Download Lec.4.Communication software and the internet

Foundation year
Theory
Lec.4: Communication Software
Internet & Security
Computer For Health Sciences
COMP101
Lecturer: Dalia Mirghani
• A set of computers connected together so that they can
communicate is called a computer network.
• This involves installing network cards in each computer.
• Each computer is then connected through cabling to a central device
called a hub.
• The most commonly used protocol for establishing and
maintaining communication across a network is called TCP/IP or
Transmission Control Protocol / Internet Protocol.
Lecturer: Dalia Mirghani Saadabi
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There are two types of network interconnection:
• 1) Networks on which all computers have equal
status are called peer-to-peer networks.
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• 2) Certain computers provide services to other
computers, they are called servers.
• The computers that make use of the services or servers
are called clients.
• A network such as this is called a client server network.
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1. LAN
A LAN or Local Area Network is a group
of computers within the same building, or
within a group of buildings that are in
close proximity, that are connected
together.
2. WAN
A WAN or Wide Area Network is a group
of widely dispersed computers that are
connected together. These could be
across the same town, or across a country
or even across the world.
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• Internet
The internet is the collection of all computers across the
world which can access each other in some way. The links
between computers might include telephone, fiber optic
cable, radio, microwave or satellite.
Some of its main uses:
• Provide access to and share information and databases.
• Transfer and share files between computers.
• Facilitate business transactions.
• Share resources.
• Promote scientific co-operation between research
institutions.
• Provide a communications channel for the military.
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INTERNET ACCESS
 Using Web browser:
A web browser is the software program that is
used to display Web pages on the World Wide
Web, as Internet explorer and Firefox.
 Internet search engine:
Is an application, which helps users to locate
Web sites containing useful information and
references.
To search Information :
 A user types the description of the information
using the user interference of the search engine.
 The search engine then searches the requested
information on the WWW and returns the
results to the user.
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Some Popular Internet Search Engines
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Special Medical Search Engines…
Medical Search Engines:
Medical search engines are search engines
which are specialized in medical information,
researches, news and so on.
Here are some examples of the most popular
medical search engines…
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Lecturer: Dalia Mirghani Saadabi
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Most Popular medical website:
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• Information security refers to all the
procedures which are used to protect
information for deliberate or accidental
misuse or dissemination
• There are a number of procedures
companies and persons can take to protect
their information.
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1. Physical procedures:
• Physical access to mainframes should be restricted to
operators and systems administrators.
• The use of security cameras can also act as a deterrent.
2. Software procedures:
• Information can be stolen, altered or deleted without the
computer being physically removed. The information may
even be accessed across the Internet.
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a) Firewalls:
• It is a computer program that is installed on a
computer that connects a network to the
Internet.
• The firewall analysis the packets that pass in and
out of the network.
b) Access rights:
• Information should be classified on the basis of its
sensitivity.
• Access rights to this information should be limited to
those who need to know
• Software rights refer to the level of access
different users have to different levels of data
and information.
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c) Password policies:
• They can be required for access to a
computer system or a group of files or a
single file.
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• A computer virus is a program that is
deliberately created to cause annoyance
or alter or delete data.
• Trojan:
 A Trojan (or Trojan horse) is a virus that
hides itself inside another legitimate
program.
 When the program is used, the virus is
released and can begin its work of
replication and annoyance or damage.
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• Worm:
 A Worm is a program that replicates itself over and
over in the computer's memory until the computer
can barely function.
 One of the signs of invasion by a worm is the
slowness of computers.
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• Spread of computer viruses:
Viruses are spread in a number of ways:
– Downloads from the Internet.
– Exchange of diskettes.
– In attachments to emails and in emails themselves.
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• Anti-virus software:
• Anti-virus software scans files for pieces of code,
called signatures, which it recognizes as part of a
virus.
• Updating anti-virus software mostly involves
updating the signatures file.
• When a virus is detected, the software will
attempt to remove the virus. This is called
cleaning or disinfecting.
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• Refer to your text book, chapter (9) and answer
the following question:
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Lecturer: Dalia Mirghani Saadabi
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