In our everything to know about computers series, this is our second post where we will explain what is CPU in a computer. Read the previous post of the series- Everything To Know About Computers: Hardware Introduction.
The full form of CPU is central processing unit. It is the main component of a computer, also known as the brain. CPU performs processing of all the data input by user. The main function of a CPU is fetching and examining data and executing the instructions. In modern or microcomputers, CPUs are built on single chips called Integrated Circuit or IC. The name for this kind of processor is a Microprocessor. Moreover, most of the data processing is done by this microprocessor and the central part of the memory unit to which the peripherals are attached to. So, CPU is the part of computer that interprets and executes the instruction from a program or software.
What is CPU: Parts of a CPU
We can divide the CPU into few different and distinct parts. They are-
1. The Arithmetic Logic Unit or ALU: The arithmetic and logic unit of CPU is responsible for all arithmetic operations. This means addition, subtraction, multiplication and division. The ALU also performs logical operations – as less than, equal to and greater than. In fact, the arithmetic logic unit performs all calculations and comparisons.
2. Control Unit (CU): The control unit controls the data transfer and instructions among the other parts of a computer. Thus we can say that Control Unit of the is the “Central Nervous System” of a computer. It controls and coordinates all the units of the computer. It obtains the instructions from the memory, interprets them and directs the operation of the computer. ALU performs the physical data transfer between memory and the peripheral devices.
Registers:
Basically registers are small high speed circuits that stores data, instructions and memory addresses. Registers have the capacity to store 1 word size of data. 1 word consists of 2 bytes (1 byte = 8 bits.). This is temporary and the word is replaced by a new one when needed by CU. The number and types of registers can vary from one CPU to another. It depends on processors capability. Registers can be categorized as- 1. General Purpose Registers, 2. Pointer Registers, 3. Segment Registers, 4. Index Registers, 5. Flags Register and 6. Instruction Pointer Register. This categorization depends on the functions they perform.
Bus:
In digital form, data is stored as units of eight bits. Bit stands for Binary Digit which can either be 0 or 1. In a register, each of these bits transfer from one register to another through a separate wire. This means there are 8 separate wires for each of the bits. This group of eight wires, that transfer data between registers is known as a bus. So, we can say that, bus is a connection between two registers for transmitting signals between them. There are three major types of Bus. 1. Data Bus, 2. Control Bus and 3. Address Bus. The data bus moves data, address bus moves address or memory location and control bus sends control signals between various components of a computer.
Clock: Clock is another important component of CPU. The CPU clock measures and allocates a fixed time slot for processing each and every micro-operations. SO, CPU allocates one or more clock cycles to complete a micro-operation. CPU executes the instructions in synchronization with the clock pulse.
These are some basic things to know about a CPU. When building a PC, we should pay attention to the CPU. It can determine the power of you PC. It is impossible to built a high end PC without a high end CPU. In our next article of this series, we will write about Input devices. So, please stay with us. Also, thank you for reading and feel free to let us know if we have published any wrong information.
