Define Operating system
An operating system is a powerful, and usually large, program that controls and manages the hardware and other software on a computer. All computers and computer-like devices have operating systems, including laptop, tablet, desktop, smartphone, smartwatch, and router etc., often abbreviated as OS.The following are examples of services provided by an operating system:
·
Context
Switching & Scheduling, which allocate a process CPU time to execute its
instructions.
·
Memory
Management, which deals with allocating memory to processes.
·
Inter-process
Communication, which deals with facilities to allow concurrently running
processes to communicate with each other.
·
File
Systems, which provide higher level files out of low level unstructured data on
a disk.
·
High
level I/O facilities, which free a process from the low-level details of
interrupt handling.
Differentiate between paging and segmentation:
In paging, memory is divided in to equal size
segments called pages whereas
memory segments could vary in size (this is why
each segment is associated
with a length attribute). Sizes of the segments are
determined according to the
address space required by a process, while address
space of a process is divided
in to pages of equal size in paging. Segmentation
provides security associated
with the segments, whereas paging does not provide
such a mechanism.
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