Computer Hardware and Software

Computer Hardware and Software


In this lesson, you will learn about hardware and software course in depth. Physically a computer is a combination of different hardware devices such as a System Unit/CPU, Monitor, Keyboard, Mouse, Printer, etc. And you will also understand software basics and its types, the operating system, its basic functions, utility programs, device drivers, and different types of application software.

Computer Components and their Functions

The computer has main two components as are under:

  • Hardware
  • Software

Introduction of Hardware

In the previous post Introduction to Computer, we have already the definition of a computer and its basics components, we will review them here again.

“A computer is an electronic machine which solved our problems”


“A computer is an electronic machine which processes raw data (input) into meaningful information (output) and also stores for output for later use”.

 A computer works with the help of its components. The components of a computer consist of hardware and software.

Computer Hardware Parts

Hardware Basics of a Computer

Physically a computer is a combination of different hardware devices such as a System Unit/CPU, Monitor, Keyboard, Mouse, Printer, etc. You will learn about the system unit and its internal components such as Motherboard, Processor, RAM, ROM, Expansion Cards, Expansion Slots, etc. You will also learn briefly about cutting-edge technologies such as Barcode Reader, Fingerprint, and Robots.

Central Processing Unit (CPU)

System Unit

Inside the computer case, which is hidden between all the cables and the gizmo, is a particularly important part of the computer known as the central processing unit (or CPU for short). The CPU is also known as a computer chip or a microprocessor (or processor for short). Some say that the CPU is the brain of a computer, while others call it the heart. The CPU does all the work. Calculate, process, and keep doing everything. You can think of it as a talented stage manager. When it works well behind the scenes, you don’t notice it. You are just enjoying the performance.
Originally, CPUs had very original names like chips. OK, it may not be. The name was actually based on a number like 8088. The next few names in the series (286, then 386, and 486) were actually abbreviations for 80286, 80386, and 80486. The 586 at that time was called the Pentium. After that, the names became pretty strange: Pentium Pro and Pentium MMX. Eventually, the name returned to the Pentium 2, Pentium 3, and Pentium 4 semi-ordered numbering system, “despite a mixture of Roman and Arabic numerals.” This is for now. Both the Pentium 3 and the Pentium 4 are still quite common.
Intel makes most CPUs. In fact, Intel is the company that came up with the name Pentium. However, AMD and VIA Technologies are two other well-known CPU manufacturers. Their CPUs are less expensive and use a different naming system (such as the AMD Athlon and the AMD Duron). Intel actually makes a less expensive version of the Pentium as well, which it calls the Celeron. Celeron works like a Pentium, but it’s not that fast. 

By the way, speed is all about the CPU, and each subsequent version of the CPU will gradually get faster. CPU speed is measured in megahertz (MHz). For newer models, it will be measured in gigahertz (GHz). Megahertz is equivalent to millions of cycles per second. One gigahertz is equivalent to billions of cycles per second. The higher the number, the faster the speed. You may see 3.06 GHz Intel Pentium 4, 1.40 GHz Pentium III, and 2.20 GHz Celeron. Another common measure of the CPU is the number of bits it can process at one time. Bits are the smallest amount of information that a computer can process. Eight bits make up one byte, and one byte corresponds to one character. 8-bit or 16-bit computer. Currently, they can be up to 32 and 64 at a time.


Type of CPUs

Sr.# Speed Description
1 1 GHz to 3 GHz Intel Pentium 4 Processor The Pentium 4 is Intel’s more recent and fastest generation of CPUs, with processing speeds over 3 GHz.
2 450 MHz to 1 GHz Intel Pentium III Processor Launched in 1999, Pentium 3 CPUs are still found in some new computers.
3 1.06 to 2 GHz Intel Celeron Processor Intel’s Celeron CPU is an inexpensive processor designed for people on budget. Celeron processors are very similar to Pentium processors, but they have less built-in memory.
4 500 MHz to 3 GHz Intel Xeon Processor Don’t expect to see any Xeon-based computers at your local computer store—it’s designed for high-end servers.
5 850 MHz to 1.67 GHz AMD Athon Processor The Athlon processor is equivalent to Pentium processors—only it’s less expensive.
6 1.5 GHz to 1.8 GHz AMD Sempron Processor The Sempron CPU is AMD’s answer to Intel’s Celeron processor. It has less built-in memory and is designed for people on a budget.

We tell you now that some older processors with their release date and speed.

Older Processors

Sr.# Processors Release Date Speed
1 8088 1979 8MHZ
2 286 1982 12.5 MHZ
3 386 1985 25 MHZ
4 486 1989 66 MHZ
5 Pentium 1993 133 MHZ
6 Pentium II 1997 266 MHZ

Each CPU has a set of pins through which all its communication takes place with the other devices.  Some pins are used to carry the output signals from the CPU and others accept signals from the outside world. CPU consists of three units named ALU (Arithmetic and Logic Unit), CU (Control Unit), and MU (Memory Unit). CPU is located on the motherboard. 

ALU (Arithmetic and Logic Unit)

It is the part of the CPU all types of data are processed. All Arithmetic and logical operations are performed in arithmetic and logic units. Arithmetic operations such as addition, subtraction, multiplication, division, and logical operations such as less than, greater than, and equality are performed in the ALU. Apart from the numeric data, alphabetic data can also be compared according to an assigned sequence. When data is transferred using input devices to the primary storage, it will be there in the primary storage until it is needed in the ALU where processing takes place. No processing occurs in primary storage. Intermediate results generated in the aLU are temporarily transferred back to the primary storage until needed at a later time. Data may thus move from primary storage to ALU and back again to storage many times before the processing is finished. Once complete, the final results are released to an output storage section and from there to an output device. The engineering design of ALU determines the type and number of operations that it can perform. 

To perform arithmetic and logic operations many hardware components are used like encoder-decoder, binary adder-subtractor, multiplexer, and de-multiplexer. AND, OR, NOT gates, etc. These components are combined to form ALU, 

CU (Control Unit)

It is important compnents of CPU. It acts as a supervisor of the computer. By selecting, inerpreting and seeing to the execution of program instrtuctions the control unit of the CPU maintains order and directs the operation of the entire system. It provides the clock pulses that are used to control and manage the system. Although the control unit doesn’t process data, it acts as a central nervous system for the other data manipulating components of the computer. 

A the beginning of processing the first program instruction is selected and fed into the control unit from the program storage area., There it is interpreted, and then from there, signals are sent to other components to execute the necessary action. Further program instructions are selected and executed one after another until the processing is complete. 

CU (Control Unit)

CPU has its own memory to store data. Instructions are also stored in this memory. This memory area is called MU (Memory Unit) or CPU registers. These are the fastest storage area in a computer. Few most commonly used registers of a CPU and AX, BX, CX, and DC. These registers are available in different sizes like 16, 32, and 64 bits. 

Memory can be classified into two types. 

  • RAM (Random Access Memory) 
  • ROM (Read Only Memory)

RAM (Random Access Memory) 


It is also called Random Access Memory. It is a type of main or primary memory. It is temporary storage area to hold the data and instructions that the Centrial Processing Unit (CPU) needs. Each program is loaded into memory to run, This allows the CPU direct access to the program. DRAM, SRAM & MRAM are its three types. 


The features of RAM are:

  • It is volatile 
  • It is costly 
  • It is temporary in nature 
  • It has unique addresses to store data
  • It stores data in the form of 0’s and 1’s 
  • It is available in a larger size
  • It is available in different sizes and speeds 
  • It is easier to replace in a computer

ROM (Read Only Memory) 


ROM stands for Read-Only Memory, computer memory on which data has been prerecorded. Once data has been written onto a ROM chip, it cannot be removed and can only be read. 

Unlike main memory RAM, ROM retains its contents even when the computer is turned off. ROM is referred to as being nonvolatile, whereas RAM is volatile. Most personal computers contain a small amount of ROM that stores critical programs such as the program that boots the computer. In addition, ROMs are used extensively in calculators and peripheral devices such as laser printers, whose fonts are often stored in ROMs. PROM, EPROM & EEPROM are its three types.


The features of ROM are:

  • It is non-volatile 
  • It is cheaper than RAM
  • It is static and will retain its contents. 
  • It is more reliable than RAM as its circuit is simple
  • It is available in larger sizes than RAM
  • It is not easy to replace in a computer

Computer hardware refers to the physical parts or components of a computer such as the monitor, mouse, keyboard, computer data storage, hard drive disk (HDD), system unit (graphic cards, sound cards, memory, motherboard and chips), etc. all of which are physical objects that can be touched. These include the input and output devices as well as the system unit.

  • Input Devices
  • Output Devices
  • Storage Devices
  • Communication Devices

Input Devices

The input device is any peripheral (a piece of computer hardware equipment to provide data and control signals to an information processing system such as a computer or other information appliance. Input device Translate data from what humans understand to one that the computer can work with. Most common are keyboard and mouse.



Without a way to communicate with the computer, the computer would be useless. You need an input device for this. Basically, you can use an input device to communicate with your computer. Two examples of input devices are the keyboard and Mouse. We’ll talk more about keyboards later. Let’s focus on the mouse first.

That funny-searching item that, frankly, looks as if a mouse (with its oval frame and lengthy tail-like wire connecting it to the computer) is the mouse. Originally, computer systems most effective got here with a keyboard. But in 1968 Doug Engelbart invented the mouse. In 1984, Apple Computers added the mouse to its Macintosh computer systems. Shortly thereafter, the mouse was the preferred device on all computer systems.

The mouse acts as a hand-held pointing tool that permits you to manipulate the moves of that blinking object on your display screen referred to as a cursor. Depending on the software program you’re the use of and the project you’re doing, the cursor can also additionally resemble such symbols as a slanted arrow, an “I”, or a vertical line. A cursor is basically a vicinity-marker that looks on your computer display screen. You flow the mouse to the vicinity of the cursor over an item in your display screen and click on the mouse buttons to pick out that item.

The preferred mouse has buttons and a rollerball on the underside, which moves the cursor at the display screen whilst you flow the mouse. A rollerball mouse works excellent whilst used on a mouse pad, particularly one which has a tough texture on its surface. Some mousepads now include a wrist relaxation to assist customers to hold their fingers and wrists in higher alignment.



The keyboard is any peripheral (a piece of computer hardware equipment to provide data and control signals to an information processing system such as a computer or other information appliance. Keyboard translates data from what humans understand to one that the computer can work with. Most common are keyboard and mouse.

Other Example of Input Devices

Sr.# Input Devices Description
1 A digital camera lets you take pictures that you can transfer to a computer. Once you’ve transferred your pictures you can print them, insert them in a word processing document, or send them in an e-mail message
2 A scanner is input device that like a copier. Scanner instead of making a copy, convert the image to digital information and save it on your computer.
3 If your computer has a sound card (and most computers have one) you can plug in a microphone to digitally record sounds to your computer.
4 A light pen is an input device that uses a photosensitive detector to select objects on the display screen. A light pen is similar to a mouse, except that you can use the light pen to move the pointer and point the pen directly at the object to select an object on the display screen.
5 A webcam is a video camera used in conjunction with a computer and its function is to stream audio and video of another person through a computer network internet. The webcam is built-in into the laptop computer. You can also make video calls from the webcam via the internet.

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