Computer Hardware and Software




In this lesson, you will learn about hardware and software courses 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.

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 Bar-code Reader, Fingerprint, and Robots.

Introduction of Hardware

In the previous post Introduction to Computer, we already have the definition of a computer and its basic 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 output for later use.” 
A computer works with the help of its components. The components of a computer consist of hardware and software. Computer Components and their Functions The computer has main two parts as are under:
  • Hardware 
  • Software


The physical part of the computer that we can see and touch is known as hardware. Computer hardware is the collection of physical elements that constitutes a computer system. Computer hardware refers to the physical parts or components of a computer such as a 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 devices translate data from what humans understand to one that the computer can work with. The 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 

Like a mouse, a keyboard is an input device that allows you to talk to your computer. The keyboard is similar to a typewriter keyboard and is easy to recognize. If your typewriter is older than you, look for components that are covered with keys with letters, numbers, and symbols. If you've used a typewriter, you're probably familiar with many of the keys on your keyboard. In either case, the alphanumerical, symbols, and punctuation keys are self-explanatory. Then check the remaining keys that apply to only one (101 and 104) keyboard.
Other Examples of Input Devices 
Digital Camera: A digital camera lets you take pictures that you can transfer to a computer. Once you have transferred your pictures you can print them, insert them in a word processing document, or send them in an E-mail message.
Scanner: A scanner is like a copier. Scanner instead of making a copy converts the image to digital information and saves it on your computer.
Microphone: If your computer has a sound card (and most computers have one) you can plug in the microphone to digitally record sounds to your computer. 
Joystick: Primarily used in computer games, are levers that move in all directions and typically control specific movements of the computer. 
Light Pen: 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. 
Webcam: 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.

Output Devices

The actual components of the computer that receive input are known as input devices. The CPU process the inputs and response via the output devices. For output, there exist output devices. The outputs below, which are the output devices and what they perform, are described in depth.

  • Monitors
  • Printers
  • Speakers
  • Headphone
  • Projector Multimedia


A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure. The size of a display is usually given as the distance between two opposite screen corners. 

The display screen varies in size from 5 to 30 inches. Output on a monitor is a soft copy, which means it is temporary and available to the end user only until another display is requested. There are some kinds of monitors, which are the following:

  • Monochrome Monitors
  • Color Monitor
  • Flat Panel Monitors
  • Touchscreen Monitors

Monochrome Monitors

A monochrome monitor is a type of computer display that was very common in the early days of computing, from the 1960s through the 1980s, before color monitors became popular. They are still used today in some computerized cash register systems, amongst other select applications.

Unlike color monitors, which display text and graphics in multiple colors monochrome monitors have only one color of phosphor (mono = one, chrome =color). All text and graphics are displayed in that color.

 Color Monitors

A display monitor that is capable of displaying many colors. In contrast, a monochrome monitor can display only two colors one for the background and one for the foreground. Color monitors implement the RGB color model by using three different phosphors that appear red, green, and blue when activated. By placing the phosphors directly next to each other, and activating them with different intensities, color monitors can create an unlimited number of colors. In practice, however, the real number of colors that any monitor can display is controlled by the video adapter.

Flat Panel Monitors

A flat panel monitor can refer to either a computer or television monitor that does not use cathode ray tube (CRT) technology, but commonly LCD or plasma technology. This allows the monitor to have a thin profile, which is how the flat panel monitor gets its name. Because of its lightweight, clarity, and digital technology, the flat panel monitor has become the monitor of choice.

Laptop PCs use space-saving flat panel monitors some less than ½ inches thick. Flat panel monitors use a variety of technologies, the most common being Liquid Crystal Display (LCD) and Thin Filament Technology (TFT). LCD displays are more expensive than passive matrix displays therefore active matrix LCD displays are usually associated with high-end notebook PCs.

Touch Screen Monitors

A touch screen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touch or contact with the display of the device, by a finger or hand. Touch screens can also sense other passive objects, such as a pen. However, if the object sensed is active, as with a light pen, the term touch screen is generally not applicable. The ability to interact physically with what is shown on a display (a form of “direct manipulation”) typically indicates the presence of a touch screen.

The touch screen has two main attributes. First, it enables one to interact with what is displayed directly on the screen, where it is displayed, rather than indirectly with a mouse or touchpad. Secondly, it lets one do so without requiring any intermediate device, again, such as a stylus that needs to be held in the hand, such displays can be attachment computers or, as terminals, to networks. They also play a prominent role in the design of digital appliances such as personal digital assistants (PDAs), satellite navigation devices, mobile phones, and video games.


The printer is also an output device. A printer is a peripheral device used to produce a hard copy of documents stored in electronic form, usually on physical print media such as paper or t4ransparencies. Many printers are primarily used as local peripherals and are attached by a printer cable. In most new printers, a USB cable is used to attach it to the computer. 

There are two broad categories of printers, impact, and non-impact printers. In impact printers printing is achieved by pressing the soled characters against a ribbon, which in turn prints the impression on paper almost like a typewriter. A line of print is achieved by moving a print head across the page. Here are some types of commonly used printers. 

  • Dot Matrix Printers
  • Ink-Jet Printers
  • Laser Printers
  • Plotters

Dot Matrix Printers

A dot matrix printer is an impact printer. It is a type of computer printer with a print head that runs back and forth, or in an up and down motion, on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like the print mechanism on a typewriter. Each dot is produced by a tiny metal rod, also called a “wire” or “pin”, which is driven forward by the power of a tiny electromagnet or solenoid. 

The moving portion of the printer is called the print head. Most dot matrix printers have a single vertical line of dot-making equipment on their print heads, others have a few interleaved rows to improve dot density. Print heads may have 9 to 24 pins. These pins are activated independently to form a dotted character image as the print head moves horizontally across the paper. The quality of the printed output increases with the number of dots in the letter matrix.

Ink-Jet Printers

A type of printer that works by spraying ionized ink on a sheet of paper. Magnetized plates in the ink’s path direct the ink onto the paper in the desired shapes. A typical ink-jet printer provides a resolution of 300 dots per inch, although some newer models offer higher resolutions.

In general, the price of ink-jet printers is lower than that of laser printers. However, they are also considerably slower. Another drawback of ink-jet printers is that they require a special type of ink that does not smudge on inexpensive copier paper.

Because inkjet printers require smaller mechanical parts than laser printers, they are especially popular as portable printers. In addition, color ink-jet printers provide an inexpensive way to print full-color documents.

Laser Printers

A type of printer that utilized a laser beam to produce an image on a drum. The light of the laser alters the electrical charge on the drum wherever it hits. The drum is then rolled through a reservoir of toner, which is picked up by the charged portions of the drum. Finally, the toner is transferred to the paper through a combination of heat and pressure. This is also the way copy machines work. Because an entire page is transmitted to the drum before the toner is applied, laser printers are sometimes called page printers. One of the main characteristics of laser printers is their resolution (how many dots per inch they can print). The available resolutions range from 300 dpi at the low end to 1200 dpi at the high end.


A device that draws pictures on paper based on commands from a computer. Plotters differ from printers. Plotters draw lines using a pen. As a result, they can produce continuous lines, whereas printers can only simulate lines by printing a closely spaced series of dots. 

Multicolor plotters use different colored pens to draw different colors. In general, plotters are considerably more expensive than printers. They are used in engineering applications where precision is mandatory.


Speakers are also part of output devices. These help user to get the audio output. Computer speakers range widely in quality and in price. The computer speakers typically packaged with the computer systems are small plastic boxes. 

Some of the slightly better computer speakers have equalization features such as bass and treble controls, improving their sound quality somewhat.

Projector Multimedia

A video projector takes a video signal and projects the corresponding image on a projection screen using a lens system. All video projectors use a very bright light to project the image, and most modern ones can correct any curves, blurriness, and other inconsistencies through manual settings. 

Video projectors are widely used for conference room presentations, classroom training, home theatre, and live events applications. Projectors are widely used in many schools and other educational institutes, connected to an interactive white hoard to interactively teach pupils.

 Storage Devices

The device used for storage and retrieval of data for later use is called storage devices. These devices keep the data intact even when we turn off our computers. Storage devices are commonly classified into two categories.

  • Primary Storage
  • Secondary Storage

Primary Storage

Primary storage usually refers to a form of semiconductor storage known as random access memory (RAM) and sometimes other forms of fast but temporary storage. To manipulate data within a computer system, we must have a way of storing and retrieving it. Data and instructions are stored temporarily during processing in Random Access Memory (RAM). RAM is also known as Primary Storage.

Secondary Storage

Secondary storage also called auxiliary storage or mass storage bolds data, instructions, and information for future use. Secondary storage (or external memory) differs from primary storage in that it is not a directory accessible by the CPU. The computer usually uses its input/output channels to access secondary storage and transfers the desired data. Secondary storage does not lose the data when the device is powered off. It is nonvolatile.

Here are a few examples of secondary storage devices:

  • Magnetic Disks
  • Compact Disc
  • Magnetic Tape

Magnetics Disks

Magnetic storage used different patterns of magnetization on a magnetically coated surface to store information. Magnetic storage is non-volatile. The information is accessed using one or more read/write heads which may contain one or more recording transducers. A read/write head only covers a part of the surface so that the head or medium or both must be moved relative to another to access data. In early computers, magnetic storage was also used for primary storage in a form of magnetic drums or core memory. In modern computers, magnetic storage takes these forms.

  • Floppy Disk
  • Hard Disk
  • Magnetic Tape

Floppy Disks

A floppy disk is a data storage medium that is composed of a disk of thin, flexible magnetic storage medium enclosed in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive (FDD). The floppy disk was actually invented by IBM for recording maintenance information about its mainframes for the service staff. It was later used by personal computer manufacturers as a convenient way to distribute software for sale. The 31/2 inch diskette comes in two capacities 720 KB and 1.44 MD. The two diskettes are the same size but have different disk densities. Disk density refers to the number of bits that can be stored per unit of area on the disk face surface.

Hard Disk

A hard disk is part of a unit, often called a “disk drive,” “hard drive,” or “hard disk drive,” that stores and provides relatively quick access to large amounts of data on an electromagnetically charged surface or set of surfaces. Today computers typically come with a hard disk that contains several billion bytes (gigabytes) of storage.

A hard disk is really a set of stacked “disks,” each of which, like phonograph records, has data recorded electromagnetically in concentric circles or “tracks” on the disk. A “head” (something like a phonograph arm but in a relatively fixed position) records (writes) or reads the information on the tracks. Two heads, one on each side of a disk, read or write the data as the disk spins. Each read or write operation requires that data be located, which is an operation called a “seek”.

A hard disk or drive unit has a rotation speed varying from 4500 to 7200 RPM. Hard disk manufacturers are working continuously to achieve two objectives, to put more information in less disk space and to enable a more rapid transfer of that information to and from RAM. Generally, the 1 to 5 ¼ inch permanent hard disks have storage capacities from 240 MB to 200 MB.

Magnetic Tape

A magnetically coated strip of plastic on which data can be stored. Tapes for computers are similar to tapes used to store music. Storing data on tapes is considerably cheaper than storing data on disks. Tapes also have large storage capacities ranging from a few hundred kilobytes to several gigabytes. Accessing data on tapes, however, is much slower than accessing data on disks. Tapes are sequential access media, which means that to get to a particular point on the tape, the tape must go through all the preceding points. In contrast, disks are random access media because a disk drive can access any point at random without passing through intervening points.

Because tapes are so slow, they are generally used only for long-term storage and backup. Data to be used regularly is almost always kept on disk. Tapes are also used for transporting large amounts of data.


Short for Compact Disc- Read Only Memory, a type of optical disk capable of storing large amounts of data up to 1GB, although the most common size is 650MB (megabytes). A single CD-ROM has the storage capacity of 700 floppy disks, and enough memory to store about 300,000 text pages.

CD-ROMs are particularly well-suited to information that requires large storage capacity. This includes large software applications that support color, graphics, sound, and especially video.

USB Flash Drive

The flash memory is usually of the format of Erasable Electrical Programmable Memory. In contrast to Random Access Memory, flash memory is also fast. It also retains the data even when ether is a power failure. Flash memory is a non-volatile type of memory. Flash memory has a great demand for its application to store data in mobile phones as well as digital cameras and many other handheld devices. Almost all the devices that are operated using a battery like the mp3 players, PDA, and memory cards of various devices. This flash memory is available in different memory formats with different access speeds.

Flash memory in the coming days will give tough competition to the present types of memory storage devices. The regular storage devices may include optical media like CD-ROM, tape storage devices like floppy drives, etc. even though there are hard drives that use the technology of flash memory devices. They are like pocket hard drives etc. Currently, flash memory chips are being used extensively in digital cameras, USB pen drives, and many other applications.   

Computer Software

All computer programs that we can see or work on are called software.  Set of ordered instructions that enable a computer to carry out a specific task. A program is prepared by first formulating the task and then expressing it in an appropriate programming language. Following are the basic types of software:

  • System Software
  • Application Software
  • Utility Programs

System Software

System software, which consists of programs that control the operations of the computer and its devices, serves as the interface between the user and the computer’s hardware. These programs do not solve specific problems. They are general programs written to assist humans in the use of the computer system by performing tasks such as controlling all operations required to move data into and out of a computer and all the steps in executing an application program. Types of system software are the operating system and language processors etc.

Operating System or Operating Software

An operating system is an integrated set of programs that are used to manage the various resources and overall operations of a computer system, it is designed to support the activities of a computer installation. Its prime objective is to improve the performance and efficiency of a computer system and increase the facility and ease with which as the system can be used. It also makes the computer system user-friendly.  

Every general purposed computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.

Operating systems can be classified as follows:

Multi User: Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.

Multiprocessing: Supports running a program on more than one CPU.

Multitasking: Allows more than one program to run concurrently.

Multithreading: Allows different parts of a single program to run concurrently.

Real-Time: Response to input instantly. General purpose operating systems, such as DOS and UNIX, are not real time.

The operating system provides a software platform on top of which other programs, called application programs, can run. The application programs must be written to run on top of a particular operating system. Your choice of the operating system, therefore, determines to a great extent the applications you can run. For PCs, the most popular operating systems are DOS, OS/2, and Windows, but others are available, such as Linux.

As a user, you normally interact with the operating system through a set of commands. For example, the DOS operating system contains commands some of which are given below:




This command is used to display the list of all directories and subdirectories available.


This command is used to clear the screen.


This command is used to make a directory.


This command is used to change the directory.


This command is used to invoke a text file.


This command is used to copy files from one place to another place. 


This command is used to copy all the files of a folder from one place to another place.


This command is used to display the current date.


This command is used to display the current time.


This command is used to display the version number of DOS.


This command is used to rename a file or directory.

The commands are accepted and executed by a part of the operating system called the commands processor or command line interpreter. Graphical user interfaces allow you to enter commands by pointing and clicking at objects that appear on the screen.

Language Processors

These are the programs used to translate high-level language programs into low-level language programs.


A program that translates source code into object code. The compiler derives its name from the way it works, looking at the entire piece of source code and collecting and reorganizing the instructions. Compilers require some time before an executable program emerges. However, programs produced by compilers run much faster than the same programs executed by an interpreter. Every high-level programming language comes with a compiler. Because compilers translate source code into object code, which is unique for each type of computer, many compilers are available for the same language. For example, there is a FORTRAN compiler for PCs and another for Apple Macintosh computers. In addition, the compiler industry is quite competitive, so there are actually many compilers for each language on each type of computer. More than a dozen companies develop and sell C compilers for the PC.


A program that translates instructions written in a high-level language into low-level language. There are two ways to run programs written in a high-level language. The most common is to compile the program, the other method is to pass the program through an interpreter.

The interpreter will take a long time for the program is long. The interpreter, on the other hand, can immediately execute high-level programs. For this reason, interpreters are sometimes used during the development of a program, when a programmer wants to add small sections at a time and test them quickly. In addition, interpreters are often used in education because they allow students to program interactively.

Both interpreters and compilers are available for most high-level languages. However, BASIC and LISP are specially designed to be executed by an interpreter. In addition, page description languages, such as PostScript, use an interpreter. Every PostScript printer, for example, has a built-in interpreter that executes PostScript instructions. 


This is a type of translator. It also works in the same way as compiler and interpreter work. It is a program, which translates an assembly language program to its machine language equivalent.

Application Software

A program or group of programs designed for end users. Application software consists of programs designed to perform specific tasks for users. Application software sits on top of system software because it is unable to run without the operating system and system utilities.  Popular application software includes word processing software, spreadsheet software, database software, presentation software, and graphics software. Spreadsheet software allows you to calculate numbers arranged in rows and columns and often is used for budgeting, forecasting, and other financial tasks. Database software is used to store data in an organized fashion as well as to retrieve, manipulate and display that data in a meaningful form. Presentation software allows you to create documents called slides that are used in making presentations. These four applications often are sold together as a single unit called a suite in which individual applications are packaged in the same box and sold for a price that is significantly less than buying the applications individually.

Utility Programs

A program that performs a very specific task, is usually related to managing system resources. These are the programs that are used to help the operating systems to smoothly run a system. Operating systems contain a number of utilities for managing disk drives, printers, and other devices.  

Utilities differ from applications mostly in terms of size, complexity, and function. For example, word processors, spreadsheet programs, and database applications are considered applications because they are large programs that perform a variety of functions not directly related to managing computer resources.

Programming Languages

Languages are a communication medium through which we can express our feelings, thoughts, and emotions to others.

The language through which we can communicate with a computer is called computer language. Computer languages are helpful for creating software and program.

Types of computer languages

  • Low-level languages
  • High-level languages
  • Low-level languages

It is a language of 0’s and 1’s. The word “low” refers to a call or nonexistent amount of abstractions between the language and machine language, because of this, low-level languages are sometimes described as being “close to the hardware.” The circuitry of a computer is wired in such a way that it immediately recognized the machine language and converts it into the electrical signals needed to run the computer. The computer can execute programs written in machine language very fast. This is mainly because the CPU directly understands machine instructions and no translation of the program is required.

High-level Language

A programming language such as C, FORTRAN, or Pascal enables a programmer to write programs that are more or less independent of a particular type of computer. Such languages are considered high level because they are closer to human languages and farther from machine languages. In contrast, assembly languages are considered low-level because they are very close to machine languages.

The main advantage of high-level languages over low-level languages is that they are easier to read, write and maintain. Ultimately, programs written in a high-level language must be translated into machine language by a compiler or interpreter.

The first high-level programming languages were designed in the 1950s. Now there are dozens of different languages including Ada, Algol, BASIC, COBOL, C, C++, FORTRAN, LISP, Pascal, and Prolog.

Procedural Languages

Programmers could write a single instruction instead of several cumbersome machine language instructions. These early languages were procedure languages, requiring programmers to solve problems using traditional programming logic. Programmers’ writing in such languages must develop a proper order of actions in order to solve the problem, based on knowledge of data processing and programming. Contrast with non-procedural language.

Object Oriented Languages

A type of programming in which programmers define not only the data type of a data structure but also the types of operations (functions) that can be applied to the data structure. In this way, the data structure becomes an object that includes both data and functions. In addition, programmers can create relationships between one object and another. For example, objects can inherit characteristics from other objects.

One of the principal advantages of object-oriented programming techniques over procedural programming techniques is that they enable programmers to create modules that do not need to be changed when a new type of object is added. A programmer can simply create a new object that inherits many of its features from existing objects. This makes object-oriented programs easier to modify.

To perform object-oriented programming, one needs an object-oriented programming language (OOPL), Java, C++, and Smalltalk are three of the more popular languages, and there are also object-oriented versions of Pascal.

Database Query Languages

These languages are based on a special kind of database called a relational database. Many database management programs in today’s computer world claim to be relational but actually are not. In order for a database management program to truly use Structure Query Languages (SQL), it must follow the relational  


We have created this post for the newbies who are beginners in the computer field. It is designed to develop basic computer skills to enhance your knowledge. Also, you can review our posts on “What is the computer”, “History of Computer”, "Classification of Computers”. If there is any kind of lack in this post or if liked it, please comment to us. Thanks.   


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