Basic CS-Operating System [3i Infotech Placement]: Sample Questions 55 - 56 of 89

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Question 55

Operating System
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Describe in Detail

Essay▾

Which header file should you include if you are to develop a function, which can accept variable number of arguments?

Explanation

  • stdarg. h- it defines a variable type va_list and three macros which can get the arguments in a function when the number of arguments are not known i.e.. variable number of arguments.
  • A function of variable arguments is defined with the ellipsis (, … .) at the end of the parameter list.

Below are the argument list function:

  • va_arg

    Fetch argument from variable argument list.

  • va_end

    End processing of variable argument list.

  • va_start

    Start processing of variable argument list.

The Argument List Function

Question 56

Operating System

Describe in Detail

Essay▾

What are the stipulations of level security?

Explanation

Level security provides for:

Discretionary Access Control:

  • Object owner specifies the subjects that can access the object.
  • Method called discretionary as the control of access is based on the discretion of the owner.
  • Allows each user to control access to their own data.
  • Default access control mechanism for desktop operating system.

Identification and authentication:

  • Ensures subject is entity it claims to be.
  • Provides use of a username or account number.
  • Requires authentication providing second piece to the credential- password, cryptographic key, personal identification number.

Auditing:

  • Audit performed by Risk Management & Audit Services provides comprehensive examination of a targeted system.
  • Consists of an evaluation of the components.

Resource reuse:

  • Ensures that resources likes CPU or tape transport are not rendered useless by use.
  • Magnetic disk or tape can be use often indefinitely as “reusable resource” .

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