3.2. The function of the
operating system (OS)
OS - hidden software.
Purpose OS.
Supervisor program, resident
3.2. The function of the operating system (OS)
1. Lead-in activity: What is an operating system and what is its purpose? Where is an operating
system stored and how is it transferred to internal memory?
List some of the tasks typically performed by an operating system.
2. Read the text and try to find an answer to the following questions:
1 Where is an operating system stored and how is it transferred to internal memory?
2 What are the main functions of an operating system?
3 Why is the supervisor program the most important operating system program?
4 What is the difference between resident and non-resident programs?
What is the OS (or the hidden software)?
The hardware needs software to make it work. Without an operating system, a computer is useless.
Are we talking about applications software.
An operating system is the most important software that runs on a computer. It manages the computer's memory, processes, and all of its software and hardware.
It also allows you to communicate with the computer without knowing how to speak the computer's language. An operating system is a set of programs that lies
between applications software and the computer hardware. It has to be "loaded" into the computer's storage (such as the hard drive or memory). Once the
software has loaded, the computer is able to execute the software. The most important program in the operating system, the program
that manages the operating system, is the supervisor program, most of which remains in memory and is thus referred to as resident.
The supervisor controls the entire operating system and loads into memory other operating system programs (called nonresident)
from disk storage only as needed.
An operating system has three main functions: manage the computer's resources, such as the central processing unit, memory, disk
drives, and printers, establish a user interface, and execute and provide services for applications software. Much of the work of an
operating system is hidden from the user. In particular, the first listed function, managing the computer's resources, is taken care of
without the user being aware of the details. Furthermore, all input and output operations, although invoked by an applications
program, are actually carried out by the operating system.
Multitasking is the capability of some operating systems, such as Windows, to simultaneously perform two or more tasks. This means
that while you are printing a document, you can, for example, work on another document or play a computer game. Although the
tasks appear to be performed simultaneously, they are actually interleaved, that is the operating system divides the processing time
among the tasks to be performed. For example, it will process the document to be printed for a quarter of a second. While the
document is being printed, it attends to the document that you are working on or on the game that you are playing. Since multitasking
is performed at very high speeds, it becomes virtually unnoticeable.
3. Read the text again and put the terms – “Operating System”, “User”, “Hardware” and “Application software” to their proper place at the diagram:
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