Software's

What is software ?????

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.

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

Applications software's

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.

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.

SYSTEM SOFTWARE'SSystems 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!

3. Applications software

2. Utility softwareThe 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.

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

• 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.

• 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. 

• 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.

• 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.

• 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.

• 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.

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.

• Virus CheckerA 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.

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THIS P.P.T.

MADE BY: SHASHANK GARG

CLASS: XI- A