3i Infotech Placement: Sample Questions 296 - 297 of 1245

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Question 296

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Describe in Detail

Essay▾

Define disk swapping and file system swapping?

Explanation

Swap File in Figure

Disk swapping vs. file system swapping

Disk swapping:

  • The practice of inserting and removing, or swapping, floppy disks in a floppy disk drive-based computer system.
  • Allows running the program not loaded into memory- first remove the data disk, then insert the program disk.
  • Disk swapping inconvenient feature of early Macintosh 128K systems to save RAM.

File system swapping:

  • A space on a hard disk used as the virtual memory extension of a computer՚s real memory.
  • A swap file allows computer՚s operating system to allocate more RAM than actually present in computer.
  • Operating system move memory from swap file to RAM in units called pages and the process is called paging.

Question 297

Question

MCQ▾

EMPNO ENAME SAL

A822 RAMASWAMY 3500

A812 NARAYAN 5000

A973 UMESH

A500 BALAJI 5750

Using the above data

Select count (sal) from Emp will retrieve

Choices

Choice (4)

a.

3

b.

0

c.

1

d.

None of the above

Answer

a.

Explanation

These are only three salaries in the database and hence it will count the number of salaries. NULL is ignored like in most of the combination statements.

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