Page 23 - Computer Science V2.0 Class 11

The read or write instructions are communicated through the control bus. Similarly, to write data into the memory,
the CPU places the data on the data bus, and the address of the memory location where the data has to be written is
placed on the address bus. Once this is done, a control signal is issued to write the data from the CPU to the designated
memory location.

Give two examples of the following:
1. The output devices that generate sound as output.
2. The devices that produce a hard copy output.
3. Secondary memory storage.
4. Types of bus.

1.5 Software

Recall that a sequence of instructions given to a computer is called a program. The computer manufacturer provides
several useful programs that help the end user to use the computer conveniently. A set of programs that performs a
useful task is called software. Some examples of software are Microsoft Office, Adobe Photoshop, Media player, and
Python.
A software developer may develop a proprietary software and charge its users a one-time price or regular fee. The
source code for proprietary software is not available to its users. Examples of proprietary software include Microsoft
Windows 11, Adobe Photoshop, and Microsoft Office. However, sometimes a developer may make source code
available to its users. A software whose source code is publicly available is called open-source software. Ubuntu,
Libre Office and Gimp are examples of open-source software (OSS). Most of the opensource software are available
free for use, although in some cases, open source software may be chargeable. In addition, basic version of some
proprietary software, such as Skype and Adobe Reader, is available for use free of charge, but the users who intend to
use advanced features of Skype and Adobe must pay for their usage.

1.5.1 Types of Software

Depending on its use, the software is broadly categorised into two categories:
System Software
Application Software

Types of Software

System Software Application Software

- Operating System - General or Packaged
- Device Driver Software
- Language Processor - Customized Software
- Utility Software

Fig 1.8: Types of Software

Computer Fundamentals 9