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This set of Operating System (OS) Multiple Choice Questions & Answers (MCQs) focuses on Operating System Set 19

Q1 | The minimum number of page frames that must be allocated to a running process in a virtual memory environment is determined by
  • the instruction set architecture
  • page size
  • physical memory size
  • number of processes in memory
Q2 | What is the reason for using the LFU page replacement algorithm?
  • an actively used page should have a large reference count
  • a less used page has more chances to be used again
  • it is extremely efficient and optimal
  • all of the mentioned
Q3 | In segmentation, each address is specified by                          
  • a segment number & offset
  • an offset & value
  • a value & segment number
  • a key & value
Q4 | Each entry in a segment table has a
  • segment base
  • segment peak
  • segment value
  • none of the mentioned
Q5 | The segment limit contains the
  • starting logical address of the process
  • starting physical address of the segment in memory
  • segment length
  • none of the mentioned
Q6 | The offset ‘d’ of the logical address must be                          
  • greater than segment limit
  • between 0 and segment limit
  • between 0 and the segment number
  • greater than the segment number
Q7 | If the offset is legal                          
  • it is used as a physical memory address itself
  • it is subtracted from the segment base to produce the physical memory address
  • it is added to the segment base to produce the physical memory address
  • none of the mentioned
Q8 | When the entries in the segment tables of two different processes point to the same physical location                          
  • the segments are invalid
  • the processes get blocked
  • segments are shared
  • all of the mentioned
Q9 | The protection bit is 0/1 based on
  • write only
  • read only
  • read – write
  • none of the mentioned
Q10 | If there are 32 segments, each of size 1Kb, then the logical address should have
  • 13 bits
  • 14 bits
  • 15 bits
  • 16 bits
Q11 | Consider a computer with 8 Mbytes of main memory and a 128K cache. The cache block size is 4 K. It uses a direct mapping scheme for cache management. How many different main memory blocks can map onto a given physical cache block?
  • 2048
  • 256
  • 64
  • 8
Q12 | A multilevel page table is preferred in comparison to a single level page table for translating virtual address to physical address because                          
  • it reduces the memory access time to read or write a memory location
  • it helps to reduce the size of page table needed to implement the virtual address space of a process
  • it is required by the translation lookaside buffer
  • it helps to reduce the number of page faults in page replacement algorithms
Q13 | In                information is recorded magnetically on platters.
  • magnetic disks
  • electrical disks
  • assemblies
  • cylinders
Q14 | The heads of the magnetic disk are attached to a            that moves all the heads as a unit.
  • spindle
  • disk arm
  • track
  • none of the mentioned
Q15 | The set of tracks that are at one arm position make up a                        
  • magnetic disks
  • electrical disks
  • assemblies
  • cylinders
Q16 | The time taken to move the disk arm to the desired cylinder is called the                          
  • positioning time
  • random access time
  • seek time
  • rotational latency
Q17 | The time taken for the desired sector to rotate to the disk head is called
  • positioning time
  • random access time
  • seek time
  • rotational latency
Q18 | When the head damages the magnetic surface, it is known as                    
  • disk crash
  • head crash
  • magnetic damage
  • all of the mentioned
Q19 | What is the host controller?
  • controller built at the end of each disk
  • controller at the computer end of the bus
  • all of the mentioned
  • none of the mentioned
Q20 |              controller sends the command placed into it, via messages to the             controller.
  • host, host
  • disk, disk
  • host, disk
  • disk, host
Q21 | What is the disk bandwidth?
  • the total number of bytes transferred
  • total time between the first request for service and the completion on the last transfer
  • the total number of bytes transferred divided by the total time between the first request for service and the completion on the last transfer
  • none of the mentioned
Q22 | Whenever a process needs I/O to or from a disk it issues a                              
  • system call to the cpu
  • system call to the operating system
  • a special procedure
  • all of the mentioned
Q23 | If a process needs I/O to or from a disk, and if the drive or controller is busy then
  • the request will be placed in the queue of pending requests for that drive
  • the request will not be processed and will be ignored completely
  • the request will be not be placed
  • none of the mentioned
Q24 | Magnetic tape drives can write data at a speed                  disk drives.
  • much lesser than
  • comparable to
  • much faster than
  • none of the mentioned
Q25 | On media that use constant linear velocity (CLV), the                            is uniform.
  • density of bits on the disk
  • density of bits per sector
  • the density of bits per track
  • none of the mentioned