3-Components of a Computer

A computer is an electronic device that accepts data, performs operations, displays results, and stores the data or results as needed. It is a combination of hardware and software resources that integrate together and provide various functionalities to the user. Hardware is the physical components of a computer like a processor, memory devices, monitor, keyboard, etc., while software is a set of programs or instructions that are required by the hardware resources to function properly. 

Components of a Computer
There are basically three important components of a computer:

  1. Input Unit

  2. Central Processing Unit(CPU)

  3. Output Unit

Input Unit

The input unit consists of input devices that are attached to the computer. These devices take input and convert it into binary language that the computer understands. Some of the common input devices are a keyboard, mouse, joystick, scanner, etc.

  • The Input Unit is formed by attaching one or more input devices to a computer.

  • A user inputs data and instructions through input devices such as a keyboard, mouse, etc.

  • The input unit is used to provide data to the processor for further processing.

Central Processing Unit

The CPU is called the brain of the computer because it is the control center of the computer. It first fetches instructions from memory and then interprets them so as to know what is to be done. If required, data is fetched from memory or input device. Thereafter CPU executes or performs the required computation, and then either stores the output or displays it on the output device. The CPU has three main components, which are responsible for different functions: Arithmetic Logic Unit (ALU), Control Unit (CU), and Memory registers.

  • Arithmetic and Logic Unit (ALU): The ALU, as its name suggests performs mathematical calculations and makes logical decisions. Arithmetic calculations include addition, subtraction, multiplication, and division. Logical decisions involve the comparison of two data items to see which one is larger smaller or equal. 

  • The Arithmetic Logical Unit is the main component of the CPU.

  • It is the fundamental building block of the CPU.

  • The arithmetic and Logical Unit is a digital circuit that is used to perform arithmetic and logical operations.

  • Control Unit: The Control unit coordinates and controls the data flow in and out of the CPU, and also controls all the operations of ALU, memory registers, and also input/output units. It is also responsible for carrying out all the instructions stored in the program. It decodes the fetched instruction, interprets it, and sends control signals to input/output devices until the required operation is done properly by ALU and memory.

  • The Control Unit is a component of the central processing unit of a computer that directs the operation of the processor.

  • It instructs the computer’s memory, arithmetic, and logic unit, and input and output devices on how to respond to the processor’s instructions.

  • In order to execute the instructions, the components of a computer receive signals from the control unit.

  • It is also called the central nervous system or brain of the computer.

Output Unit

The output unit consists of output devices that are attached to the computer. It converts the binary data coming from the CPU to human understandable form. The common output devices are monitors, printers, plotters, etc.

  • The output unit displays or prints the processed data in a user-friendly format.

  • The output unit is formed by attaching the output devices of a computer.

  • The output unit accepts the information from the CPU and displays it in a user-readable form.

What is Hardware?

It refers to the physical and tangible components of the computer system.

Components of the Internal Hardware

1. CPU - The central processing unit (CPU) executes all the instructions and it is considered the brain of the computer system. 

2. Memory  - It stores data and instructions before the execution and the processed data as well.

Types of Memory

A. Internal Memory

  • Random-Access Memory (RAM) – It is a volatile type of memory referred to as Main Memory or Primary Memory.

  • Read-Only Memory (ROM) – contains permanently stored instructions that cannot be changed.

B. External Memory

  • Secondary Memory - Also known as Auxiliary Memory. It is a non-volatile type of memory that is responsible for keeping files permanently.

 

3. Input and Output Unit - It allows communication between the computer and its outside world via input and output devices.

Other parts that go along with the Processor:

Bus - It is an electronic circuit that sends data and messages between the other components.

Ports - They attach input and output devices to the computer.

Expansion slots - It allow the addition of extra features.

Registers  - These are special temporary storage that quickly accepts, stores, and transfers data and instructions for immediate use.

Components of the External Hardware

Input Hardware - it accepts or collects data and converts it into a form suitable for processing.
Keyboard - It is the most commonly used input device.


Terminals - It consists of a keyboard, a video display screen, and a communication line to a mainframe computer.

THREE TYPES OF TERMINAL

  • Dumb – can be used only to input data to and receive information from a computer system.

  • Smart – can do input and output and has some limited processing capability.

  • Intelligent – a fledge microcomputer with a communication link.

POINTING DEVICES

  • Mouse – a pointing device that allows you to control an on-screen cursor.

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  • Trackball – the upside-down version of the mouse. A ball mounted in the box is rolled with the fingers to move the cursor.

  • Joystick – a video display screen that picks up input from the user through the touch of a finger.

  • Light pen –It is a point-and-draw input device that allows you to draw directly on the screen.

  • Digitizing tablet – a pen-like device with which the user “sketches” an image or puck.

  • Pen-based systems – a pen-like stylus to enter handwriting and marks into a computer.

SCANNING DEVICES

Scanning Device - It translates images of text, drawings, photos, and the like into forms of data that can be understood by the computer.

  • Bar code readers – photoelectric scanners that translate the bar code symbols into digital forms

Mark and Character recognition devices

  •  MICR (Magnetic-Ink Character Recognition) – it reads the strange-looking numbers printed at the bottom of bank checks

  • OMR (Optical Mark Recognition) – it reads pencil marks

  • OCR(Optical Character Recognition) – it reads special preprinted characters

  • Fax Machine (Facsimile Transmission Machine) – it scans an image and sends it as an electronic signal over telephone lines

  • Imaging Systems/Image Scanner/ Graphics Scanner – it converts text, drawings, and photographs into forms

  • Smart Cards and Optical cards

  • Smart cards – they contain a microprocessor and a memory chip.

  • Optical Cards – It's a plastic, laser-recordable card used with an optical card reader.

Other Devices

  • Voice Recognition Systems – they convert human speech into digital code.

  • Audio- Input Device – they record or play analog sounds

  • Video- Input Devices – signals that come from a VCR or a camera recorder

  • Electronic cameras – they capture images in electronic form

  • Sensors – they collect specific kinds of data directly from the environment

Storage Hardware. It temporarily or permanently stores data used for processing and the output of such processing.

 Two types:

  • Primary Storage – refers to main memory (RAM).

  • Secondary Storage- refers to storage devices that retain data and instruction in a relatively permanent (non-volatile) form.

  • Diskettes

  • Hard disks

  • Optical storage – use a laser beam to pack information densely on are movable disk

  • Magnetic tapes – sequential file storage represented by various arrangements of magnetized spots along the width of the tape

  • Magnetic disk – a metal plotter where data is represented by magnetized spots on the tracks.

  • Magnetic strip – a recording of a data cell device capable of storing 400 million of data

  • Paper tape – a continuous strip of paper wound on a reel where data is represented by holes punched on the paper.

  • Drum – a recording medium of data represented by magnetized spots that are coated with a magnetically sensitive material divided into tracks.

  • Continuous forms – long sheets of paper where data is represented through printouts.

  • Computer Output Microfilm (COM)- stores large volumes of information printed or photographed as a very small image on sheets or rolls of film called Microfiche.

Output Hardware - It provides a means for the user to view information produced by the computer system.

Two forms:

  • Hardcopy – it is when an information has been recorded in a tangible medium, such as paper or microfilm

  • Softcopy – it is when an output is temporarily displayed on the screen

  • Hardcopy Output Hardware:

  • Printer – it is capable of printing characters, symbols, and graphics.

   Categories: 

  • Impact printer – it has contact with papers like daisy wheel printers, dot-matrix printers, and line printers

  • Non-impact printers –it has no contact with paper like laser printer, ink-jet printers, and thermal printers.

  • Hardcopy Output Hardware:

  • Plotter – they are specialized output devices that can produce high-quality graphics in a variety of colors.

3 types:

  • Pen plotter – the most popular type of plotter

  • Electrostatic plotter – Electrostatic charges create tiny dots on specially treated paper.

  • Thermal plotter – its pins are electronically heated and are used with heat-sensitive paper to produce images.

  • Softcopy Output Hardware:

  • Cathode Ray Tube (CRT) – the most popular softcopy output device used on microcomputers

  • Flat Panel Displays – They are used with portable computers.

System software- facilitating applications programs.

Types of system software

Operating system - refers to a group of related programs that supervise the execution of an application program

  • Operating environment - refers to programs that sit on top of the OS

  • Utilities - a single term for all types of programming aids

  • Programming damages - the programs used to write other programs

  • Language processor - used to convert source program into a form suitable for execution. (Compilers, Assemblers, Interpreters)

Application software - use a program designed to solve problems.

Types of Application Software

  • Package Program - commonly called application package.

  • Custom Program - specifically written for an organization.

Levels of Programming Languages

  1. Machine language

  2. Symbolic language

  3. High-level language

Types of Package Programs

  • word processing software

  • desktop publishing software

  • spreadsheet software

  • database management system

  • graphic software

  • communication software

  • integrated software

  • groupware

  • software suites

  • desktop accessories

  • personal information manager

  • project management software

  • multimedia software

Peopleware - refers to the personnel involved in data processing operations.

Functional Areas of Peopleware:

  • Systems Programming

  • System analysts

  • Application programming

  • Computer Operations

Personnel:

  • Data Entry Operator

  • Computer Operator

  • Computer Programmer

  • System Analysts

  • Computer Center Director