1. A computer consists of five functionally independent main parts

2. Basic Functional Units of a Computer Input – accepts coded information from human operators, from electromechanical devices (such as keyboards), or from other digital medium via digital communication lines. The information received is either stored in the memory or immediately used by the arithmetic and logic unit (ALU) to perform the desired operations. The results are sent back out through the output medium. All actions are coordinated through the control unit.

3. A Simple Computer consists of a Processor (CPU-Central Processing Unit), Memory, and I/O Memory Input Output Arithmetic And Logic Unit Control Unit I/O Processor Or CPU

4. Block Diagram for a Simple Computer

5. The Information Categorized as either instructions or data Instructions (or machine instructions) are explicit commands that –Govern the transfer of information within a computer as well as between the computer and its I/O devices. –Specify the arithmetic and logic operations to be performed.

6. Programs A list of instructions that performs a task is called a program. Usually the program is stored in memory. The program fetches the instructions from memory, one after another, and performs the desired operations. The computer is completely controlled by the stored program, except for possible interruption by an operator or by I/O devices connected to the machine. Data are numbers and encoded characters that are used as operands by the instructions.

7. Data Numbers and encoded characters that are used as operands by the instructions. We will break from looking at the functional units to look at data representations…..