Transcript Communicating Information - Home | Comberton Village College

Year 11 Revision Notes
Communicating
Information
Applications
Handling Information
Operating Systems and
Networks
Modelling Spreadsheets
Social Implications
Monitoring and Control
Communicating
Information
INFORMATION TECHNOLOGY
Revision Notes
Audience and Purpose
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All information is communicated for a
purpose, to an audience;
– The audience is the group of people that a
communication is directed at.
– The purpose is the reason the communication
takes place.
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The audience may not always be the same.
The purpose may change.
Emphasis
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A change in purpose may change the
emphasis in presenting the content of a
communication.
The extent to which the audience is likely to
understand what is being communicated
should be taken into account.
Make sure the information is relevant. If
there is too much divergent information the
audience may become confused.
Word Processing
Using a wordprocessor you can:
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write a letter, an essay, a questionnaire, etc;
create, save, open, load and print documents;
move around a document by scrolling
insert, delete and edit text
use different text fonts and sizes, and generate word art
move, cut, copy and paste blocks of text
import and export text, clip art, database and spreadsheet
tables
generate personalized mail using mail merge facility.
Graphics software
Using graphics software you can:
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create, save, open or load and print graphics files
draw on a screen using a variety of colours
use different brushes, sizes and densities of brush strokes
draw freehand and regular shapes
fill shapes with patterns and colours
use different text fonts and sizes
zoom in and out to edit text and graphics
move, cut, copy and paste blocks of text and graphics
import and export scanned images and other graphics
Desk Top Publishing
Using DTP software you can:
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lay out the pages of a newsletter, magazine, etc
create, save, open or load, and print DTP pages
import and export text, scanned images, clipart, database
reports and spreadsheets
resize images
view the page in different magnifications, zoom in and out
move around a page by scrolling up and down it
move, cut, copy and paste blocks of text and graphics
use different text fonts and sizes, and generate word art
Multimedia
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Using multimedia software you can:
– View encyclopaedias that combine text, graphics, sound
etc. on a CD-ROM
– Produce multimedia presentations
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Using e-mail, you can:
– Send and receive messages using the internet
– set up address books and mailing lists
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Using video conferencing, you can:
– see people you are talking to on the screen
– share screens for graphics and other documents
– take part in meetings and debates with people in
different places
Revision Tips
Remember the different ways to generate text
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input using a keyboard
scan form a book using OCR
export from one piece of software and import
copy it from a CD-ROM or the WWW
download it using e-mail
Remember the different ways to generate graphics
– scan line drawings and photos using a scanner
– take photographs using a digital camera
– copy an image from a clip-art library
Handling Information
and Databases
INFORMATION TECHNOLOGY
Revision Notes
Databases
A database is an organised collection of information
consisting of 1 or more files (or tables)
 A database file is a collection of related records.
For example, a file of information about all the
pupils in a school
 A record in a database file is a collection of
related fields. In the records of the same type , the
fields are in the same order.
 A field is an item of information. For example,
each pupils surname.
Fields
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A fieldname (reference) is the name given to a
field. This must be a unique name.
A keyfield uniquely identifies a record. This can
be a record number for instance.
Fields can have different data types. Common
examples are:
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alphanumeric (0-9, A-Z & symbols such as £)
Numeric (integer - whole numbers or real)
Date (in standard format e.g. DDMMYY)
Multiple Choice, Ordered Choice etc
Coded (first 2-3 characters only - usually text)
Data Collection
Data collection can be done using a questionnaire or
other form.
A Questionnaire should
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have a title and introduction explaining its purpose
only collect the information required
be clear and precise about what information is needed
provide sufficient space to write in the information
use character boxes to assist data entry
use tick lists (multiple choice) to show what options are
available
Direct Data Capture
Direct data capture and input can be done
using:
 Optical Mark Recognition (OMR)
e.g.National Lottery or school registers
 Optical Character Recognition (OCR)
 Bar codes
 Magnetic stripe card (e.g. visa or access)
Verification
Verification is checking that the data captured is accurately
input into the computer.
Information input from questionnaires or forms should be
verified
The double entry system involves 2 people inputting the
data. The computer checks that they have both input the
same information. If it is not a mistake has been made
which must be corrected.
Double entry verification ensures accuracy but takes longer
and costs more.
Validation
Validation is checking that the data is reasonable,
for example:
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a length check checks that a field is not too long or too
short;
a type check checks that the information is of the correct
data type;
a range check checks that the information is within the
expected range;
a check digit is recalculated to ensure that, for example, a
bar code has been read accurately by a bar code reader.
Database Integrity
The information on a database has to be kept up-todate and secure. To do this, you:
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edit or amend the information stored in a field if it
changes;
insert or create a new record to add new information to a
file
delete a record to remove it if is no longer needed;
backup the database by making another copy of it;
restore the database from the backup copy if you lose the
original.
What a Database can do
Using a database, you can:
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Keep records of customers, criminals, books, stock, pupils
etc
Select records that match a search condition to find the
information you want.
Sort the information into some order. For example,
descending alphabetical order (Z to A)
Print a report containing the information selected
Export the results of a search into another program
Import text, images etc. from other software.
Teletext
Teletext, e.g. Ceefax, is a simple way of handling
information using a page-based system
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Teletext pages can be received and displayed on a TV or
using a computer.
Pages are broadcast in cycle. You have to wait for your
page to be broadcast.
Teletext is not interactive
Fastext allows several pages next to the selected page to
be stored in memory. Other pages are not accessed any
faster.
The Internet
The Internet is a worldwide collection of interconnected
networks.
There is no one central organisation that owns or
controls the Internet.
It provides services such as electronic mail (e-mail).
To connect at home you need a modem, a telephone line
and an Internet Service Provider (ISP).
An ISP provides dial-in lines so that users can connect to
the Internet. It may also provide other services such
as News and Weather.
The World Wide Web
The World Wide Web runs over the Internet. The
information is stored on information servers (Web
sites, Web servers) located throughout the world.
You can access the web using a browser.
To find information on the web, you could:
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Access a page by typing in its Uniform Resource Locater
(URL). This is its address on the web.
Use a search engine to search for particular topics.
Surf the web by activating hotspots. There are usually
hyperlinks on most pages leading to other pages.
Modelling and
Spreadsheets
INFORMATION TECHNOLOGY
Revision Notes
Spreadsheets
A spreadsheet can be used for a wide variety of
tasks that involve calculations. They are often
used for financial applications and in mathematics.
 A spreadsheet is divided into vertical columns and
horizontal rows,
 Cells can contain different types on information:
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text, e.g. Mr. Jones
numbers, e.g. 23 or £34.67
formulae, e.g. =SUM(A2:A11)
dates and times, e.g. 20/4/99
Cell References
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Cell references can refer to a single cell e.g. D5
A cell reference can be a relative cell reference. This will
adjust automatically when it is moved or copied to a new
position
A cell reference can be an absolute cell reference. This
will not change when it is moved or copied. For example,
suppose C3*$A$1 is in D3 and is moved to D4, the
formula will change to C4*$A$1. $A$1 is an absolute cell
reference, it does not change.
A cell range reference refers to a group of cells. E.g.
B2:D6
What Spreadsheets can do
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Formulae may recalculate automatically when the
numbers in the cells they refer to change.
Cells may be moved or copied from one part of a
spreadsheet to another.
Columns and rows can be deleted and inserted.
Formats can be applied to cells and ranges of cells
It is possible to sort groups of cells
You can generate graphs that illustrate the information
stored in the spreadsheet. For example, bar charts, pie
charts and line graphs.
You can export a range of cells to another piece of
software.
Modelling
A model is a representation of the real world. It is
not the real world. It can be used to:
 improve understanding of a well known situation;
 learn about unfamiliar situations;
 increase awareness and understanding of the
situation modelled;
 help understand problems and try out solutions;
 experiment without danger or expense;
 predict what will happen.
Modelling using a
spreadsheet
Spreadsheets can be used for modelling though they
are more often used to handle information. A
spreadsheet model will:
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allow a range of input variables to be set;
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use formulae to define the rules on which the
model is based;
output information using the variables, stored
values and the rules.
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Common spreadsheet
models
Spreadsheet models commonly used are:
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Price Forecast
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Supermarket queue
Break-even
Predator/Prey
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Monitoring and Control
INFORMATION TECHNOLOGY
Revision Notes
Sensors and Actuators
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A sensor is an input device used to measure
environmental conditions. Different sensors can
monitor temperature, humidity, light, sound,
pressure, wind speed, wind direction, tilt, etc.
An actuator is an output device used to adjust
environmental conditions. Actuators are heaters,
motors, valves, pumps, boilers, etc. Their source
of power could be electricity, hydraulics,
compressed air, etc.
Data logging
Data logging is the automatic recording and storage of the
information provided by sensors. For example, weather
stations automatically record and store the temperature
once every hour.
The stored information can then be downloaded to a
computer perhaps over a network.
The frequency of sampling or time interval gives the time
between measurements.
The period of logging is the length of time the logging takes
place.
Control Systems
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Control systems monitor and control environmental
conditions using sensors to determine what is
happening and actuators to change what is happening
Feedback is a cycle of sensing, processing and
reaction.
Computer control systems use a control interface.
This is the hardware that converts the signals from the
sensors so that the computer can understand them and
the signals from the computer so that the actuators can
understand them.
Computer Programs
Computers themselves are controlled by programs. A
computer program is a list of instructions to a computer
written in a computer language.
 A computer language may be designed to initiate a very
restricted range of actions.
 General purpose computer languages are harder to
understand but can do a wider range of tasks, for example,
BASIC.
 Different program structures can be used in computer
programs. Examples are:
– Conditional statements: IF INPUT = “YES” THEN [action]
ELSE [action]
– A loop is a series of instructions that is to be repeated.
– A procedure is a self-contained sequence of instructions that can
be run from elsewhere in the program.
Flowcharts
Start
No
Switched on?
END
Yes
Measure the
temperature
Yes
Too hot?
Turn off
the heater
No
Yes
Too cold?
No
Turn on
the heater
A flowchart
can be used
to describe
how a task is
done or a
computer
program is
constructed.
Applications
INFORMATION TECHNOLOGY
Revision Notes
Applications
An application is using IT to do a useful task.
IT is used throughout commerce and
industry for a wide variety of applications.
Common commercial applications include: payroll,
stock control, orders and deliveries, banking,
shopping, booking tickets, lottery tickets etc.
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An IT system is the whole system of hardware, software
and human activities that is used in an application.
A legacy system is an old IT system that is still in use.
A manual system is a system that does not use IT.
Processing Information
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Interactive processing takes place when the user and the
computer have a ‘conversation’. It is a cycle of input,
processing, output, and user reaction. Interactive IT
systems react to the information input as they are being
used.
In batch processing, all the data to be processed is
available before processing starts. Data is processed in
batches. For example, a payroll system.
In real time processing, data is processed as it is input.
Real time systems are very fast and interactive. They are
usually run on dedicated computers.
The system life cycle
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System investigation
Feasibility study
System analysis and design
Program design, coding and testing
Implementation
System documentation
Evaluation
Maintenance
– A parallel run tests the new system by running the old system at
the same time.
Operating Systems
and Networks
INFORMATION TECHNOLOGY
Revision Notes
Hardware and Software
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Information Technology is the use of computers and other
equipment to store, process and transmit information.
Hardware is the physical equipment, e.g. monitor.
Software are the programs that control the computer.
Mainframes are large computers
Microcomputers are Personal Computers (PC’s). These
can be desktop PC’s, portables or laptops. Desktops
typically consist of a monitor, a processor case, a hard
disk, a floppy disk drive, a keyboard and a mouse.
Multimedia PC’s also have a CD-ROM drive and stereo
speakers.
Memory and Storage
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Random Access Memory (RAM) is usually installed in
the processor case. Programs and data is stored in RAM
while they are being used. RAM is volatile, the
information stored on it is lost when the computer is
switched off.
Backing storage is on a hard disk, floppy disk or CDROM. Backing storage is non-volatile, it is not lost when
the computer is switched off.
– The size of memory and backing storage is measured in bytes. 1
byte is the memory required to store 1 character.
• 1 Kilobyte (Kb) = 1024 bytes
• 1 Megabyte (Mb) = 1024 Kb
• 1 Gigabyte (Gb) = 1024 Mb
File Operations
Software and data are saved on disk as files. A
directory is a list of all the files on a disk.
File operations are:
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Saving a file.
Loading a file.
Merging two files to form 1 file.
Updating a file by editing or amending it.
Deleting a file by removing it.
Renaming a file.
Copying a file.
Input
Information can be input to a PC using a mouse and
a keyboard. Other input methods are:
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Optical Mark Recognition (OMR) and Optical
Character Recognition (OCR) using a scanner. Bar
codes using a light pen or laser scanner.
Magnetic Ink Character Recognition (MICR), to read
bank cheques. Magnetic Stripe Cards. e.g. Credit cards
Microphone. Voice recognition is spoken input.
Midi technology allows sound and music to be input.
Touch screens using a pen or your finger.
Video digitiser and digital cameras.
Output
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Printers can be:
– Impact dot matrix. Cheap to buy and run, slow with poor quality.
– Ink jet. Cheap to buy but expensive to run. Slow but good
quality.
– Laser. Expensive to buy and run. Quick with excellent quality.
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A printer buffer is RAM memory built into the printer. It
is used to store print jobs, releasing the computer to
continue with other jobs.
Spooling is the queuing of files waiting to be printed on a
hard disk.
Other output methods include:
– Graph plotters, draws using pens. Very high quality.
– Speech synthesis which is the output of human speech.
Operating Systems
An Operating System (OS) is software that runs
between the hardware and the applications
software. An OS will:
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Carry out OS commands. Either through the GUI or at
the command line, e.g. COPY C:\ACCESS\AGENTS A:.
Supervise programs. The OS will try to keep programs
running, giving the user messages when there are
problems.
Make the hardware easier to use, so that you do not have
to know the internal complexities of the hardware.
Continued . . . .
Operating Systems
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Help users decide what to do. For example, if the printer
is unavailable, it will tell you and ask you what you want
to do.
Providing utilities to manage the computer system. For
example, to format floppy disks.
Optimize the use of the computer’s resources. For
example, printing in the background.
Support multitasking, running more than 1 piece of
software at the same time.
Make programs portable, so that they can be run on
different computers with the same OS.
Networks
A network allows users to share software and
hardware, and communicate with other networks.
A Local Area Network (LAN) is a small network,
in one building. Computers are probably
connected by cables.
A Wide Area Network (WAN) is a widespread
network, probably national or international.
Computers are probably connected to a WAN
using a modem and the telephone network.
Network Operating Systems
A Network Operating Systems (NOS) can:
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Allow networked computers to communicate, e.g. e-mail
Support multiaccess, allow more than 1 user to access a
computer at the same time.
Share software and Data. Store data on the server etc.
Share hardware. For example, networked printers.
Manage printer queues and spooling.
Organize user identification and passwords.
Keep a log of who uses the network.
Security
The security of IT systems is important to protect
users’ data and software. To help keep your
system secure you should:
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backup files regularly, using the ancestral system;
limit access using User Identification and Passwords;
use locks, ID cards and guards to control access to room;
put grills and security laminates on the windows of rooms;
attach computers to desks using clamps;
use firewalls to prevent access from external networks;
use automatic virus checks.
Social Implications
INFORMATION TECHNOLOGY
Revision Notes
Lifestyle
Lifestyle and leisure are affected by developments in IT.
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Domestic work has been made easier, this has made it
easier for people to take part in education, employment and
social activities outside the home.
Home entertainment has been enriched by the use of TV,
teletext, PC’s with games and CD-ROM’s, the Internet etc.
Personal communications has been extended through the
use of mobile phones, WWW and e-mail etc.
On-Line shopping and banking are both possible from
home. Users can buy and sell shares, transfer money etc.
Cash-less society: magnetic stripe cards have led to a
dramatic reduction in the use of cash.
Employment
As IT is introduced into the workplace an number of
changes take place.
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Some jobs disappear and some skills are no longer needed.
Some jobs are done in new ways. For example, typists
have been replaced by wordprocessor operators.
New jobs are created. For example, manufacturing
computer hardware and writing software.
New ways of organizing work arise. For example,
teleworking. Teleworking helps the housebound to work,
reduces traffic congestion, and cuts employers’ expenses
by reducing the costs of running a central workplace.
Privacy
IT systems can store large amounts of information.
Personal information may be stored by doctors,
local authorities, schools, the police, banks,
employers etc. These systems can improve the
quality of services but your privacy may suffer.
The Data Protection Act (1984) regulates the use of
personal information. Users of personal
information must register with the Data Protection
registrar, and they must comply with the principles
of good practice.
Freedom
IT can help track individuals which could affect their
freedom of movement and association.
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Entry control systems using stripe cards to regulate
access to many places, buildings and rooms.
Electronic tagging of criminals, used to limit their
freedom
Transport control. IT systems can identify cars that are
speeding and fine their owners automatically.
Closed Circuit Television (CCTV) cameras record much
of what happens in town centres.
Telecommunications by fax, e-mail and telephone can be
automatically monitored.
Implications
IT systems that track individuals’ movements and
monitor their activities have many beneficial uses.
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They help prevent unauthorized access to buildings.
Criminals are constrained and more easily caught.
They can help prevent antisocial behaviour.
However, the same IT systems that can protect
individuals’ freedom of movement and association
could also be used to enforce unreasonable levels
of social control.