Central Processing Unit

Components of the CPU:-

Arithmetic and Logic Unit (ALU): processes the data in the registers according to instructions issued by the control unit. Performs arithmetic (addition, subtraction, etc..) and logical (comparison) operations.

Registers: provides temporary storage for data and instructions. It handles instructions and data at 10 times the speed of cache memory. Registers facilitate the movement of data and instructions between RAM, the control unit and the ALU.


Internal CPU interconnection: some mechanism that provides for communication among the control unit, ALU, and registers.

Control Unit: controls the operation of the CPU and hence the computer. Interprets instructions, moves data to/from memory and registers, instructs ALU to perform certain operations, increments instruction pointer, etc. During program execution, instructions in a program are moved from the RAM into the control unit, where it is decoded and interpreted by the decoder.

Flags: 1-bit memory, or 1-bit registers and hold information on what has recently happened in the CPU.

Cache Memory:-
Small fast memory that improves CPU’s efficiency. Increases computer throughput, and is a high-speed holding area for program instructions and data. It holds only instructions and data that are likely to be needed by the CPU. While programs are running on the computer, the same data or instructions might be needed frequently. In such cases, the processor first checks the cache memory for the data or instructions, thereby reducing the need for frequent access to the RAM and speeding up the processing.


System Unit:-
The system unit is the case that holds the power supply, storage devices, and the circuit boards, including the main circuit board (also called the “mother board”), which contains the microprocessor.


System Unit:-
Power Supply
Storage Devices
Circuit Boards

Computer Components:-

System Buses:-

A BUS is an internal communications path consisting of a number of lines connecting the system components.

Control bus– The control bus synchronizes system events like memory access, system interrupts, I/O, etc.

Address bus– Source and destination addresses are sent over the address bus to identify a particular location in memory or input/output port.

Data bus– Two way path for transferring data and instructions in and out of the microprocessor.