Page 64 - DCAP103_Principle of operating system

Unit 2: Process Management-I

Notes
1. Write an Algorithm for PCB concept.
2. Give the step for intercrosses communication.
Self Assessment

Fill in the blanks:
5. Any process that shares data with other processes is a ....................... process.
6. Message sent by a process can be of either fixed or ....................... size.

7. A ....................... is associated with more than two processes.
8. A ....................... owned by the operating system is independent.
True or False:

9. The Mach kernel supports the creation and destruction of multiple task.
10. Window 2000 uses two types of message passing techniques over a port.

2.6 Summary

• A process is a sequential program in execution. A process migrates between the various
scheduling queues throughout its lifetime.
• The operating system must select, for scheduling purposes, processes from these queues
in some fashion.
• The selection process is carried out by the appropriate scheduler.

• Switching the CPU to another process requires saving the state of the old process and
loading the saved state for the new process. This task is known as a context switch. The
context of a process is represented in the PCB of a process; it includes the value of the
CPU registers, the process state and memory-management information.
• A mailbox can be viewed abstractly as an object into which messages can be placed by
processes and from which messages can be removed.
2.7 Keywords

Buffering: A buffer is a temporary storage location for data while the data is being transferred.
Context Switch: A context switch (also sometimes referred to as a process switch or a task switch)
is the switching of the CPU (central processing unit) from one process or thread to another.
Cooperating Processes: Processes can cooperate with each other to accomplish a single task.
Cooperating processes can:
• Improve performance by overlapping activities or performing work in parallel.
• Enable an application to achieve a better program structure as a set of cooperating processes,
where each is smaller than a single monolithic program.
CPU Registers: The central processing unit (CPU) contains a number of memory locations
which are individually addressable and reserved for specific purpose. These memory locations
are called registers.

‘Inter-process Communication’ (IPC): In computing, ‘Inter-process communication’ (IPC) is
a set of techniques for the exchange of data among multiple threads in one or more processes.

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