3i Infotech Papers: Sample Questions 336 - 337 of 1245

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Question number: 336

» Basic CS » Operating System

Essay Question▾

Describe in Detail

What is Process migration?

Explanation

Process, virtual machine, and OS migration.

Process, Virtual Machine, and OS Migration.

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 number: 337

» Database » Oracle

MCQ▾

Question

What SYSTEM VARIABLE is used to refer DATABASE TIME?

Choices

Choice (4) Response

a.

$$dbtime$$

b.

$$datetime$$

c.

$$time$$

d.

All of the above

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:

$$dbtime$$