McqMate
| 401. |
The is used as an index into the page table. |
| A. | frame bit |
| B. | page number |
| C. | page offset |
| D. | frame offset |
| Answer» B. page number | |
| 402. |
The table contains the base address of each page in physical memory. |
| A. | process |
| B. | memory |
| C. | page |
| D. | frame |
| Answer» C. page | |
| 403. |
The size of a page is typically |
| A. | varied |
| B. | power of 2 |
| C. | power of 4 |
| D. | none of the mentioned |
| Answer» B. power of 2 | |
| 404. |
If the size of logical address space is 2 to the power of m, and a page size is 2 to the power of n addressing units, then the high order bits of a logical address designate the page number, and the low order bits designate the page offset. |
| A. | m, n |
| B. | n, m |
| C. | m – n, m |
| D. | m – n, n |
| Answer» D. m – n, n | |
| 405. |
The operating system maintains a table that keeps track of how many frames have been allocated, how many are there, and how many are available. |
| A. | page |
| B. | mapping |
| C. | frame |
| D. | memory |
| Answer» C. frame | |
| 406. |
Paging increases the time. |
| A. | waiting |
| B. | execution |
| C. | context – switch |
| D. | all of the mentioned |
| Answer» C. context – switch | |
| 407. |
Smaller page tables are implemented as a set of |
| A. | queues |
| B. | stacks |
| C. | counters |
| D. | registers |
| Answer» D. registers | |
| 408. |
The page table registers should be built with |
| A. | very low speed logic |
| B. | very high speed logic |
| C. | a large memory space |
| D. | none of the mentioned |
| Answer» B. very high speed logic | |
| 409. |
For larger page tables, they are kept in main memory and a points to the page table. |
| A. | page table base register |
| B. | page table base pointer |
| C. | page table register pointer |
| D. | page table base |
| Answer» A. page table base register | |
| 410. |
For every process there is a |
| A. | page table |
| B. | copy of page table |
| C. | pointer to page table |
| D. | all of the mentioned |
| Answer» A. page table | |
| 411. |
Time taken in memory access through PTBR is |
| A. | extended by a factor of 3 |
| B. | extended by a factor of 2 |
| C. | slowed by a factor of 3 |
| D. | slowed by a factor of 2 |
| Answer» D. slowed by a factor of 2 | |
| 412. |
Each entry in a translation lookaside buffer (TLB) consists of |
| A. | key |
| B. | value |
| C. | bit value |
| D. | constant |
| Answer» A. key | |
| 413. |
If a page number is not found in the TLB, then it is known as a |
| A. | tlb miss |
| B. | buffer miss |
| C. | tlb hit |
| D. | all of the mentioned |
| Answer» A. tlb miss | |
| 414. |
An uniquely identifies processes and is used to provide address space protection for that process. |
| A. | address space locator |
| B. | address space identifier |
| C. | address process identifier |
| D. | none of the mentioned |
| Answer» B. address space identifier | |
| 415. |
The percentage of times a page number is found in the TLB is known as |
| A. | miss ratio |
| B. | hit ratio |
| C. | miss percent |
| D. | none of the mentioned |
| Answer» B. hit ratio | |
| 416. |
Memory protection in a paged environment is accomplished by |
| A. | protection algorithm with each page |
| B. | restricted access rights to users |
| C. | restriction on page visibility |
| D. | protection bit with each page |
| Answer» D. protection bit with each page | |
| 417. |
When the valid – invalid bit is set to valid, it means that the associated page |
| A. | is in the tlb |
| B. | has data in it |
| C. | is in the process’s logical address space |
| D. | is the system’s physical address space |
| Answer» C. is in the process’s logical address space | |
| 418. |
When there is a large logical address space, the best way of paging would be |
| A. | not to page |
| B. | a two level paging algorithm |
| C. | the page table itself |
| D. | all of the mentioned |
| Answer» B. a two level paging algorithm | |
| 419. |
is the concept in which a process is copied into the main memory from the secondary memory according to the requirement. |
| A. | paging |
| B. | demand paging |
| C. | segmentation |
| D. | swapping |
| Answer» B. demand paging | |
| 420. |
The pager concerns with the |
| A. | special support from hardware is required |
| B. | special support from operating system is essential |
| C. | special support from both hardware and operating system is essential |
| D. | user programs can implement dynamic loading without any special support from hardware or operating system |
| Answer» D. user programs can implement dynamic loading without any special support from hardware or operating system | |
| 421. |
In paged memory systems, if the page size is increased, then the internal fragmentation generally |
| A. | becomes less |
| B. | becomes more |
| C. | remains constant |
| D. | none of the mentioned |
| Answer» B. becomes more | |
| 422. |
Swap space exists in |
| A. | primary memory |
| B. | secondary memory |
| C. | cpu |
| D. | none of the mentioned |
| Answer» B. secondary memory | |
| 423. |
When a program tries to access a page that is mapped in address space but not loaded in physical memory, then |
| A. | segmentation fault occurs |
| B. | fatal error occurs |
| C. | page fault occurs |
| D. | no error occurs |
| Answer» C. page fault occurs | |
| 424. |
Effective access time is directly proportional to |
| A. | page-fault rate |
| B. | hit ratio |
| C. | memory access time |
| D. | none of the mentioned |
| Answer» A. page-fault rate | |
| 425. |
In FIFO page replacement algorithm, when a page must be replaced |
| A. | oldest page is chosen |
| B. | newest page is chosen |
| C. | random page is chosen |
| D. | none of the mentioned |
| Answer» A. oldest page is chosen | |
| 426. |
Virtual memory allows |
| A. | execution of a process that may not be completely in memory |
| B. | a program to be smaller than the physical memory |
| C. | a program to be larger than the secondary storage |
| D. | execution of a process without being in physical memory |
| Answer» A. execution of a process that may not be completely in memory | |
| 427. |
A process is thrashing if |
| A. | it is spending more time paging than executing |
| B. | it is spending less time paging than executing |
| C. | page fault occurs |
| D. | swapping can not take place |
| Answer» A. it is spending more time paging than executing | |
| 428. |
The ability to execute a program that is only partially in memory has benefits like |
| A. | the amount of physical memory cannot put a constraint on the program |
| B. | programs for an extremely large virtual space can be created |
| C. | throughput increases |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 429. |
Virtual memory is normally implemented by |
| A. | demand paging |
| B. | buses |
| C. | virtualization |
| D. | all of the mentioned |
| Answer» A. demand paging | |
| 430. |
Segment replacement algorithms are more complex than page replacement algorithms because |
| A. | segments are better than pages |
| B. | pages are better than segments |
| C. | segments have variable sizes |
| D. | segments have fixed sizes |
| Answer» C. segments have variable sizes | |
| 431. |
A swapper manipulates whereas the pager is concerned with individual of a process. |
| A. | the entire process, parts |
| B. | all the pages of a process, segments |
| C. | the entire process, pages |
| D. | none of the mentioned |
| Answer» C. the entire process, pages | |
| 432. |
Using a pager |
| A. | increases the swap time |
| B. | decreases the swap time |
| C. | decreases the swap time & amount of physical memory needed |
| D. | increases the amount of physical memory needed |
| Answer» C. decreases the swap time & amount of physical memory needed | |
| 433. |
The valid – invalid bit, in this case, when valid indicates? |
| A. | the page is not legal |
| B. | the page is illegal |
| C. | the page is in memory |
| D. | the page is not in memory |
| Answer» C. the page is in memory | |
| 434. |
A page fault occurs when? |
| A. | a page gives inconsistent data |
| B. | a page cannot be accessed due to its absence from memory |
| C. | a page is invisible |
| D. | all of the mentioned |
| Answer» B. a page cannot be accessed due to its absence from memory | |
| 435. |
When a page fault occurs, the state of the interrupted process is |
| A. | disrupted |
| B. | invalid |
| C. | saved |
| D. | none of the mentioned |
| Answer» C. saved | |
| 436. |
When a process begins execution with no pages in memory? |
| A. | process execution becomes impossible |
| B. | a page fault occurs for every page brought into memory |
| C. | process causes system crash |
| D. | none of the mentioned |
| Answer» B. a page fault occurs for every page brought into memory | |
| 437. |
If the memory access time is denoted by ‘ma’ and ‘p’ is the probability of a page fault (0 <= p <= 1). Then the effective access time for a demand paged memory is |
| A. | p x ma + (1-p) x page fault time |
| B. | ma + page fault time |
| C. | (1-p) x ma + p x page fault time |
| D. | none of the mentioned |
| Answer» C. (1-p) x ma + p x page fault time | |
| 438. |
When the page fault rate is low |
| A. | the turnaround time increases |
| B. | the effective access time increases |
| C. | the effective access time decreases |
| D. | turnaround time & effective access time increases |
| Answer» C. the effective access time decreases | |
| 439. |
Locality of reference implies that the page reference being made by a process |
| A. | will always be to the page used in the previous page reference |
| B. | is likely to be one of the pages used in the last few page references |
| C. | will always be one of the pages existing in memory |
| D. | will always lead to page faults |
| Answer» B. is likely to be one of the pages used in the last few page references | |
| 440. |
Which of the following page replacement algorithms suffers from Belady’s Anomaly? |
| A. | optimal replacement |
| B. | lru |
| C. | fifo |
| D. | both optimal replacement and fifo |
| Answer» C. fifo | |
| 441. |
In question 2, if the number of page frames is increased to 4, then the number of page transfers |
| A. | decreases |
| B. | increases |
| C. | remains the same |
| D. | none of the mentioned |
| Answer» B. increases | |
| 442. |
A memory page containing a heavily used variable that was initialized very early and is in constant use is removed, then the page replacement algorithm used is |
| A. | lru |
| B. | lfu |
| C. | fifo |
| D. | none of the mentioned |
| Answer» C. fifo | |
| 443. |
Users that their processes are running on a paged system. |
| A. | are aware |
| B. | are unaware |
| C. | may unaware |
| D. | none of the mentioned |
| Answer» B. are unaware | |
| 444. |
If no frames are free, page transfer(s) is/are required. |
| A. | one |
| B. | two |
| C. | three |
| D. | four |
| Answer» B. two | |
| 445. |
A FIFO replacement algorithm associates with each page the |
| A. | time it was brought into memory |
| B. | size of the page in memory |
| C. | page after and before it |
| D. | all of the mentioned |
| Answer» A. time it was brought into memory | |
| 446. |
What is the Optimal page – replacement algorithm? |
| A. | replace the page that has not been used for a long time |
| B. | replace the page that has been used for a long time |
| C. | replace the page that will not be used for a long time |
| D. | none of the mentioned |
| Answer» C. replace the page that will not be used for a long time | |
| 447. |
LRU page – replacement algorithm associates with each page the |
| A. | time it was brought into memory |
| B. | the time of that page’s last use |
| C. | page after and before it |
| D. | all of the mentioned |
| Answer» B. the time of that page’s last use | |
| 448. |
What are the two methods of the LRU page replacement policy that can be implemented in hardware? |
| A. | counters |
| B. | ram & registers |
| C. | stack & counters |
| D. | registers |
| Answer» C. stack & counters | |
| 449. |
When using counters to implement LRU, we replace the page with the |
| A. | smallest time value |
| B. | largest time value |
| C. | greatest size |
| D. | none of the mentioned |
| Answer» A. smallest time value | |
| 450. |
There is a set of page replacement algorithms that can never exhibit Belady’s Anomaly, called |
| A. | queue algorithms |
| B. | stack algorithms |
| C. | string algorithms |
| D. | none of the mentioned |
| Answer» B. stack algorithms | |
| 451. |
The minimum number of page frames that must be allocated to a running process in a virtual memory environment is determined by |
| A. | the instruction set architecture |
| B. | page size |
| C. | physical memory size |
| D. | number of processes in memory |
| Answer» A. the instruction set architecture | |
| 452. |
What is the reason for using the LFU page replacement algorithm? |
| A. | an actively used page should have a large reference count |
| B. | a less used page has more chances to be used again |
| C. | it is extremely efficient and optimal |
| D. | all of the mentioned |
| Answer» A. an actively used page should have a large reference count | |
| 453. |
In segmentation, each address is specified by |
| A. | a segment number & offset |
| B. | an offset & value |
| C. | a value & segment number |
| D. | a key & value |
| Answer» A. a segment number & offset | |
| 454. |
Each entry in a segment table has a |
| A. | segment base |
| B. | segment peak |
| C. | segment value |
| D. | none of the mentioned |
| Answer» A. segment base | |
| 455. |
The segment limit contains the |
| A. | starting logical address of the process |
| B. | starting physical address of the segment in memory |
| C. | segment length |
| D. | none of the mentioned |
| Answer» C. segment length | |
| 456. |
The offset ‘d’ of the logical address must be |
| A. | greater than segment limit |
| B. | between 0 and segment limit |
| C. | between 0 and the segment number |
| D. | greater than the segment number |
| Answer» B. between 0 and segment limit | |
| 457. |
If the offset is legal |
| A. | it is used as a physical memory address itself |
| B. | it is subtracted from the segment base to produce the physical memory address |
| C. | it is added to the segment base to produce the physical memory address |
| D. | none of the mentioned |
| Answer» A. it is used as a physical memory address itself | |
| 458. |
When the entries in the segment tables of two different processes point to the same physical location |
| A. | the segments are invalid |
| B. | the processes get blocked |
| C. | segments are shared |
| D. | all of the mentioned |
| Answer» C. segments are shared | |
| 459. |
The protection bit is 0/1 based on |
| A. | write only |
| B. | read only |
| C. | read – write |
| D. | none of the mentioned |
| Answer» C. read – write | |
| 460. |
If there are 32 segments, each of size 1Kb, then the logical address should have |
| A. | 13 bits |
| B. | 14 bits |
| C. | 15 bits |
| D. | 16 bits |
| Answer» C. 15 bits | |
| 461. |
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? |
| A. | 2048 |
| B. | 256 |
| C. | 64 |
| D. | 8 |
| Answer» C. 64 | |
| 462. |
A multilevel page table is preferred in comparison to a single level page table for translating virtual address to physical address because |
| A. | it reduces the memory access time to read or write a memory location |
| B. | it helps to reduce the size of page table needed to implement the virtual address space of a process |
| C. | it is required by the translation lookaside buffer |
| D. | it helps to reduce the number of page faults in page replacement algorithms |
| Answer» B. it helps to reduce the size of page table needed to implement the virtual address space of a process | |
| 463. |
In information is recorded magnetically on platters. |
| A. | magnetic disks |
| B. | electrical disks |
| C. | assemblies |
| D. | cylinders |
| Answer» A. magnetic disks | |
| 464. |
The heads of the magnetic disk are attached to a that moves all the heads as a unit. |
| A. | spindle |
| B. | disk arm |
| C. | track |
| D. | none of the mentioned |
| Answer» B. disk arm | |
| 465. |
The set of tracks that are at one arm position make up a |
| A. | magnetic disks |
| B. | electrical disks |
| C. | assemblies |
| D. | cylinders |
| Answer» D. cylinders | |
| 466. |
The time taken to move the disk arm to the desired cylinder is called the |
| A. | positioning time |
| B. | random access time |
| C. | seek time |
| D. | rotational latency |
| Answer» C. seek time | |
| 467. |
The time taken for the desired sector to rotate to the disk head is called |
| A. | positioning time |
| B. | random access time |
| C. | seek time |
| D. | rotational latency |
| Answer» D. rotational latency | |
| 468. |
When the head damages the magnetic surface, it is known as |
| A. | disk crash |
| B. | head crash |
| C. | magnetic damage |
| D. | all of the mentioned |
| Answer» B. head crash | |
| 469. |
What is the host controller? |
| A. | controller built at the end of each disk |
| B. | controller at the computer end of the bus |
| C. | all of the mentioned |
| D. | none of the mentioned |
| Answer» B. controller at the computer end of the bus | |
| 470. |
controller sends the command placed into it, via messages to the controller. |
| A. | host, host |
| B. | disk, disk |
| C. | host, disk |
| D. | disk, host |
| Answer» C. host, disk | |
| 471. |
What is the disk bandwidth? |
| A. | the total number of bytes transferred |
| B. | total time between the first request for service and the completion on the last transfer |
| C. | the total number of bytes transferred divided by the total time between the first request for service and the completion on the last transfer |
| D. | none of the mentioned |
| Answer» C. the total number of bytes transferred divided by the total time between the first request for service and the completion on the last transfer | |
| 472. |
Whenever a process needs I/O to or from a disk it issues a |
| A. | system call to the cpu |
| B. | system call to the operating system |
| C. | a special procedure |
| D. | all of the mentioned |
| Answer» B. system call to the operating system | |
| 473. |
If a process needs I/O to or from a disk, and if the drive or controller is busy then |
| A. | the request will be placed in the queue of pending requests for that drive |
| B. | the request will not be processed and will be ignored completely |
| C. | the request will be not be placed |
| D. | none of the mentioned |
| Answer» A. the request will be placed in the queue of pending requests for that drive | |
| 474. |
Magnetic tape drives can write data at a speed disk drives. |
| A. | much lesser than |
| B. | comparable to |
| C. | much faster than |
| D. | none of the mentioned |
| Answer» B. comparable to | |
| 475. |
On media that use constant linear velocity (CLV), the is uniform. |
| A. | density of bits on the disk |
| B. | density of bits per sector |
| C. | the density of bits per track |
| D. | none of the mentioned |
| Answer» C. the density of bits per track | |
| 476. |
SSTF algorithm, like SJF of some requests. |
| A. | may cause starvation |
| B. | will cause starvation |
| C. | does not cause starvation |
| D. | causes aging |
| Answer» A. may cause starvation | |
| 477. |
In the algorithm, the disk arm starts at one end of the disk and moves toward the other end, servicing requests till the other end of the disk. At the other end, the direction is reversed and servicing continues. |
| A. | look |
| B. | scan |
| C. | c-scan |
| D. | c-look |
| Answer» B. scan | |
| 478. |
In the algorithm, the disk head moves from one end to the other, servicing requests along the way. When the head reaches the other end, it immediately returns to the beginning of the disk without servicing any requests on the return trip. |
| A. | look |
| B. | scan |
| C. | c-scan |
| D. | c-look |
| Answer» C. c-scan | |
| 479. |
The process of dividing a disk into sectors that the disk controller can read and write, before a disk can store data is known as |
| A. | partitioning |
| B. | swap space creation |
| C. | low-level formatting |
| D. | none of the mentioned |
| Answer» C. low-level formatting | |
| 480. |
The data structure for a sector typically contains |
| A. | header |
| B. | data area |
| C. | trailer |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 481. |
The header and trailer of a sector contain information used by the disk controller such as and |
| A. | main section & disk identifier |
| B. | error correcting codes (ecc) & sector number |
| C. | sector number & main section |
| D. | disk identifier & sector number |
| Answer» B. error correcting codes (ecc) & sector number | |
| 482. |
The program initializes all aspects of the system, from CPU registers to device controllers and the contents of main memory, and then starts the operating system. |
| A. | main |
| B. | bootloader |
| C. | bootstrap |
| D. | rom |
| Answer» C. bootstrap | |
| 483. |
For most computers, the bootstrap is stored in |
| A. | RAM |
| B. | ROM |
| C. | cache |
| D. | tertiary storage |
| Answer» B. ROM | |
| 484. |
The scheme used in the above question is known as or |
| A. | sector sparing & forwarding |
| B. | forwarding & sector utilization |
| C. | backwarding & forwarding |
| D. | sector utilization & backwarding |
| Answer» A. sector sparing & forwarding | |
| 485. |
A disk that has a boot partition is called a |
| A. | start disk |
| B. | end disk |
| C. | boot disk |
| D. | all of the mentioned |
| Answer» C. boot disk | |
| 486. |
If one or more devices use a common set of wires to communicate with the computer system, the connection is called |
| A. | cpu |
| B. | monitor |
| C. | wirefull |
| D. | bus |
| Answer» D. bus | |
| 487. |
When device A has a cable that plugs into device B, and device B has a cable that plugs into device C and device C plugs into a port on the computer, this arrangement is called a |
| A. | port |
| B. | daisy chain |
| C. | bus |
| D. | cable |
| Answer» B. daisy chain | |
| 488. |
The present a uniform device- access interface to the I/O subsystem, much as system calls provide a standard interface between the application and the operating system. |
| A. | devices |
| B. | buses |
| C. | device drivers |
| D. | i/o systems |
| Answer» C. device drivers | |
| 489. |
The register is read by the host to get input. |
| A. | flow in |
| B. | flow out |
| C. | data in |
| D. | data out |
| Answer» C. data in | |
| 490. |
The register is written by the host to send output. |
| A. | status |
| B. | control |
| C. | data in |
| D. | data out |
| Answer» D. data out | |
| 491. |
The hardware mechanism that allows a device to notify the CPU is called |
| A. | polling |
| B. | interrupt |
| C. | driver |
| D. | controlling |
| Answer» B. interrupt | |
| 492. |
The determines the cause of the interrupt, performs the necessary processing and executes a return from the interrupt instruction to return the CPU to the execution state prior to the interrupt. |
| A. | interrupt request line |
| B. | device driver |
| C. | interrupt handler |
| D. | all of the mentioned |
| Answer» C. interrupt handler | |
| 493. |
In general the two interrupt request lines are |
| A. | maskable & non maskable interrupts |
| B. | blocked & non maskable interrupts |
| C. | maskable & blocked interrupts |
| D. | none of the mentioned |
| Answer» A. maskable & non maskable interrupts | |
| 494. |
The are reserved for events such as unrecoverable memory errors. |
| A. | non maskable interrupts |
| B. | blocked interrupts |
| C. | maskable interrupts |
| D. | none of the mentioned |
| Answer» A. non maskable interrupts | |
| 495. |
The can be turned off by the CPU before the execution of critical instruction sequences that must not be interrupted. |
| A. | nonmaskable interrupt |
| B. | blocked interrupt |
| C. | maskable interrupt |
| D. | none of the mentioned |
| Answer» C. maskable interrupt | |
| 496. |
The is used by device controllers to request service. |
| A. | nonmaskable interrupt |
| B. | blocked interrupt |
| C. | maskable interrupt |
| D. | none of the mentioned |
| Answer» C. maskable interrupt | |
| 497. |
The interrupt vector contains |
| A. | the interrupts |
| B. | the memory addresses of specialized interrupt handlers |
| C. | the identifiers of interrupts |
| D. | the device addresses |
| Answer» B. the memory addresses of specialized interrupt handlers | |
| 498. |
Division by zero, accessing a protected or non existent memory address, or attempting to execute a privileged instruction from user mode are all categorized as |
| A. | errors |
| B. | exceptions |
| C. | interrupt handlers |
| D. | all of the mentioned |
| Answer» B. exceptions | |
| 499. |
For large data transfers, is used. |
| A. | dma |
| B. | programmed i/o |
| C. | controller register |
| D. | none of the mentioned |
| Answer» A. dma | |
| 500. |
A character stream device transfers |
| A. | bytes one by one |
| B. | block of bytes as a unit |
| C. | with unpredictable response times |
| D. | none of the mentioned |
| Answer» A. bytes one by one | |
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