Operating System

 

Operating System

 

An operating system (OS) is software that communicates with the hardware and allows other programs to run. It is comprised of system software, or the fundamental files your computer needs to boot up and function. Every desktop computer, tablet, and smartphone includes an operating system that provides basic functionality for the device. Common PC operating systems include Windows, Mac OS X, Linux, etc.

 

System Software

 

System software refers to the files and programs that make up the computer's operating system. System files include libraries, system services, hardware drivers, system preferences, and other configuration files. The programs that are part of the system software include assemblers, compilers, file management tools, system utilities, and debuggers.

 

Application software

 

Application software is the programs that perform specific tasks. Theses may include e-mail, word processors, spreadsheet, database systems, games, etc. The application programs run on top of the system software.

 

Functions of an operating system:

• Memory management

o  The OS allocates memory to each job or application according to their sizes.

• Resource allocation and scheduling

o  The OS is responsible for allocating processing time, memory and input-output resources to each program and schedules them in order to make the best use of the computer’s resources.

• Interrupt handling

o  The OS is responsible for detecting any interrupt signals such as a printer sending a message that it is out of paper so that the processor will be allocated to the device that sent the interrupt.

• File Management

o  The OS find a free space on disk for files like word or spreadsheet documents and hold their information such as file type, size, access rights, etc..

 

Types of operating systems:

• Real
• Batch
• Multi user and single user
• Multi-tasking and single tasking

Computer Architecture Layers

 

 

In the diagram above, the operating system is responsible to provide a platform or interface for the application software to run. The diagram also shows how the operating system provides an interface between the application software and the hardware.