THE COMPUTER

 

Concept of a computer.

1. A computer is an electronic device that processes user’s input (data) to a desired output (information).

2. A computer is an electronic device that is capable of accepting data, processes data and then generates output (information).

3. A computer is an electronic device that manipulates data to give out meaningful information.

4. A computer is an electronic device that uses instructions (programs) to accept and process data given to it in a variety of forms in order to produce useful information.

5. A computer is an electronic device that accepts, processes, stores and outputs data at high speed.

A computer is said to be an electronic device because it utilizes electrical signals to process data.

Significance of computer.

Computer is very important in our daily life as it is applied in various areas.

Areas where computers are used.

1. Supermarkets

Most retail stores use computer to help in the management of daily activities like stock control.

2. Offices

Most modern offices functions have been automated for faster information distribution and document processing. Therefore computer have increased efficiency in offices by reducing the time and effort needed to access and receive information.

3. Banks

Computers have increased efficiency in banking services by ensuring better record keeping and document processing.

Also special cash dispensing machines called Automated Teller Machines (ATM’s) have enabled automation of cash deposits and withdrawal services.

4. Industries

Computer are used to monitor and control industrial processes. There is a wide use of remote controlled devices called robots. A robot is a machine that works like human being but performs tasks that are too unpleasant, dangerous or complex and tedious to assign to human being.

5. Hospitals

Computer are used to keep patient’s records in order to provide easy access to a patient’s treatment and diagnosis history.

Computerized medical devices are used to get a cross sectional view of the patient’s body that enables physicians to get proper diagnosis of the affected body parts with high levels of accuracy.

Computers are also used to control life support machines in Intensive Care Unit (ICU).

6. Transport

Computers are used to monitor vehicle traffic in busy towns, in aircraft navigation and in making reservations.

7. Communication

Integration of computers and telecommunication facilities has made message transmission and reception to very fast and efficient. The world is said to have become a Global Village due to the speed of transmitting information around the world using computers.

8. Law enforcement agencies.

Information stored in computers such as fingerprints, images and other identification details help law enforcers carry out criminal investigations.

9. Education

Computers are widely used in teaching and learning processes. Experiments in subjects like Chemistry or Physics may be demonstrated using a special computer program that can depict them on the screen through a process called simulation.

Learning and teaching using computers is referred to as Computer Aided Learning (CAL) and Computer Aided Instruction (CAI)

10. Domestic and entertainment.

Computer are used at home for recreational activities such as watching movies, playing music and computer games. They can also be used in storing in personal information, calculating and keeping home budgets.

11. Library services

In a computerized library, a computer enables library personnel to easily access and keep updated records of books and other library materials. Library users can also use computers to search for titles instead of using the manual card catalogue.

Computer System

A computer system is a collection of three entities namely hardware, software and liveware that work together to receive, process, manage and present information in a meaningful format.

Hardware

Hardware refers to physical or tangible components that make up a computer system. Computer hardware is classified into four categories:-

• Input devices

• Central Processing Unit (CPU)

• Output devices

• Storage devices

Input Devices

Input devices are devices used to enter data into a computer. They convert user input which is in human readable form to machine language that a computer can process. These devices can be classified according to the methods that they use to enter data, namely:-

1. Keying devices

2. Pointing devices

3. Scanning devices

4. Other technologies used to capture data

1. Keying devices

Keying devices are devices used to enter data into a computer through typing method. These devices convert typed numbers, letters and special characters into machine readable form before processing takes place.

Types of keying devices

1. Traditional keyboard

Traditional keyboard is the most common type of keying device. It is full sized rigid keyboard.

2. Flexible keyboard

A flexible keyboard is a more portable keyboard that can be folded and packet into a bag.

3. Ergonomic keyboard.

An ergonomic keyboard is a type of keyboard specially designed to provide comfort and alleviate wrist strain.

4. Keypad

A keypad is a miniature keyboard used on portable devices such as Personal Digital Assistant (PDA), laptop and mobile phone.

5. Braille keyboard

Braille keyboard is a keyboard designed for use by the blind. It consists of keys identified by raised dots.

2. Pointing devices

Pointing devices are devices used for controlling a pointer cursor on the screen

Types of pointing devices

1. Mouse

A mouse is the most common pointing device. There are three types of mouse. These are/;-

Standard mouse

The standard or traditional mouse has a ball underneath, two buttons and an optional scroll button located between the left and the right buttons

Optical mouse

An optical mouse works by using a tiny digital camera to take 1,500 pictures every second of the surface on which it is resting. Interpreting the pictures indicates the direction of the mouse movement hence the pointer’s position on the screen

Cordless mouse

Cordless or wireless mouse is a battery powered mouse that uses radio or infrared waves instead of being physically connected to the system unit.

2. Trackball

A trackball works just like a mouse, only that its ball is located at the top. Instead of moving the device on a flat surface, the user rotates the ball using a finger. Some computer keyboards come with an integrated trackball, hence no need for a mouse.

3. Joystick

A joystick is an input device that looks like lever used to control a pointer on the screen. It is purposely used for playing computer games.

4. Light pen.

A light pen operates by detecting the command or item being illuminated by it.

5. A stylus

A stylus is used on devices such as PDAs that recognize commands or hand written data.

3. Scanning devices

Scanning means capturing data from an object and converting it into digital format. Scanning devices can be classified according to technology used to capture data. These are:

1. Optical scanners

Optical scanners capture data using optical or light technology. Some examples of optical scanners include:-

Optical Mark Recognition (OMR) scanners

OMR scanners detects marks made on a piece of paper using ink or soft pencil, by passing an infrared beam over them. OMR are used to mark multiple choice

questions, analyzing responses to structured questionnaires and selecting correct number combinations from lottery tickets.

Optical Bar Recognition (OBR) scanners

OBR scanners are used to capture data coded as lines of varying thickness known as barcodes or Universal Product Code (UPC). Barcodes hold manufacturer’s details and the product code but not prices details because prices vary from one place to another.

Optical Character Recognition (OCR) scanners

OCR scanners are used to read typewritten, computer printed, or handwritten characters and transform the image into a soft copy that can be manipulated using a word processor. A more advanced OCR scanner called flat-bed is used to capture pictures and real objects.

2. Magnetic scanners

Magnetic scanners are used to capture data written using magnetic ink or coded onto a magnetic strip. Common examples of magnetic scanners are Magnetic Ink Character Recognition (MICR) and card readers.

Magnetic Ink Character Recognition (MICR) scanner

MICR scanners are used to read characters written using magnetic ink. An example of MICR is the cheque reader used in banks.

3. Digitizers

A digitizer also known as graphic tablet allows a user to draw an image using a stylus. The image drawn does not appear on the tablet but on the computer screen. A digitizer is used for tracing highly detailed engineering and architectural drawings and designs.

4. Digital cameras

A digital camera captures image and stores the image in digital form. Pictures are mostly stored on a memory card instead of a film. The stored image can be edited, printed or uploaded to the internet.

4. Other input technologies

1. Touch screen

Touch screen technology let the user to touch the screen using a finger or stylus in order to write or select an item. A touch screen is mostly used in retail stores, airports, on smartphones and PDAs

2. Voice input.

Voice input is an input technology, where a microphone is used to enter data in form of speech into a computer.

3. Interactive whiteboard.

An interactive whiteboard also known as a smartboard is a large interactive display that connects to a computer. The computer display is projected onto the board’s surface where users control the computer and write using a pen or a finger. Smartboards are used in places such as classrooms, corporate board rooms, seminars and broadcasting studios.

THE CENTRAL PROCESSING UNIT (CPU)

The Central Processing Unit (CPU) is also known as the Processor is the most important component of the computer. It is regarded as the brain of the computer because all processing activities are carried out inside the processor. In microcomputer the CPU is housed inside the system unit. It is mounted on a circuit board known as the motherboard or the system board. The CPU consists of three functional elements namely:-

1. Control Unit (CU)

2. Arithmetic and Logic Unit (ALU)

3. Main memory.

Control Unit (CU)

Control Unit coordinates all processing activities in the CPU as well as input, storage and output operations. The Control Unit Uses a System Clock to coordinate those activities. The system clock sends electrical signals as its means of communication. The number of pulses per second determines the speed of a microprocessor. The faster the clock pulses, the faster the CPU, hence the faster the computer can process data.

Arithmetic and Logic Unit (ALU)

ALU is an element of the CPU where all arithmetic and logical operations are carried out. These basic arithmetic operations includes, addition, subtraction, multiplication and divisions. Logic operations are based on the computer’s capacity to compare two or more values. In order for the ALU to be able to process data, it has a special temporary storage locations called registers, which hold the data just before processing. It also holds the results after processing.

Main Memory

Main memory is also known as primary storage. It is a type of storage that is directly accessible by the processor. Computer memory can be classified into two forms, Read Only Memory (ROM) and Random Access Memory (RAM)

Read Only Memory (ROM)

This type of memory is used to store programmed instructions and data permanently or semi- permanently. Information is usually written into ROM during its manufacture. This information remains unchanged for long periods of time, for example, special purpose computers, and computerized fuel pumps instructions etc.

Types of ROM

ROM can be categorized depending on the permanence of instruction or data written on it, thus there are four types of ROM.

1. Mask Read Only Memory (MROM)

In this type of ROM once the content is written on it by manufacturer, it cannot be changed.

2. Programmable Read Only Memory (PROM)

This ROM allows a user to change (alter) only once after the content is written on it.

3. Erasable Programmable Read Only Memory (EPROM)

This type of ROM has transparent quartz window through which its content can be erased by exposing it to Ultra Violet (UV) light.

4. Electrically Erasable Programmable Read Only Memory (EEPROM)

This is the type of ROM which can be erased and programmed using electricity. An example of EEPROM is the memory that stores the Basic Input/output System (BIOS)

Characteristics of ROM

1. The content can be read only but not written.

2. It is non-volatile. This means its content is not lost when the computer is switched off.

3. It stores permanent or semi-permanent instructions from the manufacturer called firmware.

Random Access Memory (RAM)

It is also known as working storage, used to hold instructions and data needed by the currently running applications. The information in RAM is continually read, changed and removed by the processor.

Also the content in RAM is held temporarily and its content is lost once the computer is turned off. Because of this, RAM is often referred to as temporary memory. Therefore before switching off the computer, it is important that one stores (saves) his/her work in a device that offers relatively permanent storage facility.

Types of RAM

1. Static RAM (SRAM)

2. Dynamic RAM (DRAM)

Characteristics of RAM

1. The content can be read and written in it

2. It is volatile. This means that its content lost once the computer is switched off.

3. It is user defined since the user dictates what is to be contained in the RAM

Size of RAM

There are various sizes of RAM. In early days a small CPU had a RAM of 4 kilobytes, meaning that it could hold a maximum of approximately 4,000 characters at any time. However, today, a relatively small CPU can accommodate RAM of 64 megabytes (MB), meaning that it can store up to approximately 64 million characters.

In most modern computers the size of RAM can be increased by plugging more memory chips in DDR memory slots found on the motherboard.

Memory capacities

Memory and storage capacity is measured in special units called bytes. A byte is equal to a single character. Characters can be a number from 0 to 9, letters A to Z or a special symbol. For example a number like 3457 has four bytes while the words, My Home have seven bytes since the space between them has 1 byte.

Memory quantities can be expressed in:

8 bits	=	1 byte (B)
1024 bytes	=	1 kilobyte (KB)
1024 kilobytes	=	1 megabyte (MB)
1024 megabytes	=	1 gigabyte (GB)
1024 gigabytes	=	1 terabyte (TB)

Types of Processors

Processors can be classified into two categories depending on the number of instruction set.

1. Complex Instruction Set Computer (CISC)

2. Reduced Instruction Set Computer (RISC)

Complex Instruction Set Computer (CISC)

CISC processor is made up of a large number of complex instructions set. This design is widely used on Pentium processors made by Intel Cooperation. Other manufacturers such as AMD and Cyrix also use the same technology. Some examples of CISC processors are Intel Pentium and PDP-II processor.

Reduced Instruction Set Computers (RISC)

RISC processor uses fewer instructions set. The main manufacturers of RISC processors include Motorola and Sun Microsystems Companies. Motorola used to produce PowerPC RISC processor used on Apple computers while Sun Microsystems produces SPARC used on servers.

Trends in processors technology and speed

Over time, manufacturers of microprocessors such as Intel, Advanced Micro Devices (AMD), Cyrix and Sun Microsystems have several brands of microprocessors in the market.

Processor performance is measured in clock speed which is expressed in Hertz (Hz). A hertz is a unit of frequency which measures the number of cycles per second in a signal. A processor clock speed can be in kilohertz (kHz), megahertz (MHz) and Gigahertz (GHz).

OUTPUT DEVICES

Output devices are peripheral devices that a computer uses to give out information produced after the processing operations.

Types of Output Devices

1. Soft copy output devices

2. Hard copy output devices

SOFT COPY OUTPUT DEVICES

These are output devices that produce intangible output that can be seen or heard such as screen display and sound. Examples of such devices include monitors, LCD projectors and speakers.

Monitors

A monitor is also known as Visual Display Unit (VDU) or the screen. It is used to display information in the form of text, pictures and video.

There are three common types of monitors namely CRT, LCD and GPD.

1. Cathode Ray Tube (CRT) monitors

CRT monitor consists of a long glass tube with an electron gun on one end and the screen on the other. The electron gun shoots electrons to illuminate the screen. The screen is coated with tiny phosphorus dots consisting of three primary colours namely red, green and blue.

2. Liquid Crystal Display (LCD) monitors

LCD monitor is made up of special liquid crystals. The LCD monitor is not as bulky as CRT monitor; it consumes less power and has little strain effect on eyes. LCD monitors are made up of two technologies namely Passive Matrix and Active Matrix.

In Passive Matrix, LCDs create images by scanning the entire screen. This type of screen requires little power but have poor clarity.

Active Matrix displays are made using Thin Film Transistor (TFT) technology. These displays consume more energy but offer better clarity.

3. Gas Plasma Display (GPD)

GPD resembles LCDs only that they use gas instead of liquid crystals. They contain millions of pixels that are illuminated by charged neon gas. This technology is mainly used to produce High Definition TVs (HDTV) and wall display screens.

Common screen features

Pixel

Stands for picture elements which are tiny dots used to form images displayed on the screen. Pixel has the three primary colours namely red, green and blue

Colour depth

Colour depth refers to number of colours which can be displayed by a pixel. The colour depth is measured in bits.

Resolution

This is the total number of pixels in one square inch usually given in dots per inch (dpi) or bits. Mathematically is expressed as the product of horizontal pixels and vertical pixels (for example 640 x 480 = 307, 200 pixels). The higher the resolution, the more number of pixels per square inch, hence clearer the images.

The resolution of a screen is affected by the size of the screen as shown in the following table

Screen Size (in inches)	Preferred Resolutions
14”	640 x 480
15”	640 x 480; 800 x 600
17”	800 x 600; 1024 x 768
21”	800 x 600; 1024 x 768; 1280 x 1024

Refresh rate

Refresh rate refers to the number of cycles (times) a monitor’s image is replaced or repainted on the screen every second. Most monitors have refresh rates of between 60 and 80 cycles per second. This is expressed in Hertz (Hz) with 1 Hz being one cycle per second. The higher the refresh rate, the clearer the picture will be on the screen

Dot Pitch

Dot pitch refers to the distance between one pixel and another on the screen. When the pixels are closer to each other the sharper the image whereas when the pixels are further apart the grainer the image. The dot pitches of most monitors are between 0.25 mm and 0.28 mm.

Display size/size of the screen

Display size refers to diagonal length of the screen measured from top right to bottom left corner of the glass surface.

Controls of a monitor

Monitor controls refers to a set of switches and knobs that are used to adjust the image displayed on the screen. These controls can either be physical controls or On Screen Display (OSD) controls.

1. Physical controls

1. Power switch – Used to switch the power to the monitor ON or OFF.

2. Power Indicator – A small LED which is lit when the monitor’s power is switched ON.

3. Contrast control – Used to adjust the contrast of an image. One can reveal details in light and dark areas to suit the taste of the operator.

4. Brightness control – Used to adjust the brightness of the picture on the screen. The picture can be darker or brighter as preferred by the operator

5. Horizontal control – Used to adjust the horizontal position of an image on the screen

6. Vertical control – Used to adjust the vertical position of an image on the screen

2. OSD controls

By Using OSD controls, a user is able to control many more features of the screen and sound than when using physical controls.

Video Graphic Adapters

For a monitor to display information, it must be connected through a video port to a video adapter which is plugged or integrated on the motherboard. A video adapter determines the resolution and clarity of the monitor. Examples of video adapters include

1. Colour Graphics Adapter (CGA) – The oldest type that displays text and images up to 16 colours

2. Enhanced Graphics Adapter (EGA) – An improvement of CGA, also displays in 16 colours

3. Video Graphic Array (VGA) – Displays text, graphics and videos using 256 colours

4. Super Video Graphics Array (SVGA) – Displays text and graphics using more than 16 million colours, has a minimum resolution of 800 x 600 pixels.

5. Extended Graphics Array (XGA) – Has a resolution of up to 1024 x 768 pixels. It is popular with 17 and 19 inch monitors.

6. Super Extended Graphics Array (SXGA) – Has a resolution of 1280 x 1024 pixels and is popular with 19 and 21 inch monitors.

7. Ultra-Extended Graphics Array (UXGA) – is the latest and highest standard.

Sound Output Devices

These are output devices that produce sounds such as beeps, audio or digital. Some computers come with inbuilt speakers; hence there is no need to connect external ones. An external speaker should be connected to a sound card through the jacks on the system unit or on multimedia monitor.

The Digital Projector

A digital projector is connected to a computer by cable and used for projecting information appearing on a computer screen onto a vertical screen or wall.

The digital projector is a popular tool for making presentation to large groups of participants in classrooms, lecture theatres, workshops and seminars particularly to display data already stored on the computer.

HARD COPY OUTPUT DEVICES

Hard copy refers to tangible output that can be felt such as a paper. Hard copy output devices include printers, plotters and facsimile (fax)

Printers

Printers are output devices used to produce information on a piece of paper. They are classified according to different printing mechanism. The two categories are Impact and Non-Impact Printers

Impact Printers

Impact printers print using striking mechanism. This means that they strike the paper in order to form an imprint on it. Examples of impact printers include Dot Matrix and Daisywheel printers.

1. Dot Matrix printers

A dot matrix printer has a set of pins on the printers head which strike on an ink ribbon placed over the paper.

2. Daisy wheel printers

A daisy wheel printer has a removable flower-like wheel consisting of spokes with embossed characters. When printing, the wheel is rotated to align the required character and then the character are hit with a hammer

Impact printers are cheaper to run and print for long periods without breaking but they produce low quality printouts.

Non-impact Printers

Non-impact printers print using ink, thermal or laser mechanisms. They are faster and more quiet than the impact printers. There are types of non-impact printers. These are inkjet, thermal, laser and photo printers.

1. Inkjet printers

Inkjet printers print by spraying tiny ink droplets onto a paper to create an image. A colour inkjet printer may have black and tricolor cartridges that contains cyan (a greenish-blue colour), magenta (reddish-purple) and yellow (CMY) compartments.

Inkjet printers are cheaper to buy and produce quality printouts but they are more expensive to run due to the high cost of replacing the cartridges

2. Thermal printers

Thermal printers use thermal technology to heat ink which is normally in wax or resin form to melting point before fusing it onto the paper. They are mostly used in point of sale terminals to print receipts and bar codes

Thermal printers produce high quality printouts but they are more expensive to purchase and run.

3. Laser printers

Laser printers print by shining a laser beam to create an image on a rotating drum. As the beam hits the drum, it ionizes some regions which attract ink toner particles. The toner is then fused onto a piece of paper through heating.

Laser printers print very fast compared to inkjet and thermal printers. They are cheaper to run and produce high quality printouts. However they are expensive to purchase.

4. Photo printer

Photo printers are special purpose printers designed to print photos.

Factors to consider when purchase a printer.

1. Print quality

Dot matrix printers are good for bulk printing of draft documents Laser printers are good for printing official documents

Thermal printers are good for checkout counter receipts

2. Initial cost

Laser and thermal printers are more expensive than inkjet printers.

3. Running cost

The cost of maintaining inkjet printer is higher than that of maintaining laser printers

4. Speed

The speed of a printer is measured in pages per minute.

5. Colour printing

Colour printers especially lasers are relatively more expensive

Plotters

A plotter is a large type of hard copy output device. Plotters are mostly used for printing geographical, architectural and engineering drawings such as maps, advertisement posters to be placed on billboards, machine parts etc.

SECONDARY STORAGE DEVICES AND MEDIA

Secondary storage (auxiliary storage/permanent storage/non-volatile storage), are devices that provide alternative long-term storage for programs, data and information. Secondary storage devices can be classified according to:-

1. Removable as removable and fixed

2. Technology used to store and retrieve data as magnetic, optical, magneto-optical and solid state.

REMOVABLE STORAGE MEDIA

Removable storage media are those that are not housed inside the computer. Data is read and written into the media using a device known as drive.

Magnetic Tapes

Magnetic tape is a thin belt made using a thin ribbon of mylar coated with a thin layer of magnetic material composed of iron oxide. The tape may be housed inside a plastic cartridge. Data is read from or written using a tape drive. Examples of magnetic tapes include reel-to-reel tapes, cassette tapes and cartridge tapes.

Disadvantages of magnetic tapes

1. Magnetic tapes are slow because of the linear storage of data records on the tape

2. There is space between successive data records called Inter-Record Gap (IRG) which results in wastage of storage space
   

Floppy disks

A floppy disk (diskette) is made up of a small flexible round disk coated with magnetisable iron oxide. To read or write contents into floppy disk, a computer must have a floppy drive. Floppy disks are of different sizes with different capacities. Common sizes include 5.25 inch and 3.5 inch.

Zip disks

A zip disk is a high capacity magnetic diskette that resembles a floppy disk. When compared to a

3.5 floppy disk, a zip disk has a higher storage capacity and is physically thicker a zip disk can hold as much as 250 MB. Zip disks mostly come with separate portable external zip drives

Jaz disks

Jaz disks resemble zip disks only that they can hold as much as 2 GB. Data is read or written using internal or external jaz drives.

High Capacity Floppy

High capacity floppy disks simply known as HiFD disks are high capacity diskettes that can store up to 200 MB of data. HiFD drive can also read the magnetic 1.44 MB diskette

Laser Servo 120 Super Disks

Laser servo 120 SuperDisks technology (LS-120) is a diskette that resembles the 3.5 inch diskette but uses optical technology. It has a greater storage capacity and speed of data retrieval (up to 240 MB). The LS-120 drive can read and write both the 3.5 inch floppy disk and the 120 MB super disk.

Care of magnetic storage media

In order to avoid accidental loss of data or information held on magnetic media, the following rules must be observed

1. Do not expose a magnetic media to strong magnetic fields

2. Do not expose a magnetic media to excessive heat

3. Do not drop magnetic media on the ground because the impact weakens magnetism

4. Do not bend or fold a magnetic media or put heavy weights on them to avoid breaking or damaging it.

5. Do not touch the magnetic surfaces

6. Do not remove a media from the drive when it is still being accessed by the computer because this may result to data loss.

Optical Storage Media

These are storage media which the data is read and written from them using a laser beam. A laser beam is a very strong concentrated light.

Advantages of Optical Storage Media

1. They store very large volumes of data

2. Data stored in them is more stable and more permanent than the magnetic media.
   

Compact Disks (CD)

Compact Disks hold large quantities of data and information. One disk can hold as much as 700 MB. They are mostly used to store data and information that require a lot of space such as video clips, software, sounds etc.

Compact disks are available in three forms namely:

1. Compact Disk – Read Only Memory (CD-ROM)

CD-ROM contains data that can only be read but cannot be written on. The surface of CD- ROM is made into pits and lands (bumps)

2. Compact Disk – Recordable (CD-R)

CD-R is coated with special dye which changes colour to represent data when burned using a laser beam. Once data is burned on a CD-R, it becomes read only.

CD-ROM and CD-R are referred to as Write Once Read Many (WORM). Data is only recorded once but can be read as many times as possible.

3. Compact Disk – Rewritable (CD-RW)

CD-RW allows the user to record, erase and rewrite new information just as one would with floppy disks.

Digital Versatile Disk/Digital Video Disk (DVD)

These disks resemble compact disks in every aspect. The only difference is that they have a higher storage capacity of up to 17GB. They are suitable for recording motion pictures such as videos because they offer better sound and picture quality than CDs.

Optical Card

An optical card resembles an MICR card but data is read and written optically on a stripe. These cards are mostly used in banking and other business organizations to record customer details.

Optical tape

It is similar to a magnetic tape only that data is stored on it by using optical technology.

Solid State Storage Media

Solid state storage is a non-volatile storage that employs integrated circuits that mechanical, magnetic, or optical technology. Some examples of solid state devices are memory sticks and flash pen drives

FIXED STORAGE MEDIA

Hard disks (Hard Drives) are good examples of fixed storage media. The hard disk is mounted inside the computer. It is made up of metallic disk platters together with a read/write head, housed in a protective metal case.

Most computer hard disks are connected to the motherboard via a channel called controller. Some of these controllers are Integrated Drive Electronic (IDE), Enhanced IDE and AT Attachment (ATA).

Hard disks are very popular storage media as they provide efficient data transfer and large storage capacity.