COMPUTERS Digital Computers Basic Organization A digital computer

COMPUTERS

Digital Computers Basic Organization A digital computer consists of following blocks 1. Central Processing Unit (CPU) / Microprocessor 2. Memory 3. Input devices Clock 4. Output devices 5. Clock Inputs Input devices (Encoder) CPU/ Microprocessor Output devices (Decoder) Outputs Memory CPU (Central Processing Unit) / Microprocessor • It is the most important part of a digital computer. • Carries out all the computations and decision making. • Consists of ALU (Arithmetic & Logic Unit), a number of registers & counters.

Clock • It is a periodic signal applied to CPU in order to coordinate all the operations within the CPU. • It acts as a timing signal, used for sequencing & synchronizing al the operations. Memory • The computation & decision making of CPU is based on specific instructions which tell CPU exactly what to do. • A set of such instructions is called program & is stored in program memory. • CPU fetches the instructions one by one in the given sequence from program memory & executes them. • There is another type of memory called data memory which is used for storing the information that is being processed by CPU. • The result of computation & decision making is stored in data memory. Input devices (encoders) and Output devices (decoders) • Input devices encodes and send data to CPU for processing. • CPU sends data to Output devices where it is decoded for user to understand it.