OSG
____ 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
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 (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?
Close
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
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
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?
1
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.
10
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.
10
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
11
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
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 FCFS
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
15
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
2
How many ways is Thread implemented?
2
There are ___________entries per page in the Page table.
2
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
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-LOOK disc scheduling algorithm
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
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 RR scheduling with a time quantum of 4 msec
39.4 msec
Which is the maximum number of partition that most disks can be divided up?
4
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
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 FCFS disc scheduling algorithm.
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.
7
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
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 SJF
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 __________
9
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
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 Round Robin RR(quantum=1)
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?
RR
Which scheduling algorithm is better for an interactive system?
RR
Which scheduling policy is most suitable for a time shared operating systems?
RR
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.
time-shared systems
In a fixed magnetic disk, each circle is called a
track
Which of the following is not related to disk scheduling
transfer time