Pronounced as separate letters, CPU is the abbreviation for centralprocessing unit. Sometimes referred to simply as the centralprocessor, the CPU is the brains of the computer where mostcalculations take place. In terms of computing power, the CPU isthe most important element of a computer system.In other words A central processing unit (CPU), also referred to as acentral processor unit, is the hardware within a computer systemwhich carries out the instructions of a computer program byperforming the basic arithmetical, logical, and input/outputoperations of the system.
Block diagram of cpu CPU Control Unit Input Output Device ALU Device Primary Memory Secondary Memory
Basic Components of CPU Control Unit(CU): which controls all the operations of computer system Arithmetic & Logical Unit: which performs all arithmetical & logical operations . Arithmetical operations include addition , multiplication, division, subtraction . Logical functions include <,>,= etc Memory(Register) : which holds the temporary data for specific function.
Control UnitCU Part of the hardware that is in-charge Directs the computer system to execute stored program instructions Communicates with other parts of the hardware
Arithmetic & Logical Units Calculations occur here It knows how to perform operations such as ADD, SUB, LOAD, STORE, . It knows the commands that make up the machine language of the CPU It is the calculator
Registers High-speed Temporary storage Located inside CPU Instruction register Data register Holds instruction currently Holds data waiting to be being executed processed Holds results from processing
How do CPUs work? Control Unit- Manages four basic operations (machine cycle)Fetch- Gets next program instruction from the computer’s memoryDecode- Figure out what the program is telling the computer to doExecute- Perform the requested actionWrite-back (Store)- Write (store) the results to a register or to memory
What’s inside the CPU? Motherboard (mainboard)- Large printed circuit board with thousands of electrical circuits Power supply- Transforms alternating current (AC) from wall outlets to direct current (DC) needed by the computer Cooling fan- Keeps the system unit cool Internal Speaker- Used for beeps when error is encountered Drive bays- Housing for the computer’s hard drive, floppy drive and CD-ROM / DVD-ROM drives