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AQA AS Level ICT - INFO 2

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by

Thomas Storey

on 9 June 2014

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Transcript of AQA AS Level ICT - INFO 2

Health and Safety in the workplace is enforced by the legislation
'Health & Safety in the Work Act' of 1974
, which states that employers have a duty to minimise the amount of risk to employees in the workplace
The
'Display Screen Equipment (VDU) Regulations' of 1992
also regulates the use of computer equipment.

A workplace should have an appointed
Health and Safety Executive
, who has the responsibility of promoting Health and Safety in the workplace.

To minimise risk to employees, employers can provide:
Ergonomic devices
such as keyboards and mouses to prevent the development of RSI.
Appropriate training
to ensure employees know the regulations, and can use their ergonomic devices.
Spacious work stations
and
large desks
capable of seating the computer and other paperwork, with a matte surface to reduce glare.
Chairs
that are comfortable, and adjustable to prevent back and neck ache.
Computer screens
that are glare free, tiltable and have adjustable brightness settings.
Eye tests
and glasses for those who need them, along with
regular breaks
.
Unit 1 - An ICT System and its Components
Unit 2 - Data and Information Cont.
AQA AS Level ICT - INFO 2
By Thomas Storey
Unit 2 - Data and Information
Unit 3 - Design of the Solution
Unit 3 - Design of the Solution Cont.
Data is raw facts and figures that are only meaningful when put into context.

Data can arise in two ways - Directly or indirectly.
Direct data is collected for a specific purpose (eg. When buying food at a supermarket, the barcode is scanned and data about the product is read).
Indirect data is derived from the data originally collected for a different purpose (eg. Data collected about the product at the supermarket is used as data in the stock taking database).

Data can appear in many different forms. It can be text, numbers, sound, still or moving images.

If data is input into a system incorrectly, the information output will be incorrect (GIGO - Garbage In, Garbage Out).
For example, if a student's mark is entered incorrectly into a program for calculating grades, the grade will be calculated using incorrect data and the output student's grade will be incorrect.


Data can be provided in several formats, including:
Paper forms
- Application forms, questionnaires, etc.
Podcasts
- Audio files that can be played on audio devices.
Data from other systems
- Output from one system, that can be an input for another system.
Website information
- Information provided from a website.

Techniques for improving the
plausibility
of data being inputted into a system are called
validation techniques
. Validation techniques don't check that data is true, only that it is valid and plausible.
Techniques for improving
accuracy
of data being inputted are called
verification techniques
. The accuracy of data being inputted affects the output's quality.

Types of validation check include:
Presence check
- Ensures data has been entered into a field.
Length check
- Ensures data is of the correct length in a field.
Type check
- Ensures data being entered is of a certain type (eg. alphabetical, numerical).
UNIT 1 -
An ICT System
and its
Components
UNIT 2 -
Data and
Information
UNIT 3 -
Design of
Solution
There are several factors that affect the quality of information, including:
Accurate - If information is not accurate enough for the reader, then the information is not useful.
Relevant -
Up to date -
Timely -
Understandable -
Complete -
UNIT 4 -
Input Devices
and Media
Unit 4 - Input Devices and Media
The perfect input method should be
automatic
- and therefore less trouble for the user,
fast
so it can keep up with demand if high,
cheap
so it can be used by individuals as well as businesses, and
accurate
so there are less mistakes.

Manual input devices, and their benefits and drawbacks:
Keyboard
- They are
simple to use
, with a
universal layout
and no
extra training needed
for the user. However it is easier to make
mistakes
, is
slow
compared to other devices and
health issues
such as RSI can arise.
Speech recognition
- It is
accurate
,
faster than typing
,
relatively cheap
to buy the software/hardware, and can
prevent RSI
. However, it can be
less accurate
with background noises and accents, and can be
frustrating
for beginners to use.
Graphics tablet
- Provides a
natural
way to draw with a stylus like a pen, more
fluid
shapes can be drawn. However, it isn't the best option for tasks requiring
pointing and clicking
.

Other manual input devices include
digital cameras
,
webcams
,
computer mice
,
joysticks
and
scanners
. Some of these are more suited to some tasks than others.
Unit 4 - Input Devices and Media Cont.
Unit 4 - Input Devices and Media Cont.
MICR
-
Magnetic Ink Character Recognition
is mostly used as a security measure on
bank cheques
, as it is
expensive
technology but is
difficult to forge
. The ink can be
read very quickly
, and
isn't affected by folds
in the cheque paper.
OCR
-
Optical Character Recognition
is used in conjunction with a scanner to scan images of handwritten documents and recreate them as text. OCR is
cheap
, and is often
used in post offices
to automatically read addresses on letters. The software can be
quite accurate
, provided the
writing is clear
.
Magnetic Strip Recognition
- Magnetic strips are used commonly on
credit cards
along with
PIN numbers
. It is
quick
to swipe the card and is
hard to forge
the magnetic strip, although not impossible.
Automatic input devices:
Barcode recognition
- Barcodes are useful in
shops
, as it provides a
quick
and
cheap
method of cataloguing items for sale, and attaching a price to the items for use at checkout. Barcodes can also be scanned at angles. However, if a barcode is partly damaged/missing, the item number will have to be manually typed in, and new products have to be manually added to the stock database.
OMR
-
Optical Mark Recognition
uses pen marks on specially designed papers to record answers. OMR is often used in multiple
choice school tests
or
lottery tickets
.
Large volumes
of papers can be read at once
automatically
by a machine. However, only
tick box style questions
can be used, and
clear instructions
need to be given to those filling in the paper. Issues can arise if the paper becomes folded or isn't filled in correctly.
UNIT 5 -
Storage Devices
and Media
Unit 5 - Storage Devices and Media
Storage is divided into two categories -
primary
and
secondary
.

Primary storage
is internal on a computer, and consists of two components,
ROM
and
RAM
.
ROM
is
Read Only Memory
, which is
volatile
/temporary (all data is lost when the computer is switched off).
RAM
is
Random Access Memory
, which is
non volatile
/permanent (memory is stored is stored and not lost when the computer is switched off).

Secondary storage
is mainly external on a computer, and is
RAM
which is
non volatile
/permanent.

When comparing storage devices and their performance, it is important to consider:
Storage capacity
- The
more data
that can be saved on the device the better.
Storage density
- The
more storage
you can store in a
smaller space
, the better.
Access time
- The
shorter the time
taken to
access specific data
, the better.
Transfer rate
- Data needs to be transferred onto the
ROM
for it
to be read
.
Physical size
- The
smaller and lighter
, the better for portability.
Portability
- Devices can be
transported
to different places, and
should be removable if used for backups
.

Unit 5 - Storage Devices and Media Cont.
Storage devices, their average sizes and their benefits and drawbacks:
Floppy Disks
-
1.44 MB
. They are
cheap
to purchase, but have a
small storage capacity
and
slow transfer rate
. They are
not commonly used
any more.
Hard Drives
-
Variable, 100 GB to 2 TB
. They have a
high storage capacity
,
high transfer rate
and are
great for storing backups
. However
price increases
as storage capacity increase.
Optical Drives
-
CD - 700 MB, DVD - 4.7 GB
. They are
cheap
to buy, have a
decent sized storage capacity
, and are great for distributing or transferring files. However, they have a
slow transfer rat
e. CD-RWs are rewritable, CR-Rs are rewritable only once.
Magnetic Tape
-
800 GB
. Magnetic tape is
ideal for backups
, located away from the business. Useful for a large business backups. However there are
slow transfer rates
.
Unit 5 - Storage Devices and Media Cont.
Memory Sticks
-
Variable, 2 GB to 64 GB
. They have a
large storage capacity
, are
relatively cheap
and are
portable
so are great for transferring files. However they are
easily lost
with their small size, and have a
slow transfer rate
compared to hard drives.
Memory Cards
-
Variable 4 GB to 64 GB
. Their
small size
means they are ideal for use with cameras and other recording devices. However, since they are so small they can be
lost easily
.
Cloud storage
-
Variable
- The size of cloud storage varies according to what the user needs and how much they pay for. Cloud storage is
accessible from any location
(providing there's an
internet connection
), and this makes it
ideal for backups
. It is
good value for money
.
8 BITS
=
1024 KILOBYTES
1024 KILOBYTES
=
1 MEGABYTE
1024 MEGABYTES
=
1 GIGABYTE
1024 GIGABYTES
=
1 TERABYTES
UNIT 6 -
Output Devices
and Media
Unit 6 - Output Devices and Media Cont.
Dot Matrix - Dot matrix printers work by forming characters on papers from a number of small dots. They can use both multipart and continuous stationery, and are reliable printers. However, noise levels are high and characters can appear blurry. Also, it is an unsuitable printer for graphic printouts, and limited colours are available.
Thermal - Thermal printers work by selectively heating coated thermal paper when the paper passes over the thermal print hear. They are quick to print, and are silent when running.
Plotter - A plotter is used to print maps, graphs and designs to scale. There are two types of plotter printers - drum plotters and flat bed plotters.

Unit 6 - Output Devices and Media
Output media
includes:
Hard copies
- Content originally on a computer (eg. Word document) printed off by a printer.
Soft output
- Screen display.
Output in a digital format
- Used as the input into another system.
Sound
- Music, sound effects, etc.

Output devices
include:
Printers
- Inkjet, Laser, Dot-Matrix, and Thermal printers.
Screens
- Also known as Monitors.
Plotters
- A type of printer used to print graphs, maps, plans, etc. to scale.
Speakers
- Outputs sound media, speakers and headphones.
Unit 6 - Output Devices and Media Cont.
To set up certain printers,
drivers
need to be installed on the computer. These are usually supplied with the printer. They can also be found online.

Types of printer, and their benefits and drawbacks:
Inkjet
- Inkjet printers work by spraying ink onto paper. They produce almost
professional quality
prints and are
very quiet
when printing, with
low initial costs
. However,
ink prices are high
and ink can
smudge
, ruining the print.
Laser
- Laser printers use laser beams to form images on paper. They have a
high printing speed

and reliability
,
ink doesn't smudge
and
supplies last longer
. However,
initial costs are high
and
colour laser printers are expensive
. Laser printers are also
noisy
.
UNIT 7 -
Systems and
Applications
Software
Unit 7 - Systems & Applications Software
Software
is divided into
two categories
-
Systems software
and
Applications software
.

Systems software
is any computer software that
manages and controls the hardware
, which
enables the applications software to function
. Systems software is made up of a number of programs, including the
Operating System
and
Utilities
such as
file management
,
anti-virus
and
disk defragmentation.

Applications software
allows the
computer to be applied to a particular problem
. Examples of applications software include
word processing
,
spreadsheet and presentation software
.

Types of interfaces include:
Command Line Interface - Commands need to be typed in a specific way to be understood by the computer. A CLI takes up less space on the hard drive, but specialist language and knowledge of syntax is needed.
Natural Language Interface - An interface that allows the user to interact with spoken language. Requires no specialist language but may be affected by accents/dialects.

Unit 7 - Systems & Applications Software Cont.
Graphical User Interface - An interface which allows the user to communicate with the computer through use of icons, menus and shortcuts. A GUI requires no specialist language (unlike a CLI), and is much easier to use as there is a mouse for pointing and clicking. However, a GUI requires more space on the hard drive of a computer, and is more of a strain on the CPU of the computer also.
Menu Driven Interface - An interface where the user is given a list of options and they choose an option using their keyboard to type the letter/number of their selection. A MDI is simple to use and understand, and requires minimal clicking. However, this interface is only suitable if there are limited options.


Utilities are systems software which help the user perform specific tasks. Examples of utilities include file converters, virus scanners, file explorers, defragmenters, uninstallers, and file compressors.

Operating systems are software that control the hardware of the computer and is used to control the applications software. Examples include Windows, Mac OS, Android, Linux.
COMPUTER
HARDWARE
OPERATING
SYSTEM
GUI
FILE
MANAGEMENT
BROWSER
UTILITIES
SPREADSHEET
WORD
PROCESSOR
PRESENTATION

Unit 7 - Systems & Applications Software Cont.
Types of software include:
Generic software - This is general purpose software, for example presentation software, word processing software.
Specific software - This is software that is used to solve problems for one specific purpose, for example a piece of CAD/CAM software.
Bespoke software - This is software that has been written to fit a user's requirements. This way, the software exactly fits the client's needs, however it takes more time to create a custom piece of software.
Off the shelf software - This is software that has not been developed for any particular user, for example Microsoft Office products. Off the shelf software is cheaper than bespoke software but is not specifically made to fit user requirements.
Integrated - An application package consisting of several generic
softwares, for example Microsoft Office.

Wizards - They give the user help when using software, for example Clippy in Microsoft products.
Macros - They allow the user to automate tasks. They can be written by hand or recorded from keystrokes. They can then be run and this saves time.
UNIT 8 -
Implementation
of an IT
Solution
Unit 8 - Implementation of an IT Solution
When designing the output:
The layout should match current documents to keep continuity.
Information stored must be what the user wants.
Information must be organised sensibly.
The printouts must have a professional and consistent feel to them.
The output must look good in black and white as well as in colour.
Graphical User Interface
Command Line Interface
Menu Driven Interface
UNIT 9 -
Testing of an
IT Solution
Unit 9 - Testing of an IT Solution
When creating your solution, look closely at the design of the solution and place it in a logical order.
How the data is entered into the system - human computer interfaces.
How easy is the the data capture method to use?
Is it user friendly, clear and simple?
Does it match the needs of the user or client?
Is there enough navigation on the screen?
How is help/support dealt with?
Control mechanisms of the solution - validation and verification.
What validation checks/verification methods have to be carried out?
How the data is processed and organised - processing.
What existing methods are in place?
Are you adapting these methods or creating a new one?
How is the data going to be organised?
What is going to be the output and hos is it going to look - reports.
Is the output in the form of reports, charts and graphs, or document form?
An overview of the solution.
Unit 8 - Implementation of an IT Solution Cont.
When creating the solution, you should find the most appropriate tools for the task. This could mean using more than one package to solve the problem.

Using a generic package to create an effective solution will be helpful when it comes to the exam.
To test a solution and ensure a client's system requirements are met, a test plan is used.
A test
An example of a test plan
UNIT 10 -
Evaluation of
an IT Solution

Unit 8 - Implementation of an IT Solution Cont.
When creating the solution, you should find the most appropriate tools for the task. This could mean using more than one package to solve the problem.

Using a generic package to create an effective solution will be helpful when it comes to the exam.
INPUT
PROCESS
OUTPUT
STORAGE
Unit 2 - Data and Information Cont.
Data on an ICT system needs to be encoded into a machine readable format, so it can be understood by the system. Types of encoding include:
Pictures into vector graphics (eg. jpg) or bitmapped (eg. bmp).
Sound into wave (eg. mp3 or wav).
Text into documents (eg. doc or pdf).
Video into video files (eg. avi or mpeg).

Data on an ICT system can be coded rather than being entered in full. This has multiple benefits, including reducing the size and storage space of the data, making mistakes less likely through less chance of misspelling, and being quicker to enter. For example, a clothing shop using S for Small, M for Medium, L for Large, etc.

Information is data that has been processed into a form that has meaning and context. For example, the numbers 5, 9,27, 36 and 49 as average test scores for different classes of a school is information, as these numbers have been processed by a system to create an average, which has context and is meaningful.
Full transcript