[1] System Software-
System software comprises device drivers, operating systems, servers, software components, and programming software (for writing programs through tools such as editors, linkers, debuggers, compilers/interpreters, and others). The most important is the operating system, here we will discuss the operating system.
Operating System-
An operating system handles signals or instructions received from input and output devices, manages memory usage, and control peripherals. Therefore, the operating system is the most important program a computer must run on. DOS (Disk Operating System), Microsoft Windows XP, and Mac OS are some examples of personal computer operating systems. Server-level computers use operating systems such as UNIX and Microsoft Windows Server.
To interact with the computers a user uses a part of the operating system called a user interface. The functions of the user interface are to start application programs, manage secondary storage, such as hard disks, as well as manipulate files and folders, and finally shut down the computer safely. The three principal types of interfaces are-
• Graphical User Interface (GUI)
• Command‐line interface/Character User Interface (CUI)
A graphical user interface is a form of user interface that allows users to interact with electronic devices through graphical icons, menu and an audio indicator such as primary notation. A GUI is a user‐friendly interface that eliminates the need to remember complex computer commands. CUI is a way for users to interact using commands with computer programs. In CUI based computers user interacts using text-based commands. Examples CUIs are MS-DOS and the Windows Command Prompt.
Functions of an Operating System-
Managing computer resources- The operating system manages all files on a computer. It keeps tracks of the locations where programmes and data are stored within the computer’s memory.For example, if you work on a document in Excel and you want to print the document, you just press the print button on the toolbar. Excel will direct the operating system to select a printer to print the document.
Managing files and memory- The operating system manages all files on a computer. It keeps tracks of the locations where programmes and data are stored within the computer’s memory. For example, when you open a file that has been saved to the hard drive you are first instructing the computer to find the file and then to open it.
Maintaining security- In networks and larger computers, each user is given a user name or ID and password to gain access to the computer system. The operating system keeps a register of all these names so that only persons with valid usernames and passwords can access the system. This prevents access by hackers and unauthorised persons.
Managing tasks- A computer can perform many tasks simultaneously. One way of doing this is multi‐tasking – the ability of the computer to run more than one programme at the same time. For example, a user can listen to music on his/her computer while typing a document or typing an e‐mail while another e‐mail is being sent.
Providing a user interface- Many operating systems functions are never apparent on the computer’s display screen. What you see on the screen is called the user interface. The interface helps the user to interact with the computer.
Types of operating systems-
[a] Batch operating system-
It is a type of operating system where users directly do not interact with the computer system. The user prepares his/her job in the form of batch (a group of tasks) and submits it to the computer for processing. To speed up processing, jobs with similar needs are batched together and run as a group. The batch operating system have some difficulties- lack of interaction between the user and the job, slower speed of the mechanical I/O devices than the CPU, difficulty in providing the desired priority, etc.
[b] Time-sharing operating systems-
Time-sharing is a technique that enables many people located at various terminals to use a particular computer system at the same time. Time-sharing or multitasking is a logical extension of multiprogramming. The processor's time which is shared among multiple users simultaneously is termed as time-sharing. The main difference between Multiprogrammed Batch Systems and Time-Sharing Systems is that in the case of Multi programmed batch systems, the objective is to maximize processor use, whereas, in Time-Sharing Systems, the objective is to minimize response time.
[c] Distributed Operating System–
The distributed operating systems are referred to as loosely coupled systems or distributed systems. These system’s processors differ in size and function. The major benefit of working with these types of operating system is that it is always possible that one user can access the files or software which are not present on his system but some other system connected within this network i.e., remote access is enabled within the devices connected in that network.
[d] Network operating System-
A Network Operating System runs on a server and provides the server the capability to manage data, users, groups, security, applications, and other networking functions. The primary purpose of the network operating system is to allow shared file and printer access among multiple computers in a network, typically a local area network (LAN), a private network, or to other networks,
[e] Real-time operating System-
A real-time system is defined as a data processing system in which the time interval required to process and respond to inputs is so small that it controls the environment. The time taken by the system to respond to an input and display of required updated information is termed as the response time. A real-time operating system must have well-defined, fixed time constraints, otherwise, the system will fail.
[2] Application Software-
Computer software is basically programs and procedures intended to perform specific tasks on a computer system. The user directly deals with the application software for a specific purpose. The application software (program) also called end-user programs or apps can be a single program or a group of small programs often referred as an application suite. Some examples of application software are-
• Word processing software (example- MS Word, WordPad, and Notepad).
• Database software (example- Oracle, MS Access, MY SQL, etc).
• Spreadsheet software (example- Apple Numbers, Microsoft Excel, Open Office).
• Multimedia software (example- Real Player, Media Player, VLC player, etc).
• Presentation Software (example- Microsoft PowerPoint, Keynotes, open office, etc).
• Enterprise Software (example- Customer relationship management system, Hospital Management Software, etc).
• Information Worker Software (example- Documentation tools, resource management tools, etc).
Utility programs-
Utility programs, as the name suggests not only help in executing various crucial tasks for the operating system but also help in the overall maintenance of the computer system. Operating systems such as Windows, macOS, and Linux come with their own set of utility programs to maintain and execute different utility functions such as formatting, compressing, scanning, exploring, and much more. Utility programs also assist with the management of computer functions, resources, and files. Some common tasks performed by utility programs are- Disk Defragmentation, Disk Clean-up, File Management, Compression, Disk Management, Antivirus, Firewall, etc.