Categories of OS

The OS can be broadly classified into certain categories. Although one particular OS can fall into more than one category. There are multiuser, multiprocessing, multitasking, multithreading, and real-time operating systems.

A multiuser operating system enables multiple users to run programs simultaneously. This type of operating system may be used for just a few people or hundreds of them. In fact, there are some operating systems that are used to allow thousands of people to run programs at the same time.

A multiprocessing operating system allows a program to run on more than one central processing unit (CPU) at a time. This can come in very handy in some work environments, at schools, and even for some home-computing situations.

A multitasking (or time-sharing) operating systems work a little differently; they make it possible to run more than one program at a time.

A multithreading operating systems allow varied parts of one program to be used simultaneously.

Real-time operating systems are designed to allow computers to process and respond to input instantly. Usually, general-purpose operating systems, such as disk operating system (DOS), are not considered real time, as they may require seconds or minutes to respond to input. Real-time operating systems are typically used when computers must react to the consistent input of information without delay. For example, real-time operating systems may be used in navigation, medical imaging systems, robots, industrial control systems, etc.

 

Exercise 1. Answer the following questions.

 

1. What is an Operating System?

2. What is its function?

3. What role does OS play between the user and the computer hardware? How does it work? What means does it use?

4. What are the categories of OS?

5. Describe briefly each OS category.

 

Exercise 2. Match English words and word combinations with their Russian equivalents.

	share resources	a	универсальная операционная система
	backbone of a computer	b	действовать в качестве интерфейса
	memory allocation	c	без задержек
	to transmit output	d	прикладной программный интерфейс
	act as an interface	e	распределять ресурсы
	system calls	f	постоянный ввод
	application programming interface	g	суть компьютера
	come in very handy	h	отвечать мгновенно
	work environment	i	томографические системы
	respond instantly	j	распределение памяти
	consistent input	k	вызовы системных функций
	without delay	l	передавать выходные данные
	medical imaging system	m	оказаться весьма кстати
	general-purpose OS	n	рабочая среда

 

Exercise 3. Match the words which are very close in their meaning.

	react	a	at the same time
	compatible	b	particular
	control	c	without delay
	use	d	respond
	simultaneously	e	convenient
	handy	f	exploit
	certain	g	monitor
	instantly	h	adaptive

 

Exercise 4. Match the terms on the right with their definitions on the left.

 

	OS which executes processes on several CPU simultaneously is called	a	multitasking
	OS which enables a user to run more than one application at the same time is called	b	real-time
	OS which gives a user an opportunity to exploit different parts of an application without delays is called	c	multiuser
	OS which allows many people to have programs executed at the same time is called	d	multithreading
	when OS is able to react to data or user calls immediately is called	e	multiprocessing

Exercise 5. Match the functions of OS on the right with their definitions on the left.

	OS creates a process by loading a program code from the disk and allocating memory to it.	a	Program execution
	OS handles the allocation and management of memory.	b	Memory management
	OS is in charge of organizing data storage and handling the application program access to files stored on the disk.	c	File management
	OS prevents unauthorized users from accessing the computer system.	d	Security
	OS controls the functionality of all peripherals like a keyboard and printers.	e	Device management
	OS constantly monitors the system for finding bugs and faults	f	Error detecting