Operating System Support - Prime IT Club

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14 Δεκ 2013 (πριν από 3 χρόνια και 5 μήνες)

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Agenda



Operating
System Overview


Objectives of Operating system


Layers of Operating system


Types of Operating System


Scheduling


Memory Management



Operating System Overview



It
the software on a computer that
manages resources.



Under this software all the other
software are being run.



For e.g. Windows7, Linux, Ubuntu etc.


Objectives of Operating System


Convenience: Makes computer more
convenient to use.



Efficiency
: Allows computer system
resources to be used in efficiency.



Ability
to evolve: permit effective
development testing and introduction of
new system function without interfering
with services.


Layers of Computer System

Types of Operating System

Interactive


Late 1940s and 1950s


Program interacts directly with hardware


Two main problem:


Scheduling


Setup Time


Types of Operating System

Batch system


Resident monitor program


Users submit jobs to operator


Operator batches jobs


Monitor controls sequence of events to
process batch


When one job is finished, control returns
to monitor which reads next jobs


Monitor handles scheduling of jobs


Types of Operating System

Single programming (
uni
-

programming)





Only
one job in CPU at a time


Next job starts when previous job cycle
complete.


Types of Operating System

Multi programming


Scheduling


Scheduling

refers to the way processes
are assigned to run on the available
CPUs.



Types of scheduling:


1.
Long
-
term scheduler


2.
Mid
-
term scheduler


3.
Short
-
term scheduler




Long
-
term scheduler


Mid
-
term scheduler


Short
-
term scheduler


Memory Management


Memory management is the act of
managing computer
memory



T
his
involves providing ways to allocate
portions of memory to programs at their
request



Types are given on next slide:

Swapping


This
swapping is method in which the
management of the memory is done by
the swapping of memory and Disk
storage



It is a process to make the operating
system more fast

Partitioning


The simplest scheme for partitioning
available memory is to use fixed
-
size
partitions.



Types:


F
ixed
-
size partition


Variable
-
size
partition

Paging


However
that memory is partitioned into
equal fixed sized chunks of some size
.




Then
the chunks of a program known as
pages could be assigned to available
chunks of
memory.

Virtual Memory


V
irtual
memory

is a memory
management technique developed for
multitasking.




If there
is only one hardware memory
device and this "virtual"
device(
harddisk
)
acts like a RAM
module.