Download Operating System Functions

Unit A451:
Computer systems and programming
Section 3: Software
1 – Intro to software
Section Objectives
Candidates should be able to:
(a) Understand the basic functions of an operating system
(b) Explain the need for the following functions of an operating
system: memory management, peripheral management, multitasking and security
Operating Systems
•Operating Systems are the core software that
allow users to interact with and use computers.
•They are essential in order to make the
hardware inside our computers function
correctly.
SOFTWARE AND OPERATING SYSTEMS
Functions of an Operating System
•User Interfaces
•The operating system provides a way for
us to interact with the hardware and
software.
•This is known as an _ _ _ _ _ _ _ _ _
SOFTWARE AND OPERATING SYSTEMS
Functions of an Operating System
•User Interfaces
•The operating system provides a way for
us to interact with the hardware and
software.
•This is known as an Interface
SOFTWARE AND OPERATING SYSTEMS
Functions of an Operating System
•User Interfaces
•Recap
•MS-DOS was an early operating system
that enabled a user to type instructions
for the computer to carry out.
•What is this type of interface known as?
SOFTWARE AND OPERATING SYSTEMS
Operating Systems
This is known as a Command Line Interface
SOFTWARE AND OPERATING SYSTEMS
Functions of an Operating System
•User Interfaces
•Recap
•What were the other 2 types of interface
known as?
SOFTWARE AND OPERATING SYSTEMS
Menu Driven Interface
SOFTWARE AND OPERATING SYSTEMS
Graphic User Interface
SOFTWARE AND OPERATING SYSTEMS
Functions of an Operating System
•An operating system ensures our
computer runs as expected. To do this it
performs a number of tasks and has a
number of vital functions in computer
systems.
SOFTWARE AND OPERATING SYSTEMS
Functions of an Operating System
•These roles include
•Providing an interface
•Memory Management
•Peripheral Management
•Multi-Tasking
•Security
SOFTWARE AND OPERATING SYSTEMS
Memory Management
•You computer only has a limited amount of
Memory (for example 4gb)
•The operating system has something built in
known as a memory manager.
•When you open, and are working on an
application it is stored in the RAM (memory)
SOFTWARE AND OPERATING SYSTEMS
Memory Management
•The memory manager is responsible for
removing and adding programs and removing
them when they are no longer needed.
•Without this the RAM would become overloaded
and the computer would no longer be able to
operate.
SOFTWARE AND OPERATING SYSTEMS
Peripheral Management
•Peripherals are any computer hardware
components that are not part of the CPU. This
includes input devices, output devices and
storage.
•When a new peripheral is added, a software
driver is needed to allow the OS to understand
and install the device.
•The OS then allows the PC and all peripherals to
communicate with each other.
SOFTWARE AND OPERATING SYSTEMS
Multi-Tasking
•A computers CPU can only carry out one instruction at
a time, but has many different programs running at
once.
•This is because the OS cleverly (and quickly!) allocates
data to and from the CPU, prioritising the programmes
need data processing before others.
•Because all of this happens in milliseconds, it gives the
impression of all the programs working at the same
time. ‘Multi-Tasking’.
SOFTWARE AND OPERATING SYSTEMS
Security
•The OS provides different levels of user access and
password protection to keep unauthorised users out of
the computer system.
•It decides on file permissions. This determines who
can see certain folders / files and who can alter or
delete them.
•It may also provide backup and recovery routines for
recovering the system in the event of a system failure.
SOFTWARE AND OPERATING SYSTEMS