Operating System (OS) QUESTIONS AND ANSWERS

Which of the following can be said about a segmentation fault caused when a process is active? It will recover from the fault transparently to the user, by moving the required page from the secondary memory The fault’s cause may most likely be an error in programming It will not abruptly terminate the process and a core image of the process will be saved for further observations It will cause the process to go into the ‘blocked’ state It will most likely be caused by a hardware fault. A common programming construct for implementing mutual exclusion which uses condition variables is called Suppose requests have recently arrived for data on cylinders 25, 46, 12, and 3, in that order, and that the read-write head is currently at cylinder 20. If the disk scheduling policy is SSTF, the outstanding requests will be serviced in the order (a) Semaphore (b) Deadlock (c) Monitor (d) Locking interrupts (e) Threads. (a) 25, 46, 12, 3 (b) 25, 46, 3, 12 (c) 3, 12, 25, 46 (d) 25, 12, 3, 46 (e) 12,3,25,46. DMA stands for Direct Management access (c) Dual memory access (e) Dual memory array. (b) Direct memory access (d) Data memory access

Which of the following disk-scheduling methods is most likely to lead to starvation for requests on inner or outer cylinders? FCFS (b) SSTF (c) SCAN (d) C-SCAN (e) b-SCAN. Which of the following is in correct order of size, smallest first? (a) Cylinder, track, sector (b) Cylinder, sector, track (c) (e) Sector, track, cylinder Track, cylinder, sector. (d) Sector, cylinder, track process that executes a READ instruction for a data record currently on disk will undergo a process state transition from Ready to blocked (b)Running to blocked (c) Blocked to ready (d) Blocked to running (e) Terminated. In a certain system, process A has just arrived at time 0, process B at time 3, and process C at time 6. A needs 5 seconds in the CPU, B 3 seconds, and C 1 second. All processes are totally CPU-bound and process-switching time is negligible, so that after 9 seconds all processes have completed. At what time does process B complete if the process-scheduling algorithm is preemptive SJF and the quantum is 1 second? (a) 6 (b) 7 (c) 8 (d) 9 (e) 10. If the value of a binary semaphore S is 0, and a process executes a WAIT instruction on S, then S will remain zero and the process will proceed S will remain zero and the process will be placed on a queue S will become one and the process will proceed S will become one and the process will be placed on a queue S will become -1 and the process will not be placed on a queue.

The process of collecting fragments of available memory space into contiguous blocks by moving programs and data in a computer's memory or disk is known as Compaction (b) Coalescing (c) Segmentation (d) Fragmentation (e) Paging. Which of the following controls all the computer resources and provides the base upon which the application programs can be written? Which of the following system call loads a process into memory? Load (b) Create (c) Fork (d) Execv (e) Copy. Expand the term UNICS Uniplexed Information Computing System Unipoint Information Computing System Uniplexed Instruction Computing System Unipoint Instruction Computing System Union Instruction Common System. Which of the following software layer is used between the kernel and the user computations in the network O.S? Which of the following allows many users to share the computer simultaneously? (a) Application Software (b) C.P.U (c) Operating System (d) Bare Hardware (e) Device Drivers. (a) Local O.S (b) Network O.S (c) Global O.S (d) Distributed O.S (e) Remote O.S. (a) Time Sharing O.S (b) Real Time O.S (c) Interactive O.S (d) Batch O.S (e) Network O.S.

If a program is under execution by CPU then we say the process is under Each process is represented in the operating system by its own Thread (b) PCB (c) State (d) Instructions (e) PCC. The amount of time that a job waits in a ready queue for getting selected by CPU is called Turnaround time (b) Waiting time (c) Completion time (d) Submission time (e) Throughput. The process of storing and restoring from PCB is called Which of the following memory management scheme loads all pages of a program from disk into main memory? (a) CPU Burst (b) Process (c) I/O Burst (d) Ready Queue (e) New State. (a) Loading (b) Relocation (c) Dispatcher (d) Process (e) context switch. (a) Paging (b) Demand paging (c) (e) Segmentation Demand segmentation. (d) Segmentation with paging Which of the following page replacement algorithm use the technique of replace that page which is not used in the near future? LRU (b) LFU (c) ORA (d) FIFO (e) MFU. The set of pages that a process is currently using is called as (a) Program (b) Page Group (c) Working Group (d) Working Set (e) None of the above.

Which of the following registers contains starting address of the program in the main memory? The process of converting logical address into physical address is known as (a) Address register (b) Base register (c) GPR (d) Index register (e) Limit register. (a) Conversion (b) Displacement (d) Transfer (c) Relocation (e) None of the above. In a segmentation scheme the logical memory will be divided into Pages (b) Frames (c) Blocks (d) Cells (e) Segments. Which of the following area is used to store the O.S programs in the main memory? In Unix which of the following system calls returns the meta data about a file? fstat (b) mstat (c) Metacall (d) Sigabort (e) fork. Information in the file is processed in order, one record after another. This mode of access is called . Relative (b) Sequential (c) Direct (d) Index (e) Indexed- sequential. Which of the technique is used to recover the process from starvation situation? Paging (b) Aging (c) Compaction (d) Starvation (e) Reduction. Before we store data into a disk, it must be divided into sectors and from where the disk controller can read and write. This is known as_ _. (a) User memory area (b) Monitor memory area (c) Heap area (d) Stack area (e) Data area. (a) Low-level formatting (b) Fragmenting (c) High-level formatting (d) Cleaning (e) Portioning a disk.

51.The disk controller can be told to replace each bad sector logically with one of the spare sectors in the disk. This scheme is known as _. (a) Sector sparing (d) Back word replacing (b) Sector slipping (c) Forwarding (e) Sector replace. Controlling the access of programs, processes or users to the resources defined by the system is known as . The _________ are reserved for events such as unrecoverable memory errors. a)nonmaskable interrupts b) blocked interrupts c) maskable interrupts d) None of these Which of the following mechanism is used to achieve concurrency control? Every process before starting execution should know what resources are allocated to it. This is known as The ability to execute an operation on an object is known as The time required to move the disk head to the desired track is known as (a) Prevention (b) Security (c) Protection (d) Access stop (e) Access right. (a) Clusters (b) Triggers (c) Control access (d) Cursors (e) Locks. (a) Know-to-need (b) Need-to-Know (c) Know about what (d) Need-to-use (e) Know-to-use. (a) Access Right (b) Access Control (c) Domain Knowledge (d) Control Right (e) Protection. (a) Access Time (b) Track Time (c) Latency Time (d) Seek Time (e) Block Time.

58. distributed system is a collection of processors that do not share . CPU (b) Memory (c) I/O devices (d) Network (e) File. The name of the file does not reveal any hint of the file’s physical storage location is called_ _. Location independence (b) Protection (c) Location transparency (d) File migration (e) Inter-machine interface. Software entity running on one or more machines and providing a particular type of function to a priori unknown clients is called . Client (b) Server (c) Service (d) Process (e) None of the above.

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