Computers and Information

8/11/2019 Computers and Information

1/26

Computer Fundamentals

Computers and Information


2/26

Getting Started

Before you can login as explained in the GettingStarted handout, the computer must be booted

up which happens when we turn on the powerWe usually have to use the power switch on themonitor and the main box of the computerwhich goes by many names:

CPU, Tower, case, or simply the computer Best described as the System Unit


3/26

What devices have be plugged into

power outlet?System UnitMonitor

PrinterSpeakersScanner

External HD/Optical DriveCamera (outlet or battery)DSL/Cable/Network devices

With so manydevices, we runout of wall outlets

and need moreOutlet expandershave more plugsSurge protectors

have additionalparts to protectthe electroniccomponents


4/26

An Aside

Surge Protectors try to prevent voltagespikes from messing up your computerThe most important thing to protect is thePHONE LINE as surges easily come in on itLighting strikes commonly destroy dialupmodems and DSL routers (and sometimesthe whole computer)


5/26

All components need a DATA

connection to the computer A Data connection lets signals carryingdata to go to and from the main box

Some devices get power from thecomputer over the data connection:

Mouse, keyboard, microphone, and USBdrives

Other devices have their own power cordPrinter, monitor, scanner, external Hard Drive


6/26

Types of Devices

All components have a particular role toplay in the computer systemThis is based on how the device relates tothe data you want to work withThe types are:

Input, Output, Processing, Storage


7/26

Types of Devices

Input from real world to computerOutput from computer to real worldProcessing manipulates data thathas been entered into the computer

Storage hold information that hasbeen entered into or created by thecomputer


8/26

Input

Accepts data from real world and gets itinto the computerMouseKeyboardScannerMicrophone


9/26

Output

Takes data that is in computer and gets itout to use in the real worldMonitor/LCD projectorPrinterSpeakers


10/26

Processing

Manipulates data stored in the computerto create something new

CG effects in movies or checkbook balanceThis happens in the System Unit wherethe CPU (Central Processing Unit) chip and

motherboard are located


11/26

Storage

Holds information that has been enteredinto the computer or created by doing

processing on what was enteredInformation is held in FILES on disk drives

FloppyUSB drive (not a disk but acts like one)HardCD/DVD (optical)


12/26

Work

Steps in using Computer:Boot upLoginWork (can be work or play to us)

Shutdown (can hit power switch if all datafiles already closed)


13/26

What Work do we do with

Computer?DocumentsNumbers (checkbook, spreadsheets)

Lists (address book, calendar)MusicPictures

VideoGamesEmail/IM/Chat

Search/Shop on World Wide Web


14/26

Information

All the computer work we do is tied toInformationThe computer can store three types:

Auditory music, speech, sounds Visual pictures, graphs, videoLanguage/Numbers documents, emails,chat, web pages, etc.


15/26


16/26

How do we go from Information to

Numbers?We have to measure the information andassign a number to the measurementThis can be the level of a sound wave at apoint in time or the color/brightness of aspot in a picture

Language/Numbers are easy just assigna number to each character


17/26

Encoding a Sound Wave


18/26

Simple Wave


19/26

Sampling = Convert to Numbers

These numbers encode thesound


20/26

Numbers = Digital The numbers 7-8-9-5-3-4-0-3-6-4 represent the sound We have Digitized the sound wave By putting them on the graph and connecting the dots

we can recreate the wave

But Not very accurately in this case!

Small number of samples and levels cantrepresent sound well.


21/26

More samples and More Numbers

(levels) = Better sound

2 4

2 6

2 8

2 9

3 0

3 1

3 2

3 3

3 5

3 7

4 0

4 1

4 0

3 0

2 8

2 6

2 4

2 2

1 8

1 6

1 7

1 9

2 1

2 1

1 9

1 4

6 3

0

0

1

1 9

2 1

2 1

2 4

2 9

2 8

2 6

2 4

2 2

Better sampling represents sound well butcreates a lot more numbers to store!


22/26

Pictures

Similar to sounds but numbers areassigned to different colors (rather than

the height of the wave)Picture is broken down into many smallpieces with a color assigned to each piece

Pieces are called Pixels


23/26

Digitized Pictures

Pixel


24/26

Numbers to ColorThese numbersencode the firstcolumn of pixels.

Every other pixel inthe picture is alsorepresented by anumber

This means LOTS ofnumbers!

40394142

4249504942393935342033343534


25/26

Characters are Bytes

In computerese the letters of thealphabet, the ten digits and all thedifferent symbols like ]-*%#$... (inshort all the characters we use) arecalled Bytes

Each byte is paired to a number inthe computerThe word computer would take 8

bytes (numbers) to store


26/26

Summary So FarMost of the things humans do areinformation basedComputers are so popular because theyhelp us work with Information (its anInformation Tool)The only thing the computer can store is

numbersInformation must be transformed intonumbers so we can use the computer to

work with it