page fault occurs when an access to a page that has not been brought into main memory takes place

Critical Region (Section) concept used in interprocess communication is:

A part of shared memory

A "critical section" of code is

A section of the program that is susceptible to race conditions, unless mutual exclusion is enforced

Deadlock definition:

A set of processes is deadlocked if each process in the set is waiting for an event that only another process in the set can cause. What does event mean?

Explain the concept of transaction atomicity

A transaction is a series of read and write operations upon some data  followed by a commit operation

The language ofthe CPU is known as its

Instruction set

In which environment is preemption essential?

Interactive

Which of the following instructions should be allowed only in kernel mode?

ADD of two numbers

Where is the position of the operating system in computer system:

Above the hardware and under the user interface program

The actual location in main memory is called a(n):

Absolute address

Which of the following statements is incorrect about timesharing and multiprogramming systems?

Al l multiprogramming systems are timesharing systems

The following statements about process control blocks are true, except

All resources the process has used during it's execution

Scheduling is ________

Allowing jobs to use the processor

Multiprocessing ________

Allows the same computer to have the multiple processors

When inverted paging is used, we cannot do binary searches on the one global page since

Although the entries are sorted by frame number, we are looking for process-id and matching virtual page number

Why do some systems store the operating system in ?rmware, and others on disk?

None hard disk on system

Virtual memory is __________

An illusion of extremely large main memory

Which of the following actions generates an external interrupt?

An input/output operation is completed.

Multiprogramming systems

Are easier to develop than single programming systems

Allocate the smallest hole that is big enough , is which type of fit in dynamic storage allocation problem.

Best fit

In terms of disk storage efficiency, the method of "Backing up pages dynamically" in comparison with the method of "Paging to a static swap area" is

Better

Semaphores that are initialized to 1 and used for two or more processes to ensure only one can enter its critical section at the same time are called:

Binary semaphores

What kind of I/O devices that disks and tapes belong to?

Block-oriented devices

The state of a process after it encounters an I/O instruction is __________

Blocked/Waiting

Disk can be divided up into one or more partitions. The first block of every partition is called:

Boot block

Monitors implement ________ between threads of execution

Both (1) and (2)

Most CPUs have the following type interrupt request

Both (1) and (2)

The following are the criteria for CPU scheduling algorithm evaluation

Both (1) and (2)

Which of the following is?are true about multitasking?

Both (1) and (2)

Which of the following statements are false?

Both (1) and (2)

What are volatile devices

Both (2) and (3)

Which of the following are Scheduling algorithms

Both 1 and 2

Which of the following is a method to keep track of memory usages?

Both Memory Management with Bit Maps and Memory Management with Linked Lists

Which statement about user-level threads and kernel threads is correct?

Both User-level and kernel threads can write into each other's memory space

Which is special file?

Both character special file and block special file

Which statement about user-level threads and kernel threads is false

Both user- level and kernel threads share their registers and stack

Which is not a CPU scheduling criterion?

Burst time

Which of the following is not a CPU scheduling criterion?

Burst time

Which is not the requirement of a solution to the critical-section problem

Busy Waiting

_________ does the job of allocating a process to the processor

Dispatcher

The page size that is too small wil l generate

Very long Page tables

In which disc scheduling algorithm the head traverses till one end then returns directly to the other end before encountering any other cylinder.

C-SCAN

Which of the following I/O software device layers is done by user-level software?

Converting binary integers to ASCII for printing

Which of the following I/O software do Device drivers do?

Converting binary integers to ASCII for printing

It is not the layer of the Operating system

Critcal Section

The section of code which accesses shared variables is called as __________.

Critical section

In a directed graph used to model deadlock, ______represents deadlock.

Cycle

________________ gives control of the CPU to the process selected by the short term Scheduler

Dispatcher

Which of a system call is to allow the system free up disk space?

DELETE

The term__________a specialized instruction set.

DMA characterizes a system configuration that includes an I/O module that is a separate processor with

Which of the following statements is not correct about DMA ?

DMA controller is usually faster than CPU

Which of the following statements is incorrect about I/O using DMA?

DMA is software solution to speed up data transfer between I/O device and memory

What is a "stripping" in RAID?

Distributing data over multiple drives

A process said to be in ___________ state if it was waiting for an event that will never occur

Dead lock

The permanent blocking of a set of processes that compete for system resources is called

Deadlock

_________ is the situation in which a process is waiting on another process,which is also waiting on another process ... which is waiting on the first process. None of the processes involved in this circular wait are making progress

Deadlock

What are the major activities of an operating system in memory management?

Decide which processes are to be loaded into memory when memory space becomes available

Which of the following is not advantage of multiprogramming?

Decreased operating system overhead

The mechanism that bring a page into memory only when it is needed is called _____________

Demand Paging

Virtual Memory is commonly implemented by __________

Demand Paging

In which of the four I/O software layers is computing the track, sector, and head for a disk read done

Device drivers

Which of the following statements is not correct about "device independence"?

Device independence requires all programmers to deal with different devices directl

Device Driver is normally written by:

Device's Manufacturer

Device Driver is usually written by:

Device's Manufacturer

Which statement about contiguous allocation is incorrect?

Difficult to implement

In general, which is the best technique for I/O Data transfer?

Direct Memory Access

In the ___________ method of data transfer, the participation of the processor is eliminated during data transfer

Direct Memory Access

Which of the following instructions should be allowed only in kernel mode?

Disable all interrupts

Which of the following instructions should be allowed only in kernel mode?

Disable all interrupts 1

In a single processor system, mutual exclusion can be guaranteed by:

Disabling interrupts

Which of the following gives control of the CPU to the process selected by short term scheduler?

Dispatcher

Routine is not loaded until it is called. All routines are kept on disk in a relocatable load format. The main program is loaded into memory & is executed. This type of loading is called _________

Dynamic linking

Multiprogramming systems ________

Execute more jobs in the same time

CPU burst distribution is generally characterized as

Exponential or hyper-exponential

In which of the following scheduling schemes does context switching never take place

FCF

If the time quantum is very big in round robin CPU scheduling algorithm, then it acts as

FCFS

If the time quantum is very large, a RR (Round-Robin) scheduling is the same as

FCFS

In which disc scheduling algorithm the head traverses to the first cylinder encountered in the given order

FCFS

Non-preemptive scheduling strategies that commonly rely on process?thread execution time include the following except

FCFS

A________is a group of related records that contains information to be used by specific application programs to generate reports.

File

A table in main memory storing linked list allocation of disk blocks is called:

File Allocation Table

The services provided by an operating system

File manipulations

Many computer users and some operating systems call subdirectories

Files

Which of the following not a Scheduling algorithm

First come last serve

In terms of speed the best method of Dynamic Storage-Allocation is:

First fit

Which page-replacement algorithm suffers from Belady's anomaly?

First in First out (FIFO)

What system calls have to be executed by a command interpreter or shell in order to start a new process?

Fork followed by exec

In memory management , a technique called as paging, physical memory is broken into fixed-sized blocks called ___________

Frames

What are the major activities of an operating system in regard to secondary-storage management?.

Free-space management

The two basic types of processor registers are:

General and special registers

Round robin scheduling ________

Gives each task the same chance at the processor

Where can Embedded Operating Systems mostly be found?

Handheld Computer

"A process may hold allocated resources while awaiting assignment of other resources" best describes which one of the following conditions?

Hold and wait

____________allows a resource to be held by a process as long as it is needed.

Hold and wait condition

______allows a resource to be held by a process as long as it is needed

Hold and wait condition

Which is the fastest bus in the IBM PC computer?

ISA (Industry Standard Architecture)

A possibility of deadlock can occur:

If a system is in unsafe state

Which is a wrong statement about the quantum used in Round Robin algorithm ?

None of the above

Thrashing ________

Implies excessive page I/O

Which statement is false

In a multithreaded environment, the unit of resource ownership and scheduling/execution is thread

Which statement about memory systems is untrue?

In swapping systems, the absolute module and allocated primary memory space differ in size

What is not correct about system calls

In terms of performance, using system calls is better than using procedure calls

In order to implement mutual exclusion on a critical resource for competing processes, only one program at a time should be allowed:

In the critical region of the program

Which of the following statements are true about computers with memory-mapped I?O?

In theory, computers with memory-mapped I?O do not need explicit I?O instructions

The i-nodes are used in which of the following allocation methods the i-nodes use

Indexed allocation

Which of the following allocation methods the i-nodes use?

Indexed allocation

The collection of processes on the disk that is waiting to be brought into memory for execution forms the ___________

Input queue

Which of these scheduling algorithms allows a process to move up and down between queues?

Multilevel feedback queue scheduling

Which of the memory allocation schemes are subject to internal fragmentation?

Multiple Contiguous Fixed Partitions

Why spinlocks, mutexes used for

Multiple locking mechanisms

Which technique was introduced because a single job could not keep both the CPU and the I/O devices busy?

Multiprogramming

What is adaptive mutexes

Mutex implemented with a spin lock on multiprocessor machines

"Only one process may use a resource at a time" best describes which one of the following?

Mutual Exclusion

_________is the act of allowing only one process to have access to a dedicated resource

Mutual-exclusion condition (Mutual exclusion condition)

Which is not an example of a resource that is commonly time-multiplexed?

Network interface

"No resource can be forcibly removed from a process holding it" best describes which one of the following conditions?

No preemption

Which deadlock condition does "Take resources away" attack?

No preemption

Which conditions of mutual exclusion does the Lock Variables (Software proposal) violate?

No two processes simultaneously in critical region

FCFS scheduling is ________

Non Preemptive Scheduling

FIFO scheduling is ________

Non Preemptive Scheduling

Forcible removal of a resource from a process is possible through _____

Preemption

Which is not the necessary condition of a deadlock?

Preemption

Which of the following is not a condition necessary for deadlock to exist?

Preemption condition

Which of the statement de?ne the preemptive scheduling?

Preemptive scheduling allows a process to be interrupted in the midst of its execution, taking the CPU away and allocating it to another process

Which of the following information bits in the entry of page table is false?

Present/absent bit

Which of the following information bits in the entry of page table is used to indicate Page Fault?

Present/absent bit

Which is not the state of the process

Privileged

A program at the time of executing is called ________

Process

Information about a process is maintained in a _________

Process Control Block

Process State is a part of

Process Control block

The thread library schedules user level threads to run on an available Light wait process, this scheme is known as ______________

Process Local Scheduling

Which of the following is an Operating System component?

Process Management

System calls to allocate and free memory belongs to which of the operating system service category below

Process control

Each process is represented in operating system by

Process control block

The kernel keeps track of the state of each task by using a data structure called __

Process control block

Which of the following is appropriate to determine program size and create page table?

Process creation

A binary program may also be known as each of the following except

Process program

What is context switching?

Processor switches execution control from one process to another

The four main structural elements of a computer system are:

Processor, Main Memory, I/O Modules, System Bus

Which of these is not a part of the process scheduler?

Program Control

A Control/Status register that contains the address of the next instruction to be fetched is called the:

Program Counter (PC)

Which of special register contains the condition code bits, the CPU priority, the mode bit and other control bits?

Program Status Word (PSW)

The problem of thrashing is effected scientifically by ________

Program structure

The I/O technique where the processor busy waits for an I/O operation to complete is called:

Programmed I/O

The general role of an operating system is to:

Provide a set of services to system users

What is not a main function of an operating system?

Provide user interfaces

Which of the following programming techniques and structures are "good" for a demand-paged environment?

Pure code and stack

Maximum time a process may run before being preempted is

Quantum

Which of a system call is to allow the system fetch the attributes and list of disk addresses into main memory for rapid access on later call?

RENAME

_______is a specialized WRITE command for existing data files that allows for appending records or for rewriting selected records in their original place in the file.

REWRITE

is a specialized WRITE command for existing data files that allows for appending records or for rewriting selected records in their original place in the file.

REWRITE

Which is a preemptive scheduling?

Which scheduling algorithm is better for an interactive system?

Which scheduling policy is most suitable for a time shared operating systems?

When two or more processes attempt to access the same resource a _________ occurs

Race condition

What is the weakness of the Banker's algorithm?

Requiring that processes state their maximum needs in advance

Time for a user to get a reaction to his/her input is

Response time

Which is not a goal of a scheduling algorithm for batch systems ?

Response time

What is the main characteristic of embedded operating system

Restriction of memory size, speed of CPU, screen size, powers

The aspect of disk performance that represents the time it takes to position the head a the desired track is known as

Rotational delay

Time for the disk to rotate to the desired sector is

Rotational latency

Which of the following is a preemptive scheduling algorithm

Round Robin

Which of the following is strictly preemptive?

Round Robin

In interactive environments such as time-sharing systems, the primary requirement is to provide reasonably good response time and in general, to share system resources equitably. In such situations, the scheduling algorithm that is most popularly applied is ________

Round Robin Scheduling

In ________ scheduling technique, each process gets a small quantity of time and then it is preempted and the next process gets to run

Round robin

In UNIX if multiple threads have the same priority, the scheduler uses _______

Round robin queue

Replace the page that will not be used for the longest period of time. This principle is adopted by ____________

Round robin scheduling algorithm

The scheduling strategy where each process in the queue is given a certain amount of time, in turn, to execute and then returned to the queue, unless blocked is referred to as:

Round-Robi

In which disc scheduling algorithm the head traverses to the extreme end cylinders

SCAN

Which of the following is not a CPU scheduling algorithm?

SCAN

In which disc scheduling algorithm the head traverses to the nearest available cylinder

SSTF

A set of resources' allocations such that the system can allocate resources to each process in some order, and still avoid a deadlock is called ________

Safe state

The First-Fit algorithm for allocating regions of contiguous memory does_________

Scan memory region list from start for first fit

What is the main dif?culty that a programmer must overcome in writing an operating system for a real-time environment?

Scheduling schemes don't allow response time to exceed the time constraint

The size of single unit of allocation on disk is called ____

Sector size

The time taken by the disk arm to locate the specific address of a sector for getting information is called __________

Seek Time

Which of the following synchronization mechanisms does not rely on busy-waiting ?

Semaphores

Which is not a solution to the critical-region problem?

Shared memory

Which is not able to solve the race condition?

Shared memory

When a process creates a new process using the fork() operation, which of the following state is shared between the parent process and the child process?

Shared memory segments

When a process is created using fork(). what is shared between parent process and child process

Shared memory segments

In an operating system a utility which reads commands from a terminal is called:

Shell

An optimal scheduling algorithm in terms of minimizing the average waiting time of a given set of processes is ________

Shorest job - first scheduling algorithm

Under multiprogramming, turnaround time for short jobs is usually ________ and that for long jobs is slightly ___________

Shortened; Lengthened

Suppose that the following jobs arrive as indicated for scheduling and execution on a single CPU. What scheduling algorithm has the smallest the average job waiting time for these jobs.

Shortest Remaining Time First (SRTF)

What algorithm is not a Page Replacement Algorithm

Shortest Remaining Time Next (SRTN)

If a new process arrives with CPU burst time less than remaining CPU burst time of current executing process, preempt. This scheduling algorithm is known as ____________

Shortest-Job-First

Which of the following statement is correct about a disadvantage of memory-mapped I/O?

Since the control registers of devices are mapped into the memory space, device drivers can be written in C

System calls are generally invoked by using

Software interrupt

adaptive mutexes are used in _________

Solaris 2

What is the purpose of system programs?

Solving the problems of operating system

What is the correct approach with the "Mutual Exclusion condition" to prevent Deadlock?

Spool everything

is when, in modern printing systems, a disk accepts output from several users and acts as a temporary storage area for all output until the printer is ready to accept it

Spooling

In a directed graph used to model deadlock, resources are represented using

Squares.

Which of the following cannot be shared among different threads of a process?

Stack

What for is Boot manager?

Startup system

A major problem with priority scheduling is _________

Starvation

Which is not the necessary condition for a deadlock?

Starvation

Stable storage refers to

Storage devices in which information residing is never lost

Which of the following is not special file?

Stream special file

Which statement is true ?

Suspending a process involves suspending all threads of the process since all threads share the same address space

Medium term scheduler is based on

Swap in, swap out

The removal of process from active contention of CPU and reintroduce them into memory later is known as ____________

Swapping

Which of the following is correct about symbolic links?

Symbolic links can point to files in the network

Semaphore can be used for solving __________

Synchronization

The process related to process control, file management, device management, information about system and communication that is requested by any higher level language can be performed by __________

System Call

What is the purpose of system calls?

System calls allow admin-level processes to request services of the operating system

Which of the events that causes the processes to be created, when an operation system is booted?

System initialization

What is the main advantage of the layered approach to system design?

System is easier modify

What is the name of the software which deals with the running of the actual computer and not with the programming problems?

System program

Which is a hardware solution to the critical-section problem?

TestAndSet

Assume the following events and actions take place. The following statement is true. Event Action 1 P1 requests and is allocated R1. P1 requests and is allocated R1 2 P2 requests and is allocated R2 3 P3 requests and is allocated R3 4 P1 requests R2. 5 P2 requests R3. 6 P3 requests R1.

There is no deadlock

Which of the following is not a step in the boot process?

The antivirus program checks all files for viruses.

In an OS that uses a trap to make a system call

The application process executes kernel

What is the correct approach of the driver of dedicated devices with requesting device that is busy to solve deadlock using Ostrich algorithm?

The device driver decides blocking and returning an error code

Deadlock definition: A set of processes is deadlocked if each process in the set is waiting for an event that only another process in the set can cause. What does event mean?

The event is release of a currently held resource

The page table for each process maintains:

The frame location for each page of the process

If in a resource-allocation graph, each resource type has exactly one instance, which of the following indicate a deadlock situation?

The graph has at least one cycle.

An operating system is distinguished from other system software by each of the following except

The hardware resource abstractions it provides are convenient, but their use by applications is generally optional

With paging, the internal fragmentation is possible when:

The last page of the job is less than maximum page size

The system is said to be in an unsafe state if

The operating system cannot guarantee that all current processes can complete their work

With dynamic address relocation, the limit register contains

The size of the address space

The solution to Critical Section Problem is : Mutual Exclusion, Progress and Bounded Waiting

The statement is true

What are the major activities of an operating system in regard to process management?

The suspension and resumption of processes

In an interactive system the turnaround time is

The time from when the command is submitted, until the time the results of the command have been returned to the user

In a multi-process system, at any moment every process is in one of three states : running, ready, or blocked. What does the transition occur when the scheduler decides to run the process

The transition of being selected takes the process from ready to running

In a multi-process system, at any moment every process is in one of three states : running, ready, or blocked. What does the transition occur when the process needs to wait for input or for a semaphore or other synchonization condition

The transition of blocking takes the process from running to blocked

In a multi-process system, at any moment every process is in one of three states : running, ready, or blocked. What does the transition occur when a preemptive scheduler decides to run another process

The transition of preemption takes the process from running to ready

In a multi-process system, at any moment every process is in one of three states : running, ready, or blocked. What does the transition occur when the event for which the process is waiting completes: either the input completes, or the semaphore is released ?

The transition of unblocking takes the process from blocked to running

CPU performance is measured through ________

Throughput

The number of processes completed per unit time is known as __________

Throughput

The performance of round robin algorithm depends on

Time Quantum

The technique, for sharing the time of a computer among several jobs, which switches jobs so rapidly such that each job appears to have the computer to itself, is called ________

Time Sharing

The best definition of the term "turnaround time" is

Time between the submission and completion of a process

The best definition of the term "respond time" is

Time for a user to get a reaction to his?her input

The best definition of the term "seek time" is

Time for the disk arm to move to the desired cylinder

The best definition of the term "rotational latency" is

Time for the disk to rotate to the desired sector

Round robin algorithm is suitable for which type of systems?

Time sharing

Which method is used to prevent the communication deadlock?

Timeouts

How does the distinction between kernel mode and user mode function?

To Access hardware device using Kernel mode

Which is not a function of device drivers?

To accept abstract read and write request from device independent software above it and see that they are curried out

The basic idea behind the microkernel design is:

To archive high reliability by splitting operating system up into small, well-defined modules

What advantage is there in having different time-quantum sizes on different levels of a multilevel queueing system?

To make more efficient use of the computer

The primary purpose of an operating system is ____

To make the most efficient use of the computer hardware

Some early computers protected the operating system by placing it in a memory partition that could not be modi?ed by either the user job or the operating system itself. What is dif?culty that you think could arise with such a scheme

To protect data in memory

_________ is a high speed cache used to hold recently referenced page table entries a part of paged virtual memory

Translation Lookaside buffer

Which of the following file structure is used for file system in Window?

Tree

A major distinction between events and semaphores is that if no thread is waiting when a signal is raised, the result of the signal() operation is not save and its occurrence will have no effect.

True

A monitor forces a process to wait if another process is currently executing one of the monitor's member functions.

True

Working set model is

Used for ?nding the minimum numb er of frames necessary for a job, so that jobs can run without "thrashing"

Real time systems are ________

Used for monitoring events as they occur

Some CPUs provide for two modes of operation. What are they?

User mode and Kernel mode

What is the effect of allowing two entries in a page table to point to the same page frame in memory?

Users share code and data

Show the sequence of frames put into main memory with following reference string : 5 4 8 2 7 4 5 9 1 8 7 4 5 2 7Which gives the lowest fault rate on this string?

Using 3 available frames and the OPT algorithm

With the round robin CPU scheduling in a time-shared system ________

Using extremely small time slices degenerate in to last in first out algorithm

Timers could be used to compute the current time. Provide a short description of how this could be accomplished

Using timer interrupts

The purpose of multiprogramming is to

Utilize CPU better

What is the characteristic of the first generation of operating system?

Vacuum tubes, plug boards

Which one of the following is true for a CPU having a single interrupt request line and a single interrupt grant line?

Vectored interrupts are not possible but multiple interrupting devices are possible

What is true about preemptable resources?

Will cause the process to fail if taken away

Which of the following is not correct about user-level threads ?

With user-level threads, customized scheduling algorithms cannot be implemented

_________ allocates the largest hole (free fragmant) available in the memory

Worst Fit

Which of the following statements is incorrect about Translation Look-aside Buffer (TLB)?

[C]

What is the method to keep track of memory usages?

a and b

A process is another name for

a job

In a multi-process system, at any moment every process is in one of three states: running, ready, or blocked. The transition of preemption takes the process from running to ready. It occurs when ________

a preemptive scheduler decides to run another process

The dispatcher

actually schedules the task to the processor

Code inside a critical section should ________

all of the above

Scheduling is

allowing job to use the processor

Demand paged memory allocation

allows the virtual address space to be independent of the physical memory

An interrupt is the same as a trap in that they both

cause the processor to switch to supervisor mode and branch to a handler

A well-known Real-Time operating system is:

e-COS

The SJF algorithm

executes first the job with the least processor needs

Why Solaris, Windows XP, and Linux implement multiple locking mechanisms

for application developer's needs

Which system call can you use to create a new process?

fork

A binary semaphore

has the values one or zero

A process is starved

if it is permanently waiting for a resource

A scheduling algorithm is fair

if no process faces starvation

A disadvantage of preemptive scheduling is ________

increased overhead

A thread

is a lightweight process where the context switching is low

A critical region

is a piece of code which only one process executes at a time

Assume that there are four queues in a multilevel queue scheduling system: one first-come first-served queue and three round-robin queues with quantum = 8, 16, and 32 milliseconds respectively. What is the quantum of the first-come first-served queue?

none of the others

Among CPU scheduling policies, First Come First Serve (FCFS) is attractive because

it is simple to implement

Among CPU scheduling policies, Shortest Remaining Time First (SRTF) is attractive because

it minimizes the average waiting time in the system

The _________is the essential component ofthe operating system that remains in RAM when your computer is powered on.

kernel

The is the essential component ofthe operating system that remains in RAM when your computer is powered on.

kernel

LRU replaces the page that has spent the

longest time in memory without being referenced

________ restricts access to a shared variable to only one thread at any given time

mutual exclusion

Assume that you have a page-reference string for a process with m frames (initially all empty). The page-reference string has length p; n distinct page numbers occur in it. Answer these questions for any page-replacement algorithms. What is a lower bound on the number of page faults and what is an upper bound on the number of page faults?

n, p

A server has 5 printers attached to it, and n currently running processes. Each process may require access to m printers. For which of the following values of m and n is the system susceptible to deadlocks?

n=4, m=3

A rendezvous requires

no buffering

Operating system abstraction supports the ability to have operation even when there is only one CPU available

pseudoparallelism

A ______________ is a situation in which more than one processes or threads access a shared resource concurrently, and the result depends on the order of execution

race condition

________: Causes the outcome to depend on the order in which concurrent accesses take place and is often associated with non-deterministic behavior.

race condition

All of the following are common measures of performance except

reliability

Which of the following process state transitions are legal?

running -> ready

To specify an address in this segmented memory, the fom is used

segment-number, offset

In a virtural memory environment

segmentation and page tables are stored in the RAM

Paging _________

solves the memory fragmentation problem

A page fault means that we referenced a page

that was not in main memory

In a multi-process system, at any moment every process is in one of three states: running, ready, or blocked. The transition of unblocking takes the process from blocked to running. It occurs when ________

the event for which the process is waiting completes: either the input completes, or the semaphore is released

Which of the following is true about the block size in disk space management

the larger the block size is the worse the disk space utilization is

In a multi-process system, at any moment every process is in one of three states: running, ready, or blocked. The transition of blocking takes the process from running to blocked. It occurs when ___________

the process needs to wait for input or for a semaphore or other synchonization condition

In the blocked state

the processes waiting for I/O are found

In a multi-process system, at any moment every process is in one of three states: running, ready, or blocked. The transition of being selected takes the process from ready to running. It occurs when ________

the scheduler decides to run the process

When there is an excessive amount of page swapping between main memory and secondary storage, the operation becomes inefficient, which is called .

thrashing

A ____ is a portion of a process that can run independently.

thread

_________: Allows users to interact with their programs by switching among them fast enough that the response time is usually tolerable.

OSG

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