Basic CS [3i Infotech Placement]: Sample Questions 6 - 7 of 243

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Question 6

Basic CS
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Describe in Detail

Essay▾

What is virtual channel?

Explanation

  • An entity is represented or defined by set of attributes.
  • Attributes are the properties used to describe an entity.

Types of Entity:

  • Strong Entity Types
  • Recursive Entity Types
  • Weak Entity Types
  • Composite Entity Types or Associative Entity Types
  • SuperType and SubType Entities

Different Entity Type in ER Diagram

Table of Different Entity Type in ER Diagram
Entity Type in Image
Entity
Strong Entity Type
Strong Entity Type
Weak Entity Type
Weak Entity Type
Recursive Entity Type
Recursive Entity Type
Composite Entity Type
Composite Entity Type (or)

Associative Entity

Subtypes and Supertypes
Subtypes and Supertypes

Question 7

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Describe in Detail

Essay▾

What are local and global page replacements?

Explanation

Global and Local Allocation

Local Replacement

  • An incoming page is brought in only to the relevant process address space.
  • Considers every process individually.
  • Adjusts memory allocation according to relative importance of each process to improve performance.
  • Local replacement is done for one process and one process only.
  • Does not allow a process to replace page in another processes memory

Global Replacement

  • Policy allows any page frame from any process to replace any other page (even page of another process) .
  • The latter is applicable to variable partitions model only.
  • Applied to every process unit.
  • Ignore characteristics of individual process behaviour- aims to achieve the best overall performance.

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