Page 26 - Computer Science Class 11 With Functions
P. 26

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.












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