ppt on softwares

2. Computer software, or simply software, is that part of a computer system
that consists of encoded information or computer instructions, in contrast to
the physical hardware from which the system is built. The term is roughly
synonymous with computer program, but is more generic in scope.
The term "software" was first proposed by Alan Turing and used in this sense
by John W. Tukey in 1957. In computer science and software
engineering, computer software is all information processed by computer
systems, programs anddata.

3. Software can be categorized according to what it is designed to accomplish.
There are two main types of software: systems software and application
software.

4. Application software, or simply applications, are often called productivity
programs or end-user programs because they enable the user to complete tasks
such as creating documents, spreadsheets, databases, and publications, doing
online research, sending email, designing graphics, running businesses, and
even playing games! Application software is specific to the task it is designed for
and can be as simple as a calculator application or as complex as a word
processing application. When you begin creating a document, the word
processing software has already set the margins, font style and size, and the line
spacing for you. But you can change these settings, and you have many more
formatting options available.

5. For example, the word processor application makes it easy to add
color, headings, and pictures or delete, copy, move, and change the
document's appearance to suit your needs.

6. Systems software includes the programs that are dedicated to managing
the computer itself, such as the operating system, file management utilities,
and disk operating system (or DOS). The operating system manages the
computer hardware resources in addition to applications and data. Without
systems software installed in our computers we would have to type the
instructions for everything we wanted the computer to do!

7. 3. Applications software
2. Utility software
The bootstrap loader 1. Operating System
The bootstrap loader is a small but very
important part of the OS which is
permanently stored in ROM.
When the computer is first switched on the bootstrap loader starts to
run.
It checks the RAM and input/output devices to make sure that they
are working and then locates the OS on backing storage, usually on
Hard disk but could be on CD or even a memory stick.
It then loads the OS into RAM and the OS takes over control.

8. The main part of the operating system in
RAM manages the computer and allows
the user to communicate with the
hardware
It has 6 main functions:
• Interpreting User Commands
• File Management
• Memory Management
• Input/output Management
• Managing Processes
• Resource Allocation

9. • Interpreting User Commands
• Interpreting User Commands
• File Management
• Memory Management
• Input/Output Management
• Managing Processes
• Resource Allocation
This part of the operating system accepts
commands (from a keyboard, mouse,
etc) and passes them to the appropriate
parts of the operating system.
If the syntax of the command is not correct then an error message
should be displayed for the user or the command should be ignored.
e.g. clicking the left mouse button on a
blank area of the desktop.

10. • Interpreting User Commands
• File Management
• Memory Management
• Input/Output Management
• Managing Processes
• Resource Allocation
• File Management
This part of the OS manages file
operations and backing storage allocation.
It allocates blocks of data to particular areas on the backing storage
medium. It maintains an index of where all the user's applications
and data are stored so that they can be found when requested.
If you give a command to load a file from disk, the Command
Interpreter will pass this instruction to File Management.

11. • Memory Management
• Interpreting User Commands
• File Management
• Memory Management
• Input/Output Management
• Resource Allocation
• Managing Processes
Memory Management decides where
programs and data are to be placed in
RAM.
It checks to make sure that there is enough free space to store the
new program and data.
It allocates an area of RAM to store the data which the program is
processing. e.g. when you work with Word then you will have a Word
document which also requires RAM space
It allocates an area of RAM to store the program.

12. • Input/output Management
• Interpreting User Commands
• File Management
• Memory Management
• Input/Output Management
• Managing Processes
• Resource Allocation
It is the task of Input/Output
Management to do all the actual data
transfers and issue the appropriate
control signals to the peripheral
devices.
When a file is to be loaded, File Management will pass the
information about the physical location (e.g. Track 10, Sector 4)
to Input/output Management.
Input/output Management has to send the correct signals to the
Hard Disk to tell it to access Track 10, sector 4, read the data and
send it to RAM.

13. • Managing Processes • Interpreting User Commands
• File Management
• Memory Management
• Input/Output Management
• Managing Processes
• Resource Allocation
A process is defined as being “ an
instance of a sequence of code in
execution”
A modern OS will typically have several processes on the go at the
same time. e.g. Operating system, Microsoft Word, printing, virus
checker.
Processes have to share processor time.
The OS has to manage the processes so that they can be carried out
efficiently and effectively.

14. • Resource Allocation
• Interpreting User Commands
• File Management
• Memory Management
• Input/Output Management
• Managing Processes
• Resource Allocation
The competing processes require
access to resources.
Resources include the processor, RAM and Input/Output devices.
If one process is in the middle of sending data to the hard disk then
another process cannot be allowed to start sending its data there too
until the first process has completed its task.
The OS has to manage the resources by controlling how and when
the processes are to be allowed to use them.

15. Utility software consists of programs which are designed to help with
the maintenance of the computer and to ensure sure that it works
correctly and efficiently.
The distinction between utility software and functions of the operating
system is rather blurred as modern operating systems are often bundled
with utility software.
e.g. disk defragmenter, anti-spyware tools, firewall.

16. • Virus Checker
A virus is a program or programming code that
replicates by being copied or initiating its copying
to another program, computer boot sector or
document.
A virus checker examines a computer system to find virus software.
It can be set to examine any type of backing storage media, check email
attachments and files downloaded from the internet.
A good virus checker will constantly work in the background checking
for signs of virus activity.