Page 28 - Computer Science V2.0 Class 11

Ø The main memory of a computer is also known as RAM, which stands for Random Access Memory.
Ø External memory, which is sometimes called backing store or secondary memory, allows permanent storage
of large quantities of data.
Ø RAM is Random access memory that can be read and written and is used for manipulating data during
processing.
Ø The data and instructions are retained in the RAM as long as the computer remains connected to the power
supply. So, RAM is also known as volatile memory.
Ø ROM is a non-volatile memory that stores the data permanently, i.e. the contents are not lost even when the
power supply is turned off.
Ø Various types of ROM are PROM, EPROM, and EEPROM.
Ø The cache memory is a special high speed memory storing the most recently accessed data.

Ø Data Bus is used to transfer data between different components.
Ø Address Bus is used to transfer addresses of memory locations for the CPU to perform read/write operations
in the memory.
Ø Control Bus is used to transfer control signals between various computer components.
Ø A set of programs that performs a useful task is called software.
Ø Software is a set of instructions written to achieve the desired tasks and is mainly categorized as system
software, and application software.

Ø System Software provides basic functionality to operate a computer. Examples of system software are
operating systems, utilities, device drivers, and compilers.

Ø An operating system provides an interface between the users of a computer and the computer hardware so
that they can operate the computer.

Ø A system utility helps in the smooth functioning of the system.
Ø Command-based User Interface, the user interacts with the computer system by typing commands.
Ø Graphical User Interface comprises menus, icons, windows and other such visual components.
Ø Touch User Interface (TUI) enables the users to interact with the computer using human touch.

Ø Voice-based Interfaces take verbal commands.
Ø Application software is a set of programs necessary to carry our operations for a specified application.
Ø General purpose application software is a generic software that caters to the general requirements of many
users.
Ø Customised software is designed to meet the requirements of a client according to their business needs.
Ø A language processor converts a program written in high level language to machine language.

Ø Assembler converts the program written in assembly language to machine language.
Ø A compiler converts a program written in a high-level language to an equivalent program in the computer's
machine language.
Ø Interpreter converts the source code to an executable form and executes it instruction by instruction.

14 Touchpad Computer Science (Ver. 2.0)-XI