What Is an Operating System?
Operating System(OS) is a software program required to manage and operate a computing device. Or we can say an OS is a software that enables applications to interact with a computer’s hardware. In most computer systems, a user requests that the computer perform an act and the OS manages the software and hardware to produce the desired result.
Operating System Goals :
Users have come to expect certain characteristics of operating systems, such as:
efficiency : high throughput as well as low average turnaround time.
robustness : fault tolerant and reliable.
Scalability : ability to use resources as they are added.
extensibility : adapt well to new technologies and perform tasks beyond its original design.
portability : ability to operate on many hardware configurations.
security : prevents users and software from accessing services and resources without authorization.
Interactivity : ability to respond quickly to user actions, or events.
usability : having the potential to serve a significant user base.
Functionalities of OS
UI
An OS offers a UI through a CLI or GUI. CLI provides a text-based interface, whereas GUI provides a visual interface based on icons and symbols. CLI is popular among advanced users. On the other hand, casual or end users mostly use GUI .
Application management
An operating system launches and manages the application execution. It can perform the following services for applications:
A. Determine which application will run in what order and how much time is allocated for each.
B. Handles input/output to and from attached hardware devices(for example, printer, scanner etc.).
C. It can manage how to divide the program so that it runs on more than one processor at a time.
D. It can offload the management of batch jobs etc.
Device Management
An operating system is responsible for identifying, configuring, and providing applications with common access to underlying computer hardware devices. After identifying the device, the OS will install corresponding device drivers that enable the OS and applications to use the devices.
Types of OS
Following are the popular types of OS :
Batch Operating System : a job with a similar type of needs are batched together and run as a group(for example, Payroll System).
Multitasking/Time Sharing OS : it enables people situated at different terminal to use a single computer system at the same time(for instance Multics, Unix).
Real Time OS : time interval to process and respond to inputs is very small for example, air traffic control system.
Distributed OS : many processors located in different machines to provide very fast computation.
Network OS : having the capability to manage data, user, groups, application, and other networking functions(for example UNIX, Linux, Mac OS X).
Mobile OS : especially designed to power smartphones, tablets, and wearables devices.
