Page 112 - DCAP103_Principle of operating system

Unit 3: Process Management-II

3.10 Keywords Notes

Process Management: Process management is a series of techniques, skills, tools, and methods
used to control and manage a business process within a large system or organization.

Threads: A thread is a single sequence stream within in a process.
Process: A process is an instance of a computer program that is being executed. It contains the
program code and its current activity. Depending on the operating system (OS).
Kernel: The kernel is the central component of most computer operating systems; it is a bridge
between applications and the actual data processing done at the hardware level.

Context Switch: A context switch is the computing process of storing and restoring state (context)
of a CPU so that execution can be resumed from the same point at a later time.

Multitasking: Multitasking is the ability of an operating system to execute more than one
program simultaneously.
The Cost of Context Switching: Context switching represents a substantial cost to the system
in terms of CPU time and can, in fact, be the most costly operation on an operating system.
BIOS: The BIOS software is built into the PC, and is the first code run by a PC when powered
on (‘boot firmware’). The primary function of the BIOS is to load and start an operating
system.
CPU Scheduling: CPU scheduling algorithms have different properties, and the choice of a
particular algorithm may favor one class of processes over another.

Scheduling Algorithm: A scheduling algorithm is the method by which threads, processes or data
flows are given access to system resources (e.g. processor time, communications bandwidth).

3.11 Review Questions

1. What is a thread? Describe the differences among short-term, medium-term, and long-term
scheduling.
2. Provide two programming examples in which multi-threading does not provide better
performance than a single-threaded solution.
3. Describe the actions taken by a thread library to context switch between user-level threads.

4. Under what circumstances does a multithreaded solution using multiple kernel threads
provide better performance than a single-threaded solution on a single-processor system?
5. Which of the following components of program state are shared across threads in a multi-
threaded process?
(a) Register values (b) Heap memory

(c) Global variables (d) Stack memory
6. Can a multi-threaded solution using multiple user-level threads achieve better performance
on multi-processor system than on a single-processor system?

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