Functions of Operating System
Following functions are provided by an operating system for the convenience of users
- Process Management: It is a process by which an operating system can control the planning, monitoring, and performance of a CPU. A process is the basic unit of execution in the operating system.
- Memory Management: It is a process of controlling and coordinating computer memory. It ensures that all processes can access their memory or not.
- File Management: It is the main function of the operating system. It manages all data files in a computer system.
- Device Management: It is a process of managing the operation and maintenance of input/output devices. It also facilitates the interface between all the connected devices.
Types of Operating System
Types of operating systems are as follows
- Batch Processing Operating System: In this operating system, several jobs are put together and executed as a group. This operating system is responsible for scheduling the jobs according to priority and the resource required. e.g. Unix.
- Single User Operating System: It is a type of operating system which allows only one user at a time. The operating system for a personal computer (PC) is a single-user OS. They are designed to manage one task at a time. e.g. MS-DOS, Windows 9X.
- Multi User Operating System: This OS allows multiple users to access a computer system concurrently. It is used in computer networks that allow the same data and applications to be accessed by multiple users at the same time. e.g. VMS.
- Multi-Tasking Operating System: In this operating system, more than one process can be executed concurrently. It also allows the user to switch between the running applications. e.g. Linux, Unix, Windows 95. Multi-tasking OS is further classified into two types
- Preemptive Multitasking OS: It is a type of multitasking that allows computer programs to share the operating system and underlying hardware resources.
- Cooperative Multitasking OS: It is the simplest form of multitasking. In it, each program can control the CPU for as long as it needs it.
- Time Sharing Operating System: This operating system allows multiple programs to simultaneously share computer resources. It provides to each process to be run on. e.g. Mac OS.
- Real-Time Operating System (RTOS): These operating systems are designed to respond to an event within a predetermined time. They are often used in applications such as flight reservation systems, military applications, etc. is types of operating system increase the availability and reliability of the system. e.g. Linux etc. There are two types of real-time operating system.
- Hard Real-Time OS: In this RTOS, all the tasks are required to be completed within the specified time limits.
- Soft Real-Time OS: In this RTOS, all the tasks are not required to be completed within the specified time limits.
User Interface
The user interface is one of the most important parts of any operating system. It allows users to easily access and communicate with the applications and the hardware. The user can interact with the computer by using mainly two kinds of interface
- Graphical User Interface (GUI): It is a computer program that enables a person to communicate with a computer through the use of symbols, visual metaphors, and pointing devices. It is best known for its implementation in Apple products. The first graphical user interface was designed by Xerox Corporation in the 1970s. GUIs can be found in handheld devices such as MP3 players, portable media players, gaming devices, etc.
- Character User Interface (CUI): It is also known as Command Line Interface (CLI). CUI is a mechanism of interacting with a computer system or software by typing, commands to perform specific tasks. CUI only uses text types one after another just as commands used in MS-DOS.
Booting: Booting is starting up a computer or computer appliance until it can be used. It can be initiated by hardware such as a Start button or by software command. There are two types of booting
- Cold Booting: When a computer is turned ON after it has been completely shut down.
- Warm Booting: When a computer is restarted by pressing the combination of Ctrl + Alt + Del keys or by restart button.
Some Important Operating Systems
Some popular operating systems are as follows
- UNIX: The first version of Unix was developed in 1969 by Ken Thompson and Dennis Ritchie. It is primarily used for a server rather than a workstation and should not be used by anyone who does not understand the system.
- Apple Macintosh (Mac OS): It was introduced in January 1984 by Steve Jobs and was initially named system software, which was later renamed Mac OS.
- Linux: The first Linux Kernel was released in September 1991 by Linus Torvalds. It is open-source software. Linux is similar to Unix in operations. It is difficult to understandanyone.
- Microsoft Windows: It is an operating system, based on GUI, developed by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 in response to the growing interest in GUIs.
Mobile Operating System
This OS operates on Smartphones, Tablets and Digital Mobile devices. It controls mobile devices and its design supports wireless communication and different types of mobile applications. It has built-in support for mobile multimedia formats.
Some popular mobile operating systems are as follows
- Android: It is a mobile OS developed by Google, which is based on Linux (Main part of operating system). It is basically designed for touch screen mobile devices like Tablets, Smartphones etc. Now-a-days, it is most common used in mobile phones. The latest version of Android is Pie which was released on 6th August, 2018.
- Symbian: It is the OS developed and sold by Symbian Ltd. It is an open source mobile OS designed for Smartphones. It has been used by many major handset manufacturers including Motorola, Nokia, Samsung, Sony etc. The latest version of Symbian is Nokia Belle which was released in October 2012.
- iOS: It is the popular mobile operating system developed by Apple Incorporation. This operating system is commonly used in Apple iPhone, iPod Touch, iPad etc. The latest version of iOS is iOS 11.4.1 which was released on 9th July, 2018.
- BlackBerry: It is the most secure operating system used in leading Smartphones developed by BlackBerry company. It also supports WAP 1.2. The latest version of BlackBerry is BlackBerry OS 10.3.3 which was released in 2016.
MS-DOS (Microsoft-Disk Operating System)
The DOS OS was developed by Microsoft in 1980 for micro computers. MS-DOS was the first operating system that run on PC developed by IBM corporation in 1981. DOS is a single-user operating system. It is the only operating system that can be loaded into the main memory of the computer using a single disk.
Structure of DOS
There are four essential programs associated with the control of the computer and the way it interacts with them.
- The Boot Record includes loading the operating system into the main memory. It is the main program of MS-DOS.
- The Basic Input/Output System (BIOS. sys) It provides an interface between the hardware and programs.
- The MSDOS. sys Program It is a collection of program routines and data tables that provides high level programs such as application programs.
- The Command.com Program provides a standard set of commands that gives users access to file management, configuration, and miscellaneous functions.
Configuration of DOS
Config. sys, Autoexec. bat and files provide the environment for the computer to set commands.
- Config. Sys: It adjusts the system according to commands.
- Autoexec.bat: When the system is powered on, this file executes automatically on the command line.
Types of MS-DOS Commands
There are two kinds of MS-DOS command,
Internal and External.
- Internal Commands: These commands are automatically loaded into main memory when the booting process gets completed. e.g. DATE, TIME, VER, VOL, DIR, COPY, CLS, etc.
- External Commands: These commands require external files to be loaded in the computer to run. e.g. Checking disk, comparing disk, formatting, etc.
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