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Parts of computers

There are four main parts which a computer system needs to function effectively and that are critical to system performance. If a part is malfunctioning, it can cause the system to stop operating, it can cause program errors or it can slow down the performance of other devices. Understanding how these parts and devices interact within the system can optimize hardware and software performance.

  1. Motherboard

The motherboard is a printed circuit board which uses “bus” architecture to map out critical system components and provides connectors for devices such as, the power supply, memory, hard drive, input/output slots and the central processing unit (CPU). If you examine a motherboard, it looks like a street map. The lines on the motherboard are physical addresses to a device which carries instructions to the central processing unit which is the brain or scheduler of the computer system.

  1. Central Processing Unit (CPU)

The central processing unit (CPU) or brain of the computer system processes complex functions in the system. The CPU chip receives instructions from the system board and software applications. Today’s CPUs can process data measured in milliseconds. The CPU also has a co-math processor built into the chip to handle mathematical functions. For example, when a spreadsheet program, such as Microsoft Excel calculates formulas, the program is accessing the co-math processor function of the CPU.

  1. Hard Drive

A hard drive stores programs, data and information. The most important attribute of the hard drive is the boot sector record which reads information from the disk to “boot up” the operating system for a person to use software applications. Modern hard drives have RAM memory chips sets built in to help send a program application to the CPU.

  1. RAM/ROM Memory

Random Access Memory (RAM) is an integrated computer chip used to access any memory location or address on the motherboard directly. The RAM chips are made up of millions of circuits and capacitors. RAM is active when the computer is turned on and while the computer is on, it helps allocate memory to system operations, especially the CPU while releasing other devices and processes which are not actively using RAM resources. Random Access Memory (ROM) can only be read from the system and primarily holds the instructions for the performance of low-level system devices. Without instructions located in ROM, a user would not be able to power up a computer.


A microcomputer is a computer with a central processing unit (CPU) as a microprocessor. Designed for individual use, a microcomputer is smaller than a mainframe or a minicomputer.

The term microcomputer is not as commonly used as it was during the 1970s-1980s. We now refer to microcomputers as, simply, computers, or personal computers (PC). A microcomputer’s CPU includes random access memory (RAM), read-only memory (ROM) memory, input/output (I/O) ports, interconnecting wires and a motherboard.

In 1970, Hewlett-Packard (HP) manufactured and released a microcomputer as a calculator with varying levels of programmability, although the Datapoint 2200 by Computer Terminal Corporation (CTC) is credited as the first microcomputer. Intel’s x86 processor family can also be traced back to CTC’s release.

A personal computer is a microcomputer. Technically, a microcomputer is a computer in which the CPU (central processing unit, the brains of the computer) is contained on one single chip, a microprocessor. Most workstations are also considered microcomputers, for the same reason, although some personal computers are as fast as the fastest workstation. And a computer used by more than one person (a multi-user computer) is still a microcomputer as long as it has a microprocessor for its CPU.


CPU chips or central processing unit chips are used in digital computers and are the semiconductor component where most calculations take place.

Specifications include:

  1. Clock speed
  2. Internal register size
  3. Data input/output (I/O) bus width
  4. Memory address bus width
  5. Maximum memory

Today, there are two main manufacturers of CPU chips: Intel and Advanced Micro Devices (AMD). Customers can buy computer chips from these companies directly, or through their networks of distributors.

A typical CPU has a number of components. The first is the arithmetic logic unit (ALU), which performs simple arithmetic and logical operations. Second is the control unit (CU), which manages the various components of the computer. It reads and interprets instructions from memory and transforms them into a series of signals to activate other parts of the computer. The control unit calls upon the arithmetic logic unit to perform the necessary calculations. Third is the cache, which serves as high-speed memory where instructions can be copied to and retrieved. Early CPUs consisted of many separate components, but since the 1970s, they have been constructed as a single integrated unit called a microprocessor. As such, a CPU is a specific type of microprocessor. The individual components of a CPU have become so integrated that you can’t even recognize them from the outside. This CPU is about two inches by two inches in size.

CPUs are located on the motherboard. Motherboards have a socket for this, which is specific for a certain type of processor. A CPU gets very hot and therefore needs its own cooling system in the form of a heat sink and/or fan.

The ALU is where the calculations occur, but how do these calculations actually get carried out? To a computer, the world consists of zeros and ones. Inside a processor, we can store zeros and ones using transistors. These are microscopic switches that control the flow of electricity depending on whether the switch is on or off. So the transistor contains binary information: a one if a current passes through and a zero if a current does not pass through.

Transistors are located on a very thin slice of silicon. A single silicon chip can contain thousands of transistors. A single CPU contains a large number of chips. Combined, these only cover about a square inch or so. In a modern CPU, however, that square inch can hold several hundred million transistors – the very latest high-end CPUs have over one billion! Calculations are performed by signals turning on or off different combinations of transistors. And more transistors means more calculations.

Early CPUs were quite bulky and did not contain as many transistors as they do today. Chip manufacturers, such as Intel and AMD, have invested a lot of research into making everything smaller and fitting more transistors inside a single processor. So when there is a new generation of chips, it typically means they have come up with a smarter way to pack more processing power into a single CPU.

The general name of the processor, such as Intel Pentium 4, Intel i7, AMD Athlon, and AMD 870, refers to the underlying architecture of the CPU. There are so many different ones that it can be hard to figure out what you really need in a new computer. The best way is to go with the latest processor type that falls within your budget.

Clock speed is one measure of computer “power,” but it is not always directly proportional to the performance level. If you double the speed of the clock, leaving all other hardware unchanged, you will not necessarily double the processing speed. The type of microprocessor, the bus architecture, and the nature of the instruction set all make a difference. In some applications, the amount of random access memory (RAM) is important, too.

Some processors execute only one instruction per clock pulse. More advanced processors can perform more than one instruction per clock pulse. The latter type of processor will work faster at a given clock speed than the former type. Similarly, a computer with a 32-bit bus will work faster at a given clock speed than a computer with a 16-bit bus. For these reasons, there is no simplistic, universal relation among clock speed, “bus speed,” and millions of instructions per second (MIPS).

Excessive clock speed can be detrimental to the operation of a computer. As the clock speed in a computer rises without upgrades in any of the other components, a point will be reached beyond which a further increase in frequency will render the processor unstable. Some computer users deliberately increase the clock speed, hoping this alone will result in a proportional improvement in performance, and are disappointed when things don’t work out that way.

A multi-core processor is an integrated circuit (IC) to which two or more processors have been attached for enhanced performance, reduced power consumption, and more efficient simultaneous processing of multiple tasks (see parallel processing). A dual core set-up is somewhat comparable to having multiple, separate processors installed in the same computer, but because the two processors are actually plugged into the same socket, the connection between them is faster.

Ideally, a dual core processor is nearly twice as powerful as a single core processor. In practice, performance gains are said to be about fifty percent: a dual core processor is likely to be about one-and-a-half times as powerful as a single core processor. Multi-core processing is a growing industry trend as single-core processors rapidly reach the physical limits of possible complexity and speed. Most current systems are multi-core. Systems with a large number of processor core — tens or hundreds — are sometimes referred to as many-core or massively multi-core systems.

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