Types of Computers Supercomputers Mainframe Personal Computer Laptops Embedded Computers PDA.

ICT Hardware

Class: Ayomi HasencleverYear: 9NL

Types of Computers

SupercomputersMainframePersonal ComputerLaptopsEmbedded ComputersPDA

Super Computers Supercomputer can be as big as a generator Fastest and most expensive (100 million pounds +) Very few organizations can afford one Large universities and weather stations have supercomputers to carry lots of

data and research Pharmaceutical companies use supercomputers for drug research Supercomputers are used mostly for research SC generate a lot of heat, which means they need to be housed in cool rooms

and the air in the room has to be very clean VERY expensive and sensitive Use a lot of cables Need their own backup electricity power to ensure they work if there is a power

failure Use a lot of power and electricity

Mainframe Computers Large powerful computers that carry out many different tasks for different people Slower than supercomputers and less expensive Can execute billions of instructions per second Can process large amounts of data simultaneously Usually connected to lots of terminals, printers, disk drives, etc. Big schools may use mainframe computers for student information Airlines for bookings, tickets, cancelations Police for storing data about crimes committed everyday Banks use mainframe to manage thousands of customer accounts each day Utility companies (Gas, Water, Electricity, Service Charge) use mainframe to

calculate customer bills Must be operated by specialist and experts Must be kept in an air conditioned room when in use Kept away from floor because they want to stop currents from entering the floor

Personal Computers In the past they were called micro computers Now they are called PC’s or Desktops Desktop PC consists of a monitor, tower unit, keyboard, and a mouse Modern PC’ s are powerful, they can carry out millions of calculations per

second

Uses Of PC’s:

• Office Applications (Word Processors, Spreadsheets)• Creating and playing music• Making and editing movies• Taking pictures• Accessing the internet for research or leisure• CAD (Computer Aided Design)

Laptops Are more expensive in comparison to PC’s When they first came out they were very expensive but for the high demand

for them they reduced in price People’s work patterns and living patterns make most people have laptops People use laptops to carry on working whilst they are traveling from one

place to another Becoming an essential in people’s everyday lives Modern laptops use wireless networking, which makes it easy for people to

move around with them When laptops first came out the batteries didn’t last long, but now they last

for longer periods of time Early laptops were large, bulky, and heavy to carry around Laptops designs have improved causing them to become compact and light

to carry

PDA (Personal Digital Assistant)

Originally designed as a digital organizer People have developed the PDA further to make it

more like a computer Can send emails, play games, use word processors Similar to Palm Tops, except palm tops that have a

keyboard

Embedded Computer Is a single chip that contains all the elements that are essential for any computer

Essential Elements For A Computer:• RAM (Random Access Memory)• ROM (Read Only Memory)• CPU (Central Processing Unit)• Input Device• Output Device• Clock• Power Supply

Can also be called a Micro Controller Main purpose of an embedded computer is to control something Televisions, camera’s, washing machines, microwaves, phones have embedded

computers

Manual devices

Keyboard There are many different types of Keyboards The Keyboard is made up of buttons called keys e.g. letter symbols, function keys, command keys.

Advantages of keyboards: Types in data quickly Very little training is needed Specialist keyboards are available such as an ergonomic

Disadvantages of keyboards: Easy to make mistakes Not suitable for creating diagrams Disable people often find keyboards difficult to use Using a keyboard for a long time it might lead to RSI

Mouse Also called pointing device Most common input device The mouse has 2 buttons and a central wheel Works by tractable movement

Advantages for mouse: Is supplied with a desktop Requires very little training Works well with the keyboard

Disadvantes for a mouse: Needs a flat surface If the tracker ball gets dirty it will stop working Using the mouse too often can lead to RSI

Touchpad Is found on a laptop computer It can be used as a mouse It works by dragging your finger over it It reacts to slide heat You can control it with your finger

Advantages of a touchpad: Useful for laptops The positions of the touchpad is fixed Very short finger movements are required

Disadvantages of a touchpad: Moist and sweaty fingers can disrupt the signals picked up by the sensors Gloves cant be worn Takes practice and skills to control the position of the curser

Joystick Allows you to tell the computer which direction to make the

pointer move on the screen Many games are controlled by joystick Pilots use joysticks for controlling an aircraft

Advantages of a joystick: Gives a better gaming experience

Disadvantages of a joystick: It can break easily More difficult to control than a mouse

Scanner Can be used to convert images or text on paper into a digital format that can be used on the computer Works by shining a light beam onto the surface of the object that you are scanning The light is then reflected back onto a sensor that detects the color of the light,

this is then used to build a digital image Optical Character Recognition (OCR) can be used to convert text on paper into

text which can be edited on a word processor So people that want to make a copy of something (Picture, Certificate) you would

scan the picture and it will scan it on the computer Three types of scanner: Flat Bed and Handheld and Biometric The most popular is the flat bed Handheld scanners or used commercially (Shops, Stores, Checkout tills) Biometric is used to scan things of the body (Thumbs, Eyes, Etc.) Normally used for security

Digital Camera Records images electronically on a memory card , rather than on a film The images can be downloaded from the memory card onto the computer You can change them with photo editing soft wear Most digital cameras let you view the pictures before you print them The quality of the image depends on the resolution or the number of megapixels Two types of graphic images: Bit Mapped Images and Vector Based Images Many digital cameras can take video clips along with sound

Advantages of a Digital Camera:• Don’t need film• Images can be view immediately and deleted immediately• Images can be edited and formatted• Extra memory or memory sticks can be used to store images• Images can be incorporated onto websites or documents

Disadvantages of a Digital Camera:• Can be expensive• When the memory is full the images must be downloaded or deleted

Graphics Tablet Often used by graphic designers and illustrators Using a stylus pen to draw on a screen More natural and accurate drawings can be made Consists of a flat pad and stylus pen

Advantages of a Graphic Tablet:• Much more natural to draw with• Drawings can be more accurate

Disadvantage of a Graphic Tablet:• Not used for selecting or clicking on menu items

Microphone

Can be used to input soundThe sound is detected by the microphone and

an electrical signal is sent to the computer

Concept Keyboard

Is a flat board that contains a grid of buttons The program for each button is programmed to do a particular task People that work in fast food restaurant use these kind of keyboards Used when fast input is needed Useful for people who find a normal keyboard difficult Also factories use concept keyboards Its much faster The keyboard is waterproof Very poor for text Its limit to the option shown in the keyboard

Automatic Input Devices

Magnetic Ink Character Reader (MICR)

The soft wear it uses is called Magnetic Ink Character Recognition Find this on credit cards (Black stripe on back of credit cards) MICR reads magnetic stripes and magnetic ink The stripe contains information about account holder The cards is put into a reader and reads the information The reader can read the ink on data on passports You need special soft wear for the computer to read what has been inputted and

its called MICRS (Magnetic Ink Character Recognition Software) Chip and Pin are used in bank cards Its very expensive

Optical Mark Readers (OMR)

Used to detect marks made in pencil on preprinted documents

Its expensive Sometimes they use them in exams Its quick, easy, and accurate but sometimes if the document is damaged it can’t be read properlyFast method of imputing a large amount of data

Sensors Devices that input data from the physical environment

Two Types: Measure things that human beings can detect, and sensors that detect things humans can’t

Main sensor types are:

• Temperature• Light • Magnetism• Touch• Radar• Microwave• Sound

Optical character recognition

Software that goes with scannersConverts it into digital data Its cheaper than paying someone to type the text Its faster if someone text itIt can also re-create tables You need very good quality OCR software to be

able to read the text accurately

Output devices

Monitors They come in different shapes, sizes and forms The picture on a monitor is made up of very tiny dots, called pixels. The higher numbers of pixels the better the output Larger monitors make working on the computer easier on the eye, but its more expensive

2 types of monitors:• Cathode Ray tuned monitors• TFT monitor

TFT monitors are quieter, but it can damage easier than CRT monitors.

Sometimes they are noisy They produce a lot of heat The quality of a TFT screen isn't that clear as a CRT monitor

Printers We use printers to hard copy our work Types of printers: • Lasers printer• Ink Jet Printer Many people use them, because they are quiet, print quickly and

produce high quality prints There a black and white printers, they are much cheaper than color

printers. The cost for page is low Very expensive The toner is very expensive Expensive to repair They are very heavy

Ink Jet Printer They are very cheap to buy The ink isn't expensive The ink is wet Many homes use them More compact, you can easily carry it around Cheaper to replace Nosier than laser printer Color printing is sometimes slow Cost for print out per page is more expensive You need to replace the toner more often The toner can dry out when you don’t use the printer The color is not the same, when you print out the paper

Dot Matrix printer

Very noisy They are cheap to buy They are very strongThey are used in dirty places e.g. factoriesThe print quality is poorThey are very slowThey cant print out color print out

Plotter Plotter can draw high quality images Engineers use them Map makers use them Architects use them It uses a pen to draw Print out large images They are slower than all the other printers Each line is drawn separately More expensive than any other printers Not very good at printing text

Types of Plotter:• Flat bed plotters • Drum plotters • Pinch roller

Computer memory

Bits and bytes Data can be stored and measured in bytes One bytes can contains 8 bytes A bits can only be 0 or 1 A series of 0 and 1 is known as a binary code Every key character has a binary code Computers only understand binary code

e.g. the word BAG will occupy 3 byte memory each storage location contains data such as a number, a character or a

string of characters, computer instruction, part of a picture or another address of data

One thousand and twenty four bytes make up a kilo bits

Types of memory

ROM (Read Only Memory) Its permant, which means it doesn’t change or erase Its know as a “Non Volatile Memory”, because it doesn’t disappear after

switching your computer off ROM are not device or physical things

RAM (Random Access Memory) Its different because its temporary Only works when the computer is switched on Its know as a “Volatile Memory” Nothing is stored permant on RAM

They both store data inside the computer

Data storage

Internal Backing Store

Hard disk are the main Internal Backing Store Hard disks have large storage capacityAre found inside the computer

Floppy disk drive

Are not common anymoreIt can be easily stored Its not recommended Is a magnetic device

CD-ROM and CD- Write

CD-ROM (Compact Disk Read Only Memory)You can store data once, you cant add You can burn music and movies on to itThey are optical devices Memory capacity 700 MG Make sure you buy the right format

Types of CD’s: CD write or also known as CDW

Flash drive They are small and light They are portable, removable and re-writable They use a USB port on the computer to transmit or receive

data They are more fashionable looking Easy to transmit viruses if you put it near a metal all your data will be erases You can easily lose your Flash Drive Its more expensive than CDs and DVDs It’s a optical device

DVD DVD- Digital Versatile disk Very similar to CD’s The memory contains more space You can store on one side and on the other side Make sure you buy the right format Produces a better quality of sound and image Are now very cheap A DVD player can read CDs and DVDs, but a CD player cant read a DVD There are many DVD formats Also they can be easily damaged Is a optical devices Types of DVD’s: DVD minus R DVD plus R DVD minus W DVD plus W

DVD-R and DVD + R DVD-R can be played on most home DVD player DVD-R media is at the moment the cheapest most common Can only be used in DVD Recorders and Burners that support

DVD-R recording or multi-format recording Its rewriteable Has a 4.7gb DVD disc The DVD+R disc type does not compare well with DVD-R as far as

DVD playback compatibility They can only be used in DVD Recorders and Burners that

support DVD+R

Magnetic tape

It’s a magnetic deviceIt can store large amount if dataUsed to backup dataLarge organizations use itIt uses serial access to data Needs a special type of equipment to read or record

data Over 100 GB memory capacityIts cheaper to store data on them