Basic CS-Operating System [3i Infotech Placement]: Sample Questions 85 - 87 of 89

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Question 85

Operating System
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Describe in Detail

Essay▾

What are the typical elements of a process image?

Explanation

Process image consists of:

User Data

  • Modifiable part of user space.
  • Include program data, user stack area, and programs that may be modified.

User Program

  • The instructions to be executed.

System Stack

  • Each process has one or more LIFO stacks associated with it.
  • Used to store parameters and calling addresses for procedure and system calls.

Process Control Block

  • Needed by the OS to control processes.

Question 86

Operating System

Question

MCQ▾

The redirection operators and

Choices

Choice (4)

a.

differ: is used for input while is used for output

b.

differ: write to any file while write only to standard output

c.

do the same function

d.

differ: overwrites, while appends

Answer

d.

Explanation

  • ’ redirects the output to file by creating it and if the file already exist it overwrites it without user intimation. A new file is created if a file does not exist.
  • ’ redirects the output to a file by creating it and if the already exist, it is appended.

Question 87

Operating System

Question

MCQ▾

The standard source for standard input, standard output and standard error is

Choices

Choice (4)

a.

The terminal

b.

/usr/you/input, /usr/you/output/, /usr/you/error respectively

c.

/dev/null

d.

Question does not provide sufficient data or is vague

Answer

a.

Explanation

Understanding of Standard Output and Standard Error

The standard source for standard input, standard output and standard error is the terminal.

Standard Output

  • Program sends information to standard output even without knowing.
  • However, the same output can go to a printer, an ordinary file, or the network.

Standard Input

  • Program gets its information from standard input which by is the keyboard.
  • Program never “knows” where the information comes from.
  • Standard input can also come from a file or network.

Standard Error

In addition to standard input and standard output, a running program sends error messages, which by default, the shell directs to the screen.

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