04 - Virtual Memory

 1. What is virtual memory?

  Long-term memory

  Process for encoding information

  Large secondary memory

  A memory management technique that creates the illusion of a very large (main) memory

 2. Where is data stored when it is in virtual memory?

  A secondary storage device e.g. hard disk drive


  An optical drive e.g. CD


 3. When several programs run at the same time, the RAM can be full. Instead of closing programs, the operating system uses virtual memory to store some data.



 4. Read/Write speed of a hard disk drive is faster than RAM.



 5. Fill in the blanks.
Because of virtual memory, the memory can be shared 



  none of the mentioned


 6. Hard drive failure rates are measured with MTBF (Mean Time Between Failures). Which of these failures would be reason to replace your current hard disk?

  Application removal

  File delete

  Head crash

  Can't read CDs

 7. Fill in the blanks.
A virtual memory block is known as page, and a virtual-memory miss is 
called a________________.

  hit miss

  page fault

  page miss

  memory fault

 8. Effective access time is directly proportional to:

  memory access time

  page-fault rate

  none of these mentioned

  hit ratio

 9. Virtual memory frees applications from managing shared memory and saves users from adding more memory modules when RAM space runs out.



 10. Fill in the blanks.
The address location in the main memory, is referred to 

  static address

  logical address

  block associative

  physical address

 11. A process is thrashing if:

  it is spending more time paging than executing

  it is spending less time paging than executing

   page fault occurs

   swapping cannot take place

 12. Fill in the blanks.
Virtual memory is normally implemented by ______________.

  all of the mentioned


  demand paging


 13. The use of virtual memory slows a computer because data must be mapped between virtual and physical memory, which requires extra hardware support for address translations.



 14. The first hard disks, created in the 1950s, could be up to 20 inches in diameter. Which company invented the hard disk?





 15. When purchasing a hard disk which of these is generally NOT a specification that would be of concern?

  data rate


  mounting holes

  seek time