An operating system is a group of system programs that help a user like you &
me
to interact with the hardware(machine).
An operating systems manages whole of the system by changing the users
instructions in such a form that is easily
understood by the hardware.
The major tasks of an OS can be stated as below:
1. OS manages the data(in the form of files or whatever) on your hard disk
drives & in the Read/Write memory also.
2. OS helps the application programs to run.
3. OS helps to restrict user access to specific hardware & data files.
4. OS helps in running several programs simultaneously on a single machine
with
a single processor.
5. OS is the program that manages all your hardware & software
working.
Examples of OS are : Windows 95, Windows 98, MS-DOS, PC-DOS, OS/2, CP/M,
Windows
NT, Windows 2000,
GNULinux, Unix & many more.
An OS can be seen as a layer of programs in between the application
programs & the hardware as shown below:
Talking about kernel, it is the lowest part of the OS(group of programs) that
resides in the main
memory & handles all your requests & instructions. It contains those parts of
the OS that are
required continuously & helps the other modules of the OS, if required to load
in the main memory
& then to deallocate them from the main memory.
