3i Infotech Placement: Sample Questions 391 - 392 of 1245

Glide to success with Doorsteptutor material for competitive exams : get questions, notes, tests, video lectures and more- for all subjects of your exam.

Question 391

Edit

Describe in Detail

Essay▾

What is Process migration?

Explanation

Process, Virtual Machine, and OS Migration
  • Migration is a form of process management- process is moved from one computing environment to another.
  • Involves transfer of sufficient state of process from one machine to the target machine.
  • Enables dynamic load distribution, fault resilience, eased system administration, and data access locality.

Two Types of Process Migration

  • Non-pre-emptive process migration:
    • Takes place before execution of the process starts.
    • Relatively cheap.
  • Pre-emptive process migration:
    • Process is pre-empted, migrated and continues processing in a different execution environment.
    • Relatively expensive- involves recording, migration and recreation of the process state.

Steps Involved in Process Migration

  • Freezing the process on source.
  • Transferring the process address space from source to destination.
  • Restarting the process on destination
  • OS forward messages to the new destination for the migrant process- handling communication between cooperating processes.

Question 392

Question

MCQ▾

What SYSTEM VARIABLE is used to refer DATABASE TIME?

Choices

Choice (4)

a.

$ $ dbtime $ $

b.

$ $ time $ $

c.

$ $ datetime $ $

d.

Question does not provide sufficient data or is vague

Answer

a.

Explanation

  • $ $ dbtime $ $ SYSTEM VARIABLE is used to refer DATABASE TIME.
  • $ $ dbtime $ $ retrieves the current time for local datatbase.
  • Database time is the total time by the all user processes that are actively working in the database.
  • Variable $ $ dbtime $ $ can be used to design a default value for a text item using the initial value properties.
  • When connect to a remote database it may be in a different time.

Syntax of system variable:

$ $ dbtime $ $

Developed by: