Operating System Solved MCQs - Part 2

A scheduling algorithm assigns priority proportional to the waiting time of a process. Every process starts with priority zero(the lowest priority). The scheduler re-evaluates the process priorities every T time units and decides the next process to schedule. Which one of the following is TRUE if the processes have no I/O operations and all arrive at time zero? This algorithm is equivalent to the first-come-first-serve algorithm This algorithm is equivalent to the round-robin algorithm This algorithm is equivalent to the shortest-job-first algorithm This algorithm is equivalent to the shortest-remaining-time-first algorithm       _____________________________________________________________________________________

A process executes the code fork(); fork(); fork(); 3 4 7 8       _____________________________________________________________________________________

Memory utilization factor shall be computed as follows  Memory in use/allocated memory Memory in use/total memory connected Memory allocated/total memory available Memory committed/total memory available       _____________________________________________________________________________________

Assume N segments in memory and a page size of P bytes. The wastage on account of internal fragmentation is NP/2 bytes P/2 bytes N/2 bytes NP bytes       _____________________________________________________________________________________

Consider a logical address space of 8 pages of 1024 words mapped with memory of 32 frames. How many bits are there in the physical address ? 9 bits 11 bits 14 bits 15 bits       _____________________________________________________________________________________

Moving process from main memory to disk is called  Scheduling Catching Swapping Spooling       _____________________________________________________________________________________

Which of the following is the process by which a user’s access to physical data in the application is limited, based on his privileges ? Authorization Authentication Access Control All of these       _____________________________________________________________________________________

Which of the following statements is not correct with reference to distributed systems ? Distributed system represents a global view of the network and considers it as a virtual uniprocessor system by controlling and managing resources across the network on all the sites. Distributed system is built on bare machine, not an add-on to the existing software. In a distributed system, kernel provides smallest possible set of services on which other services are built. This kernel is called microkernel. Open servers provide other services and access to shared resources. In a distributed system, if a user wants to run the program on other nodes or share the resources on remote sites due to their beneficial aspects, user has to log on to that site.       _____________________________________________________________________________________

In the blocked state  The processes waiting for I/O are found The process which is running is found The processes waiting for the processor are found None of the above       _____________________________________________________________________________________

Match the following : (a) Disk scheduling      1. Round-robin (b) Batch processing     2. SCAN (c) Time sharing              3. LIFO (d) Interrupt processing 4. FIFO 3   4   2   1 4   3   2   1 2   4   1   3 1   4   3   2       _____________________________________________________________________________________

In which of the following page replacement policies Balady’s anomaly occurs?  FIFO LRU LFU NRU       _____________________________________________________________________________________

The simplest way to break a deadlock is to  Preempt a resource Rollback Kill one of the processes Lock one of the processes       _____________________________________________________________________________________

Three concurrent processes X, Y, and Z execute three different code segments that access and update certain shared variables. Process X executes the P operation (i.e., wait) on semaphores a, b and c; process Y executes the P operation on semaphores b, c and d; process Z executes the P operation on semaphores c, d, and a before entering the respective code segments. After completing the execution of its code segment, each process invokes the V operation (i.e., signal) on its three semaphores. All semaphores are binary semaphores initialized to one. Which one of the following represents a deadlock- free order of invoking the P operations by the processes? X : P (a ) P (b) P (c ) Y : P (b ) P (c) P (d) Z : P (c ) P (d) P (a) X : P (b ) P (a) P (c ) Y : P (b ) P (c) P (d)  Z : P (a ) P (c ) P (d) X : P (b ) P (a) P (c ) Y : P (c ) P (b) P (d) Z : P (a ) P (c ) P (d) X : P (a ) P (b) P (c ) Y : P (c ) P (b) P (d) Z : P (c ) P (d) P (a)       _____________________________________________________________________________________

A relationship between processes such that each has some part (critical section) which must not be executed while the critical section of another is being executed, is known as Semaphore Mutual exclusion Multiprogramming Message passing       _____________________________________________________________________________________

Which of the following topologies consists of multiple CPUs connected by a single communication line running the length of the network?  Tree Ring Star Bus       _____________________________________________________________________________________

An operating system  Is not required on large computers Is always supplied with the computer Is always supplied with the BASIC Consists of programs that help in the operation of computer       _____________________________________________________________________________________

The operating system of a computer serves as a software interface between the user and Software Hardware Processor Compiler       _____________________________________________________________________________________

In one time password The password is different in each instance The password is same in each instance Both A and B None of these       _____________________________________________________________________________________

Interval between the time of submission and completion of job is called  Waiting time Turn around time Throughput Response time       _____________________________________________________________________________________

In the process management Round-robin method is essentially the pre-emptive version of _________ FILO FIFO SSF Longest time first       _____________________________________________________________________________________

System supports two types of file which are Text files Executable binary files Both a and b None of these       _____________________________________________________________________________________

There is no change. Average cohesion goes up but coupling is reduced. Average cohesion goes down and coupling also reduces. Average cohesion and coupling increase.       _____________________________________________________________________________________

In virtual memory systems, Dynamic address translation  Is the hardware necessary to implement paging Stores pages at a specific location on disk Is useless when swapping is used Is part of the operating system paging algorithm       _____________________________________________________________________________________

Which of the following is not supported by the operating system?  Protection Accounting Compilation I/O operation       _____________________________________________________________________________________

Memory on your computer where data is stored temporarily is called __________.  RAM ROM BIOS CPU       _____________________________________________________________________________________

A process executes the code fork (); fork (); fork (); fork (); The total number of child processes created is 7 9 31 15       _____________________________________________________________________________________

The multiuser operating system, 20 requests are made to use a particular resource per hour, on an average the probability that no request are made in 45 minutes is e-15 e-5 1 – e-5 1 – e-10       _____________________________________________________________________________________

Dijkstra banker algorithm is an operating system to solve the problem of dead look avoidance dead look recovery mutual exclusion contest sustaining       _____________________________________________________________________________________

Pre-emptive scheduling is the strategy of temporarily suspending a gunning process before the CPU time slice expires to allow starving processes to run when it requests I/O to avoid collision       _____________________________________________________________________________________

Consider a hard disk with 16 recording surfaces (0 -15) having 16384 cylinders (0 -16383) and each cylinder contains 64 sectors (0 - 63) . Data storage capacity in each sector is 512 bytes. Data are organized cylinder–wise and the addressing format is <cylinder no., sector no.>. A file of size 42797 KB is stored in the disk and the starting disk location of the file is <1200, 9, 40>. What is the cylinder number of the last sector of the file, if it is stored in a contiguous manner? 1281 1282 1283 1284       _____________________________________________________________________________________

The hit ratio of a Translation Look Aside Buffer (TLAB) is 80%. It takes 20 nanoseconds (ns) to search TLAB and 100 ns to access main memory. The effective memory access time is 36 ns 140 ns 122 ns 40 ns       _____________________________________________________________________________________

A thread  Is a lightweight process where the context switching is low Is a lightweight process where the context switching is high Is used to speed up paging None of the above       _____________________________________________________________________________________

File attributes are Name Type Location All of these       _____________________________________________________________________________________

Which is built directly on the hardware?  Computer Environment Application Software Operating System Database System       _____________________________________________________________________________________

A solution to the critical section problem must satisfy which requirements?  Bounded waiting, monitor and relative speed Semaphores, monitor and prevention of deadlock Signal, wait and continue Mutual exclusion, progress and bounded waiting       _____________________________________________________________________________________

______ is used in operating system to separate mechanism from policy  Single level implementation Two level implementation Multi level implementation None       _____________________________________________________________________________________

Worm was made up One program Two program Three program All of these       _____________________________________________________________________________________

Given memory partitions of 100K, 500K, 200K, 300K and 600K (in order) and processes of 212K, 417K, 112K, and 426K (in order), using the first-fit algorithm in which partition would the process requiring 426K be placed?  100K 500K 200K 600K       _____________________________________________________________________________________

The primary purpose of an operating system is  To make the most efficient use of the computer hardware To allow people to use the computer To keep systems programmers employed To make computers easier to use       _____________________________________________________________________________________

Let the page fault service time be 10  millisecond(ms) in a computer with average memory access time being 20 nanosecond(ns). If one page fault is generated for every 106 memory accesses, what is the effective access time for memory ? 21 ns 23 ns 30 ns 35 ns       _____________________________________________________________________________________

A tree structured file directory system  Allows easy storage and retrieval of file names Is a much debated unnecessary feature Is not essential when we have millions of files None of the above       _____________________________________________________________________________________

Security violation due to  Malicious Accidental Both A and B None of these       _____________________________________________________________________________________

Multiprogramming systems  Are easier to develop than single programming systems Execute each job faster Execute more jobs in the same time period Are used only one large mainframe computers       _____________________________________________________________________________________

The most common approach to authenticating a user identity is  User password User log in Hardware device None of these       _____________________________________________________________________________________

A starvation-free job-scheduling policy guarantees that no job waits indefinitely for service. Which of the following job-scheduling policies is starvation-free? Round-robin Priority queuing Shortest job first Youngest job first       _____________________________________________________________________________________

Which of the following statement is wrong ? I. 2-phase locking protocol suffer from dead lock. II. Time stamp protocol suffer from more aborts. III. A block hole in a DFD is a data store with only inbound flows. IV. Multivalued dependency among attribute is checked at 3 NF level. V. An entity-relationship diagram is a tool to represent event model. I, II, II II, III, IV III, IV, V II, IV, V       _____________________________________________________________________________________

Remote Computing Service involves the use of time sharing and _______. multi-processing interactive processing batch processing real-time processing       _____________________________________________________________________________________

Cascading termination refers to termination of all child processes before the parent terminates  Normally Abnormally Normally or abnormally None of these       _____________________________________________________________________________________

In round robin CPU scheduling as time quantum is increased the average turn around time increases decreases remains constant varies irregularly       _____________________________________________________________________________________

At intermediate multiprogramming levels, the rate of increase of throughput with multiprogramming levels decreases. This phenomenon is best explained by the fact that as multiprogramming level increases I/O activities per request remains constant Some system resources begins to saturate (i.e., to be utilized 100%) The utilization of memory improves The average time spent in the system by each request increases       _____________________________________________________________________________________