These are ICT from my teacher. GOD BLESS HER!! Thanks to her i might have passed ICT!!

HideShow resource information
  • Created by: mar-rii
  • Created on: 07-06-09 18:49
Preview of Networks

First 769 words of the document:

A useful revision resource for understanding networks, the internet & email is BBC Bitesize URL:
A computer which isn't connected to a network is known as a stand-alone computer. In organisations (businesses,
schools, hospitals, etc) most computers are connected together on a computer network. There are 2 main types of
network ­ LAN (Local Area Network) & WAN (Wide Area Network).
LAN (sometimes called "Intranets"):
When the computers in a network are fairly close to one another e.g. in the same office block or in 2 or 3 buildings on the
same site (like at our school), they can be joined together either by cables or wireless and this type of network is called a
Local Area Network (LAN).
Users of the LAN can share and use the same resources at the same time. They can share files, software, hard disks and
peripherals (e.g. printers). Users can also use the LAN to communicate with each other e.g. by email. Data can be
transmitted very quickly between networked computers.
A file server is often used to store each person's data files. This means that people can log onto any machine on the
network and access their files. They are not restricted to just one machine. Another advantage of having all of the files
stored in one place is that a back up copy of every user's files can be made easily.
To log onto a LAN, you usually need a user name and password. The user name identifies you to the file server so that it
can 'serve' you the correct files. The password ensures that the user name really does belong to you.
If a business has offices, shops or factories in different places around the country or around the world they might still
want their staff to access the same information no matter where they are. It would not be possible to connect computers
together that are in different cities or countries using the LAN cables so a Wide Area Network (WAN) is needed. A WAN
is basically a number of LANs connected together. There are different ways of connecting the LANs together e.g. a
modem and the telephone cables or using fibre optic cables or satellite. By linking LANs together, the network is no
longer local to one building; it is now spread over a wide area so is called a Wide Area Network (WAN). The largest WAN
is the Internet.
Advantages of Networks:
Users can access their work from any workstation on the network as files are usually stored on a server not on
individual workstations
Software can be shared. Programs can be installed onto the server & then accessed from all workstations ­ this
can reduce the work load for the technician as it is easier & quicker to install the software & to upgrade it
Individual workstations do not need a printer as one printer can be shared by everyone ­ this saves money & can
save space
Networks can provide security as a user must have the correct password and user ID in order to be able to
access the information on the network
All users on the network can share the same connection to the internet so just one firewall can be used to
protect all the computers on the network from intruders. The firewall can be either a software or hardware
firewall or sometimes both might be used
Regular backups can be done of the whole network by the network administrator e.g. at school the whole
network is backed up every night onto magnetic tape
Users can communicate with others on the network by sending messages and sharing files
Data can be shared by all users at the same time. Many people can access or update the information held on a
database at the same time. Thus information is up to date and accurate
Why do you need both a user name and password?
User names are quite easy to guess and two people may accidentally have the same password, therefore, access the
incorrect account. This gives the computer system proof of identification. May have biometric devices instead, i.e.,
fingerprint scanner or iris scanner. May use pass card to allow access and also use a password with it.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

A weak password is one that is easy to guess. The most common password is "password". A strong password is one
which is difficult to guess. A strong password has a combination of character, i.e., letters and numbers. Hackers have
programs that guess passwords. After they have tried all words related to you, the program guesses all words in the
dictionary and the password may be guessed.…read more

Page 3

Preview of page 3

Here's a taster:

There can be data collisions as data has to travel in both directions along the cable
There is a maximum length for how long the central cable can be and therefore a limit on how many computers,
printers, etc can be connected to the network
Ring topology:
The server, workstations, printers, etc are connected in a circle (a ring).…read more

Page 4

Preview of page 4

Here's a taster:

On some networks the application software (e.g. word processor, database etc) is stored on the server
and only sent to a workstation when it is needed, on other networks every workstation has its own copy of the
application software and just the users' files are stored on the server. In a network there might be more than one server
depending on the number of users and the amount of hardware in the network e.g.,
A file server to store the files of all the users.…read more

Page 5

Preview of page 5

Here's a taster:

Internet. Browsers include an Address bar,
Bookmarks/Favourites option, a Refresh button and a History button.
Internet Service Provider (ISP)
An Internet Service Provider (ISP) is a company which connects users to the Internet. Users usually have to pay a monthly
fee for this connection and there might be different fees for different bandwidths. ISPs provide different services e.g.…read more

Page 6

Preview of page 6

Page 7

Preview of page 7

Here's a taster:

A Local Area Network (LAN) has a server and three workstations. One possible topology for this network is shown
below. Draw, name & label two other possible topologies. [6]
16) Katie in London sends an email to a friend in Paris. Describe what happens when the email is sent from Katie's
computer in London to her friend's computer in Paris. [4]
17) LANs and WANs are different types of network. Describe the features of these two types of network.…read more


No comments have yet been made

Similar ICT resources:

See all ICT resources »See all resources »