What is Central Processing Unit?
The central processing unit, or processor or microprocessor, as some call it, is the nerve center of the system. It performs central control functions. All the computational, logical, and operations decisions are made here. It contains the logic circuitry for performing the various computational activities. It controls the operation of all the functional units. It fetches machine instruction from memory, decodes these instructions and ensures that the operations called for by the instructions are executed correctly. In order to do all this, it communicated or interfaces with the input and output units and the memory.
CPU is responsible for all events inside the computer; IT controls all internal and external devices, performs arithmetic and logic operations. The instruction set is “hard-wired” in the CPU and determines the machine language for the CPU. The more complicated the instruction set is, the slower the CPU works. Processors differ from one another by the instruction set. If the same program can run two different computer brands they are said to be compatible. Program written for IBM compatible computers will not run on Apple computers because these two architectures are not compatible.
Central Processing Unit has 3 component parts:
- Control Unit
The type of operations that the CPU can do include:
(a) Retrieving data from memory
(b) Outputting data to memory or ports
(c) Storing the data temporarily and retrieving it as and when required.
(d) Converting data of one form into another.
(e) Manipulating alphabetic or alphanumeric data like word processing, letter writing, shorting in alphabetic or alphanumeric orders, editing, making catalogs, etc.
(f) Math operations i.e. making arithmetic calculations like addition subtraction, multiplication, division, and exponentiation etc.
(g) Making logical decisions like comparing two values to find out which one is greater with the help of logical operations such as AND, OR, NOT
(h) Communicating data to far off distances.
(i) Program control operations such as jump to a new spot, skip the next instruction, and “if..then..” statements
(j) Response to special external impulses (“interrupts”).
Basically, the CPU does everything in binary language i.e. with the help of 0 and 1.
A CPU doesn’t have to run a whole computer. These are specialized CPU made that are explicitly geared to do specific tasks, such as runt the electronics in a car, or a VCR, or microwave oven. In fact, inside the computer itself are a number of these “embedded” CPUs that run the keyboard, the video controller, the serial ports, the network card, and the disk controller.
The two main features of the CPU are
- Its speed measured in millions of instructions per second;;
- The word size.