An operating system is a program that acts as an interface between the user and the computer hardware and controls the execution of all kinds of programs.
Operating system (OS) manages all of the software and hardware on the computer. Most of the time, there are several different computer programs running at the same time, and they all need to access your computer’s central processing unit (CPU), memory, and storage. The operating system coordinates all of this to make sure each program gets what it needs.
Following are some of important functions of an operating System.
- Memory Management
- Processor Management
- Device Management
- File Management
- Control over system performance
- Job accounting
- Error detecting aids
- Coordination between other software and users
Memory management refers to management of Primary Memory or Main Memory. Main memory is a large array of words or bytes where each word or byte has its own address.
Main memory provides a fast storage that can be accessed directly by the CPU. For a program to be executed, it must in the main memory. An Operating System does the following activities for memory management −
- Keeps tracks of primary memory, i.e., what part of it are in use by whom, what part are not in use.
- In multiprogramming, the OS decides which process will get memory when and how much.
- Allocates the memory when a process requests it to do so.
- De-allocates the memory when a process no longer needs it or has been terminated.
In multiprogramming environment, the OS decides which process gets the processor when and for how much time. This function is called process scheduling. An Operating System does the following activities for processor management −
- Keeps tracks of processor and status of process. The program responsible for this task is known as traffic controller.
- Allocates the processor (CPU) to a process.
- De-allocates processor when a process is no longer required.
An Operating System manages device communication via their respective drivers. It does the following activities for device management −
- Keeps tracks of all devices. Program responsible for this task is known as the I/O controller.
- Decides which process gets the device when and for how much time.
- Allocates the device in the efficient way.
- De-allocates devices.
A file system is normally organized into directories for easy navigation and usage. These directories may contain files and other directions.
An Operating System does the following activities for file management −
- Keeps track of information, location, uses, status etc. The collective facilities are often known as file system.
- Decides who gets the resources.
- Allocates the resources.
- De-allocates the resources.
Other Important Activities
Following are some of the important activities that an Operating System performs −
- Security − By means of password and similar other techniques, it prevents unauthorized access to programs and data.
- Control over system performance − Recording delays between request for a service and response from the system.
- Job accounting − Keeping track of time and resources used by various jobs and users.
- Error detecting aids − Production of dumps, traces, error messages, and other debugging and error detecting aids.
- Coordination between other software and users − Coordination and assignment of compilers, interpreters, assemblers and other software to the various users of the computer systems.
Since the operating system serves as a computer’s fundamental user interface, it significantly affects how you interact with the device. Therefore, many users prefer to use a specific operating system. For example, one user may prefer to use a computer with OS X instead of a Windows-based PC. Another user may prefer an Android-based smartphone instead of an iPhone, which runs the iOS.
When software developers create applications, they must write and compile them for a specific operating system. This is because each OS communicates with the hardware differently and has a specific application program interface, or API, that the programmer must use. While many popular programs are crossplatform, meaning they have been developed for multiple OSes, some are only available for a single operating system. Therefore, when choosing a computer, make sure the operating system supports the programs you want to run.
Types of Interfaces in Operating Systems
There are five main types of user interface:
- command line (cli)
- graphical user interface (GUI)
- menu driven (mdi)
- Touchscreen Graphical User Interface.
- natural user interface (NUI)
command line (cli)
Command line interfaces are the oldest of the interfaces discussed here. It involves the computer responding to commands typed by the operator. This type of interface has the drawback that it requires the operator to remember a range of different commands and is not ideal for novice users.
Graphical user interfaces (GUI) are sometimes also referred to as WIMP because they use Windows, Icons, Menus and Pointers. Operators use a pointing device (such as a mouse, touchpad or trackball) to control a pointer on the screen which then interacts with other on-screen elements. It allows the user to interact with devices through graphical icons and visual indicators such as secondary notations. The term was created in the 1970s to distinguish graphical interfaces from text-based ones, such as command-line interfaces. However, today nearly all digital interfaces are GUIs. The first commercially available GUI, called “PARC,” was developed by Xerox. It was used by the Xerox 8010 Information System, which was released in 1981. After Steve Jobs saw the interface during a tour at Xerox, he had his team at Apple develop an operating system with a similar design. Apple’s GUI-based OS was included with the Macintosh, which was released in 1984. Microsoft released its first GUI-based OS, Windows 1.0, in 1985.
A menu driven interface is commonly used on cash machines (also known as automated teller machines (ATM’s), ticket machines and information kiosks (for example in a museum). They provide a simple and easy to use interface comprised of a series of menus and sub-menus which the user accesses by pressing buttons, often on a touch-screen device. Preferably, if one has knowledge on UML modeling, it can be a good example when designing the architecture of the machine.
touch screen user interface
A touch user interface is a computer-pointing technology based upon the sense of touch (haptics). When the term touch UI is related to the touchscreen, we are referring to multi-touch technology. Most of the apps and games that use this technology have optimized for touch UI due to the large use of touchscreens.
natural user interface (NUI)
A natural user interface (NUI) is a system for human-computer interaction that the user operates through intuitive actions related to natural, everyday human behavior. A NUI may be operated in a number of different ways, depending on the purpose and user requirements.