Transcript GCSE ICT - ICTRESOURCES.net

GCSE ICT
For those that don’t know?
My Name is Mr Hall
I am Director of Learning for:
• ICT,(GCSE/OCR Nationals/Cambridge Nationals)
• Computer Science
• Business Studies
What is the course made up of?
B061-theory leading to external exam
B062 –practical task-controlled assessment
B063-theory leading to external exam
B064-practical task controlled assessment
B061-theory leading to external exam
Today we will be starting the theory associated
with B061 ICT in today’s world
What you will learn
•
•
•
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The different types of ICT system and their uses
The difference between hardware and software
The hardware components of ICT systems
The software used in ICT systems
The different types of ICT system and
their uses
ACTIVITY 1
Make a list of three items that you own or use
regularly ( apart from your laptop or PC)
– that use ICT and that you think you could not
do without, and then write down what your life
would be like without them.
ICT systems
What is a computer?
Charles Babbage’s Difference Engine
A computer is a programmable machine that follows a set of instructions.
Early computers were mechanical with levers and cogs such as Charles Babbage’s
Difference Engine which was an automated, mechanical calculator, large enough to fill a
small room!
ICT systems
• Babbage’s Analytical Engine was designed
to be a general purpose computer but
was never built, some believe, because
the technology of the day was either not
good enough or too expensive.
• Babbage was still working on the design
when he died in 1871.
• A working model was built in 1992 and
can be seen in the Science Museum in
London.
Watch video on this now
Digital computers
• Modern computers are not mechanical but are electronic and,
while some analogue computers are used in universities for
research, most computers now are digital.
• Computers can follow or execute a set of prewritten or recorded
instruct ions, called a program, and respond to commands entered
by a user.
• All computers used today have the same basic structure, although
the way the components are arranged in the structure differs
depending on the use to which the computer will be put.
The photos show some examples of modern computers:
Show brief history
of computers video
Keywords
Write out in the back of your GCSE text books
the following keywords and their definitions
Analogue
Analogue signals are continually variable and even small
fluctuations in the signal are important.
Analogue systems use continuous ranges of values to represent
information.
Digital
Digital signals have discrete values such as on/off, 1 or 0.
Inbetween values are not used.
Personal computers
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Used in schools at home- you use for tasks such as writing reports or letters in a wordprocessor, doing calculations or data modelling in spreadsheets, photo and video editing or
playing games. Often connected together on a network.
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The internet which also allows PC’s to be used for searching the World Wide Web,
sending and receiving email messages, accessing chat rooms or instant messaging, writing
blogs and using social networking sites.
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PC’s include netbooks, laptops, notebook computers, palmtops, desktop computers,
tablet computers, PDAs and handheld computers.
Smart phones can also carry out many of the tasks normally associated with personal
computers with the added advantages of being able to keep in contact with friends by text
message or telephone, having an inbuilt camera and playing music or video files or using
applications when out and about away from home.
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Pc’s are often found in businesses and are used for general tasks such as running
database management systems, business spreadsheets and for specialised business
purposes such as computer-aided design and computer-aided manufacture such as making
cars or televisions.
Also, PC’s can be used for capturing and monitoring data received from sensors such as
for recording temperatures and pressures of the weather.
Types of computer -Activity 2
• For each of the different types of computer
shown, write down some typical tasks that it
would be most suitable for.
Other types of computer system
• Supercomputers and mainframes
• Embedded computers
Supercomputers
• Show titan super computer video
Mainframes
• Show mainframe video
Embedded computers
Activity 3
• Use the internet to find out what is meant by
‘microcomputer’ and write down the names
of two famous makes of microcomputer.
http://www.teach-it.com/gcse/hardware/types/teacher/types_theory.htm
http://computer.howstuffworks.com/10-types-of-computers.htm
http://en.wikipedia.org/wiki/Personal_computer
http://www.webopedia.com/TERM/P/personal_computer.html
http://www.historylearningsite.co.uk/personal_computer.htm
These provide explanations and descriptions of different types of
computers.
More GCSE ICT Keywords…
• Write out the following keywords in the back of your text book.
• NB:You will need to learn these for revision for your exam
Personal computer
These include netbooks, laptops, notebook computers, palmtops, desktop computers,
tablet computers, PDAs and handheld computers. Used for web searching, email,
running applications, e.g. word-processing, spreadsheets, databases, and many other
software applications in homes and offices
Mainframe computer
Large computers used in banks, insurance firms where very large amounts of data
have to be
processed quickly
Supercomputer
Very fast computers used in universities and other areas where complex calculations
are needed and speed of calculation is important
Student task:gcse ict keywords
Write out the following keywords in the back of your text book.
NB:You will need to learn these for revision for your exam
Input
Entering data into a computer system is input.
Processing
Data is converted it from one form to another. This is done
by following a set of instructions and commands.
Output
When the results of processing are shown, this is output.
Storage
Data is kept or recorded while waiting to be used
or for future use.
Hardware
Nb copy this diagram into the front of your gcse ict text books
• Whatever the type of computer, it will always
have the same basic hardware structure.
• There will also be all the components, nuts, bolts,
screws, wiring and connectors, etc. to allow all
the other components to work together but
essentially a computer system consists of INPUTS,
OUTPUTS, PROCESSING and STORAGE devices
and data flows around the computer system from
one to another as shown in the following diagram
computer systems
https://youtube.googleapis.com/v/kbhQ7GA9E_s
A computer system
input
Nb copy this
diagram into the
front of your gcse
ict text books
processing
Main or internal
memory
Backing storage
output
Activity 4
• Imagine that you have a list of your friends and
want to keep it on your laptop.
• You carry out three tasks:
1.typing in the list,
2.sorting the list into alphabetical order of name
3.printing yourself a list to keep at home.
Identify which of the three tasks is input, output and
processing.
More components in a computer system..
A hub
A “NIC”
A router
other devices will be present :
components needed to connect
the computer systems to others on
a network.(nic)
communication devices such as
modems, network interface cards,
routers and hubs. Other
connection systems may also be
present, e.g. USB interfaces.
Usb pen drive
processor
Mouse
Student task
• Find out how a Network interface card works
• Find out how a router works
• Find out how a processor works
Nb :Do not copy and paste and write out in your
text books please so that you have a bank of
notes to revise from
Keywords to write out…
Network
When computers are connected together so that they can share data and
devices such as printers, they are said to be in a computer network.
Interface
This is where data is transferred between computer devices or between
people and computers.
USB interface
The Universal Serial Bus interface was designed for use on personal
computers to connect peripheral devices such as printers, keyboards and
flash drives. It is now commonly used to connect other devices such as
cameras. USB connections are also now found on many other devices such
as PDAs, mobile phones and can also be used to charge batteries.
Peripheral device
Any device that is not actually part of the computer but is attached to
a computer is called a peripheral device. Peripheral devices are seen as
expanding the system and include scanners and printers.
Nb Write out in the back of your gcse it text book
Activity 5
Find out what a ‘user interface’ is and what it is for.
Write out the answer in the front of your book
Communication devices
Modem
This device encodes digital information on to an analogue signal.
Often used to send digital data along ordinary telephone lines
Network interface cards
This device is often just called a network card or NIC; these provide the
electronic circuitry for computers to communicate on a network Hub This
device connects different networks sections
Routers and switches
These devices connect different networks and can be used to control
where the data is sent. They are often found in homes and used for
connecting to the internet
USB interface
This is used to connect a computer with another device such as a flash
memory device
Nb:Write the following notes into the front of your GCSE ICT text book Neatly-You will need to
revise these
Processing data(1)
• Processing in computer systems is carried out by the Central Processing Unit(CPU).
•
The CPU is a collection of electronic circuits that carry out, or execute, instructions
either in a program or which are entered by the user and which make decisions
using the instructions.
• The instructions have to be entered into the computer, stored in the computer’s
main memory, or in some special memory actually inside the CPU itself, and the
results output from the computer for every task that the computer is asked to
perform.
• If the computer is switched off, then the data that users need to carry on
with their work when it is switched back on and all the instructions needed
to start and operate the computer have to be kept on a storage device.
Nb:Please write out the above notes in your text books neatly
Processing data (2)
• If this data was not stored safely, the users would have to redo all of their
work every time they switched off and restarted the computer; if the
instructions to start the computer were not stored, then it wouldn’t restart!
• The components used for input include not only the familiar devices such
as the mouse and keyboard found in personal computer systems but also
more specialised input devices such as microphones designed to capture
sounds, suck and puff switches used by those people unable to use their hands
to manipulate a keyboard or mouse and the input devices used in computer
games (such as wireless games controllers) and at supermarket terminals.
Nb:Please write out the above notes in your text books neatly
Input devices
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Mouse
Keyboard
Microphone
Barcode reader
Chip and pin reader
Web cam
Sensor
Remote control
Nb:Write out the above outputs from a computer as they will come up in an exam
Student activity 6
• Persons with physical disabilities often have difficulties
using computers in schools to do their work.
• Find out about the specialised equipment and
software that can help those people to use computers
WEBLINK:
http://tinyurl.com/jvjz458
Output devices
Speaker:
produce sounds
Monitor :
This is the ‘screen’ or ‘display’ found on most computer systems and used to see the results
of processing.Monitors are now nearly all LCD with flat screens, and the older-style ‘vacuum
tube’ displays are no longer used. They are found in all shapes and sizes but ‘widescreen’
monitors are best for viewing movies
Printer:
Printers produce copies of the results on paper – this is ‘hardcopy’
Nb:Write out the above outputs from a computer as
they will come up in an exam
Storage devices
The storage of data and instructions is important because the CPU needs to be able
to access the data or instructions quickly and easily and a user needs to be able to
store their work for future use.
A computer system has two types of storage for its data:
1.the main memory (also called internal memory(Ram and Rom),where the data that
is being used, is about to be used or has just been used by the CPU is kept.
2. backing storage for longer-term storage of data.
Nb:Write out the above outputs from a computer as they will come up in an exam
Activity 7
The size or capacity of storage devices is measured in
bytes.
• (a) Find out what is meant by a ‘byte’.
• (b) Find out how many bytes make up a kilobyte
(Kb), a megabyte (Mb) and a gigabyte (Gb).
Nb:Write out the above outputs from a computer as they will come up in an exam
Write out the following notes in
your GCSE Text books
Rom memory
•
used to store data or instructions that do not need to be changed ie the instructions
needed when the computer is first switched on.(bootstraploader for example) When a
computer is first switched on, the CPU does not know what to do so there are a few
instructions stored in ROM that tell it where and how to find the instructions to get
started.
•
ROM is a type of memory from which data can be read but which cannot usually be
changed or erased such as the data that a computer needs when starting up or the
instructions in a washing machine. users must not be able, or have any need, to alter
these instructions because if they do then
the machines would not work.
•
Also, ROM does not lose its data when the electrical power is switched off. It is said to be
nonvolatile, i.e. keeps its data without the need for electrical power. Special types of ROM
can have the data changed, e.g. an EEPROM (Electrically Erasable Programmable Read
Only Memory) can be erased and reprogrammed and there are other types that are used
for specialised purposes such as storing the configuration details of a router.
•
Sometimes, the initial startup instructions of a computer (called the BIOS)
are stored in EEPROMs so that they can be updated in the future.
memory
Ram memory
Show how ram memory works video
•RAM does not keep any data if its power supply is switched off (it is said to be
volatile) .
•Data in RAM can be accessed much faster than in ROM. More importantly, the data
in RAM can be accessed quickly wherever it happens to be stored.
•RAM is used to store the data and instructions such as the operating system that
the CPU is currently using, and the data and software applications being used by the
user.
•When switched on, the instructions stored in its ROM will be used to start
it(bootstraploader) and load the operating system from the hard disk into its RAM.
When it is ready for use, a user may start an application like a web browser and this
will also be loaded from the hard disk into RAM ready for use.
Write out the following notes in your GCSE Text books
Ram memory
Memory keywords
• ROM
Read Only Memory is a permanent storage area of
memory that does not lose its data when power is
turned off – it is said to be nonvolatile. Data can only
be read from ROM, not written to it.
• RAM
Random Access Memory loses its data when power is
turned off – it is said to be volatile – but can be written
to as well as read from.
• BIOS
The Basic In Out System that is needed to tell the
computer what to do on startup
Write out the following notes in your GCSE Text books
Different types of memory storage
• Flash memory
• Removable storage
media(cd/cdrw/dvdr/dvdrw/blueray etc)
5.3 Storage Devices
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Storage device stores information to be
recalled and used at a later time
Storage device consists of:
•Storage medium
•Storage device
Three major technology types for
information storage:
•Magnetic
•Optical or laser
•Flash memory
©2003 The McGraw-Hill
SimNet
Concepts
Companies
Support CD: “Storage Concepts”
Storage Medium Terms
– Byte
– Kilobyte (KB)
– Megabytes (MB)
– Gigabytes (GB)
– Terabytes (TB)
– Petabyte (PB)
– Exabyte (EB)
©2003 The McGraw-Hill
Companies
= 8 bits
≈ 1 Thousand Bytes
≈ 1 Million Bytes
≈ 1 Billion Bytes
≈ 1 Trillion Bytes
≈ 1 quadrillion Bytes
≈ 1 quintillion Bytes
Magnetic and Optical Storage
©2003 The McGraw-Hill
p. 5.142 & 5.144 Fig. 5.13 & 5.16
Companies
Magnetic Storage Devices: Internal
Magnetic Hard Disk
•
Magnetic storage devices can be
either internal or external
•
•
Internal magnetic hard disks are
fixed inside the system unit
External magnetic hard disks are
portable
©2003 The McGraw-Hill
SimNet
Concepts
Companies
Support CD: “Removable Disks”
Magnetic Storage Devices: Internal
Magnetic Hard Disk
• Internal hard disk is a magnetic
storage device with
• One or more thin platters that store
information sealed inside the disk drive.
• Read/write heads access the information
on surface
• Heads read information while copying it
from disk to RAM
• Heads write information when copying it
from RAM to disk
©2003 The McGraw-Hill
Companies
Magnetic Storage Devices: External
Magnetic Hard Disk
• External hard disks are magnetic
storage media which are portable
storage units that you can connect
to your computer as necessary
• Great for backup storage devices
• Ability to transport your hard disk
from one computer to another
©2003 The McGraw-Hill
Companies
Hard Drives
• Long term storage system and
application software
• Operating system and
application software are
copied from the hard disk to
memory
• Capacity measured in
gigabytes
©2003 The McGraw-Hill Companies
Floppy Disks and Zip Disks
• Removable magnetic storage media
come in two basic types:
– Traditional floppy disks
– Zip disks
• These storage media are useful for:
– Storing files for backup or security
purposes
– Transferring files from one computer to
another
©2003 The McGraw-Hill
Companies
Removable Magnetic Storage: Floppy
Disk
• Floppy Mylar disk
– Housed inside a hard plastic
casing
– Thin, flexible plastic disk
• 3.5 inch floppy disks
– also called floppies, diskettes,
floppy disks
– Holds about 1.44 megabytes of
information
• High-capacity disks
– Zip® disk
p. 5.144 Fig. 5.15
©2003 The McGraw-Hill Companies
Removable Magnetic Storage: Zip Disk
• High capacity plastic platter disk
– Called removable hard disks
– Provide a higher storage capacity than Mylar disks
• Example - Zip® disk with capacity of 100MB, 250MB,
and 750MB
©2003 The McGraw-Hill
Companies
Optical Storage
• CDs
• DVDs
• Both are optical storage
and have three formats:
– Read-only
– Write-once
– Read-and-write
©2003 The McGraw-Hill Companies
Optical Storage Media
• Read-Only
 CD-ROM
 DVD-ROM
• One-Time Writable
 CD-R
 DVD-R
 DVD+R
SimNet
• Fully Read-and-Write
 CD-RW
 DVD-RW or DVD+RW
or
DVD-RAM
Concepts Support CD: “CDs and DVDs”
©2003 The McGraw-Hill
Companies
Flash Memory Cards
• Flash memory cards have highcapacity storage laminated
inside a small piece of plastic
• Flash flash memory cards do not
need a drive with moving parts
to operate
©2003 The McGraw-Hill
Companies
Flash Memory Talk
•
•
•
•
CompactFlash (CF)
xD-Picture Card (xD)
SmartMedia (SM) Card
SecureDigital (SD) card and
MultiMediaCards (MMC)
• Memory Stick Media
©2003 The McGraw-Hill
Companies
Flash Memory Card Readers
• Some devices have flash memory slots into
which you slide your flash memory card
• Other devices can use an external flash
memory card reader in order to transfer
information
• A flash memory drive is a flash memory
storage medium for a computer that is
small enough to fit in your pocket and
usually plugs directly into a USB port
©2003 The McGraw-Hill
Companies
Networking
• Computer network A collection of computing
devices that are connected in various ways in
order to communicate and share resources
Usually, the connections between computers
in a network are made using physical wires or
cables
However, some connections are wireless, using
radio waves or infrared signals
15-57
Networking
• The generic term node or host refers to any
device on a network
• Data transfer rate The speed with which data
is moved from one place on a network to
another
• Data transfer rate is a key issue in computer
networks
15-58
Networking
• Computer networks have opened up an entire
frontier in the world of computing called the
client/server model
15-59
Figure 15.1 Client/Server interaction
Networking
• File server A computer that stores and
manages files for multiple users on a network
• Web server A computer dedicated to
responding to requests (from the browser
client) for web pages
15-60
Types of Networks
• Local-area network (LAN) A network that
connects a relatively small number of
machines in a relatively close geographical
area
15-61
Types of Networks
• Various configurations, called topologies, have been
used to administer LANs
– Ring topology A configuration that connects all nodes in a
closed loop on which messages travel in one direction
– Star topology A configuration that centers around one
node to which all others are connected and through which
all messages are sent
– Bus topology All nodes are connected to a single
communication line that carries messages in both
directions
15-62
Types of Networks
Figure 15.2 Various network topologies
• A bus technology called Ethernet has become the industry
standard for local-area networks
15-10
Types of Networks
• Wide-area network (WAN) A network that
connects two or more local-area networks over a
potentially large geographic distance
Often one particular node on a LAN is set up to serve as a
gateway to handle all communication going between that
LAN and other networks
Communication between networks is called
internetworking
The Internet, as we know it today, is essentially the
ultimate wide-area network, spanning the entire globe
15-64
Types of Networks
• Metropolitan-area network (MAN) The
communication infrastructures that have been
developed in and around large cities
15-65
So, who owns the Internet?
Well, nobody does. No single person or
company owns the Internet or even controls it
entirely. As a wide-area network, it is made up
of many smaller networks. These smaller
networks are often owned and managed by a
person or organization. The Internet, then, is
really defined by how connections can be
made between these networks.
15-66
Types of Networks
Figure 15.1 Local-area networks connected across a distance to
create
15-67 a wide-area network
Internet Connections
• Internet backbone A set of high-speed
networks that carry Internet traffic
These networks are provided by companies
such as AT&T, GTE, and IBM
• Internet service provider (ISP) A company
that provides other companies or individuals
with access to the Internet
15-68
Internet Connections
• There are various technologies available that you can use to
connect a home computer to the Internet
– A phone modem converts computer data into an analog audio
signal for transfer over a telephone line, and then a modem at the
destination converts it back again into data
– A digital subscriber line (DSL) uses regular copper phone lines to
transfer digital data to and from the phone company’s central
office
– A cable modem uses the same line that your cable TV signals come
in on to transfer the data back and forth
15-69
Internet Connections
• Broadband A connection in which transfer speeds
are faster than 128 bits per second
– DSL connections and cable modems are broadband
connections
– The speed for downloads (getting data from the Internet
to your home computer) may not be the same as uploads
(sending data from your home computer to the Internet)
15-70
Packet Switching
• To improve the efficiency of transferring information over a
shared communication line, messages are divided into fixedsized, numbered packets
• Network devices called routers are used to direct packets
between networks
Figure 15.4
Messages
sent by
packet
switching
15-18
Open Systems
• Proprietary system A system that uses technologies
kept private by a particular commercial vendor
One system couldn’t communicate with another, leading to
the need for
• Interoperability The ability of software and hardware
on multiple machines and from multiple commercial
vendors to communicate
Leading to
• Open systems Systems based on a common model
of network architecture and a suite of protocols used
in its implementation
15-72
Open Systems
• The International
Organization for
Standardization (ISO)
established the Open
Systems Interconnection
(OSI) Reference Model
• Each layer deals with a
particular aspect of
network communication
Figure 15.5 The layers of the OSI Reference Model
15-73
Network Protocols
• Network protocols are layered such that each
one relies on the protocols that underlie it
• Sometimes referred to as a protocol stack
Figure 15.6 Layering of key network protocols
15-74
TCP/IP
• TCP stands for Transmission Control Protocol
TCP software breaks messages into packets, hands
them off to the IP software for delivery, and then
orders and reassembles the packets at their
destination
• IP stands for Internet Protocol
IP software deals with the routing of packets
through the maze of interconnected networks to
their final destination
15-75
TCP/IP (cont.)
• UDP stands for User Datagram Protocol
– It is an alternative to TCP
– The main difference is that TCP is highly reliable,
at the cost of decreased performance, while UDP
is less reliable, but generally faster
15-76
High-Level Protocols
• Other protocols build on the foundation
established by the TCP/IP protocol suite
– Simple Mail Transfer Protocol (SMTP)
– File Transfer Protocol (FTP)
– Telnet
– Hyper Text Transfer Protocol (http)
15-77
MIME Types
• Related to the idea of network protocols and
standardization is the concept of a file’s MIME
type
– MIME stands for Multipurpose Internet Mail
Extension
– Based on a document’s MIME type, an application
program can decide how to deal with the data it is
given
15-78
MIME Types
Figure 15.7
Some protocols
and the ports
they use
15-79
Firewalls
• Firewall A machine and its software that
serve as a special gateway to a network,
protecting it from inappropriate access
– Filters the network traffic that comes in, checking
the validity of the messages as much as possible
and perhaps denying some messages altogether
– Enforces an organization’s access control policy
15-80
Firewalls
15-81
Figure 15.8 A firewall protecting a LAN
Network Addresses
• Hostname A unique identification that
specifies a particular computer on the Internet
For example
matisse.csc.villanova.edu
condor.develocorp.com
15-82
Network Addresses
• Network software translates a hostname into
its corresponding IP address
For example
205.39.145.18
15-83
Network Addresses
• An IP address can be split into
– network address, which specifies a specific network
– host number, which specifies a particular machine in that
network
Figure 15.9
An IP address is
stored in four
bytes
15-84
Domain Name System
• A hostname consists of the computer name followed
by the domain name
• csc.villanova.edu is the domain name
– A domain name is separated into two or more sections
that specify the organization, and possibly a subset of an
organization, of which the computer is a part
– Two organizations can have a computer named the same
thing because the domain name makes it clear which one
is being referred to
15-85
Domain Name System
• The very last section of the domain is called its toplevel domain (TLD) name
15-86 15.10 Top-level domains, including some relatively new ones
Figure
Domain Name System
• Organizations based in countries other than the
United States use a top-level domain that
corresponds to their two-letter country codes
Figure 15.11
Some of the top-level domain
names based on country codes
15-87
Domain Name System
• The domain name system (DNS) is chiefly
used to translate hostnames into numeric IP
addresses
– DNS is an example of a distributed database
– If that server can resolve the hostname, it does so
– If not, that server asks another domain name
server
15-88