Introduction to Networks and Programming Language

BACHELOR OF SCIENCE IN INFORMATION SYSTEM
FINAL TERM
Introduction to Computing
MARK JOHN P. LADO
INSTRUCTOR

Learning Topics
 Computer Networks
Overview of a network
Communication Media
Twisted pair cable
Coaxial Cable
Fiber Optic Cable

Learning Topics
 Introduction to JAVA programming
Overview of the Language
Java Eclipse GUI
Hello World

Learning Objectives
Have an impression about Computer Networks.
Determine the different Communication Media.
Identify the use of Twisted pair cable, Coaxial Cable and
Fiber Optic Cable.
Give meaning of programming language.
Describe the function of High-Level Language.
Identify and appreciate the power of High-Level Language
in programming.

Part I
Overview of a network
Coaxial Cable

Introduction to Computer Networks
Modern world scenario is ever changing. Data
Communication and network have changed
the way business and other daily affair works.
Now, they highly rely on computer networks
and internetwork.
A set of devices often mentioned as nodes
connected by media link is called a Network.

A node can be a device which is capable of
sending or receiving data generated by
other nodes on the network like a
computer, printer etc. These links
connecting the devices are
called Communication channels.

Computer network is a telecommunication
channel using which we can share data
with other computers or devices,
connected to the same network. It is also
called Data Network. The best example of
computer network is Internet.

Computer network does not mean a
system with one Control Unit connected to
multiple other systems as its slave. That is
Distributed system, not Computer
Network.

A network must be able to meet certain
criteria’s, these are mentioned below:

A network must be able to meet certain criteria’s, these are
mentioned below:
Performance
Reliability
Security

Computer Networks: Performance
It can be measured in the following ways:
Transit time : It is the time taken to travel
a message from one device to another.
Response time : It is defined as the time
elapsed between enquiry and response.

Computer Networks: Performance
Other ways to measure performance are :
Efficiency of software
Number of users
Capability of connected hardware

Computer Networks: Reliability
 It decides the frequency at which network failure
take place. More the failures are, less is the
network's reliability.

Computer Networks: Security
 It refers to the protection of data from any
unauthorized user or access. While travelling
through network, data passes many layers of
network, and data can be traced if attempted. Hence
security is also a very important characteristic for
Networks.

Twisted Pair Cable
This cable is the most commonly used
and is cheaper than others. It is
lightweight, cheap, can be installed
easily, and they support many different
types of network.

A twisted pair consists of two
conductors(normally copper), each with its
own plastic insulation, twisted together.
One of these wires is used to carry signals
to the receiver, and the other is used only
as ground reference.
Twisted Pair Cable

What are the two
types of twisted
pair cable?

Two Types of Twisted Pair
Cable
1. Unshielded Twisted Pair (UTP)
2. Shielded Twisted Pair (STP)

Unshielded Twisted Pair
(UTP)
Transmission Media

Unshielded Twisted Pair Cable
It is the most common type of
telecommunication when compared with
Shielded Twisted Pair Cable which consists
of two conductors usually covered with a
an aluminum foil.
Transmission Media

It consists of two insulating copper wires
(1mm thick). The wires are twisted
together in a helical form to reduce
electrical interference from similar pair.
Unshielded Twisted Pair Cable

Shielded Twisted Pair
(STP)
Transmission Media

This cable has a aluminum / metal foil
covering which encases each pair of
insulated conductors. Electromagnetic
noise penetration is prevented by metal
casing.
Shielded Twisted Pair Cable

It has same attenuation as unshielded
twisted pair. But it is faster than
unshielded and coaxial cable. It is more
expensive than coaxial and unshielded
twisted pair.
Shielded Twisted Pair Cable

Are you familiar
with Coaxial
Cable?
Transmission Media

What is Coaxial
Cable?
Transmission Media

Introduction to Networks and Programming Language

Coaxial Cable
Coaxial is called by this name because it contains
two conductors that are parallel to each other.
Copper is used in this as center conductor which
can be a solid wire or a standard one. It is
surrounded by PVC installation, a sheath which
is encased in an outer conductor of metal foil.
Transmission Media

Coaxial Cable
Outer metallic wrapping is used as a shield
against noise and as the second conductor
which completes the circuit. The outer
conductor is also encased in an insulating
sheath. The outermost part is the plastic cover
which protects the whole cable.
Transmission Media

Parts of Coaxial Cable
Transmission Media

Fiber Optic Cable
A fiber-optic cable is made of glass or
plastic and transmits signals in the form of
light.
Transmission Media

Fiber Optic Cable
Light travels in a straight line as long as it is
mobbing through a single uniform substance.
If ray of light travelling through one substance
suddenly enters another substance (of a
different density), the ray changes direction.
Transmission Media

Fiber Optic Cable
 Optical fibers use reflection to guide light
through a channel. A glass or plastic core is
surrounded by a cladding of less dense glass or
plastic.
Transmission Media

Fiber Optic Cable
 The difference in density of the two materials
must be such that a beam of light moving
through the core is reflected off the cladding
instead of being refracted into it.
Transmission Media

Internal view of an Optical
fiber
Transmission Media

Fiber Optic Cable Connectors
Transmission Media

The Subscriber Channel
(SC) connector is used for cable TV.
Transmission Media

The Straight-Tip (ST) connector is used
for connecting cable to the networking
devices.
Transmission Media

MT-RJ (Mechanical Transfer
Registered Jack) is a connector that is
the same size as RJ45.
Transmission Media

Part II
Overview of the Java Programming Language
Java Eclipse GUI
Hello World

Java
W I T H E C L I P S E A S A N I D E
PROGRAMMING

What is Java?
Java is built on C++ for a simple-to-use
language
 Java is a computer programming language. It enables
programmers to write computer instructions using
English-based commands instead of having to write in
numeric codes. It’s known as a high-level language because
it can be read and written easily by humans.

What is Java?
Like English, Java has a set of rules that
determine how the instructions are
written. These rules are known as its
syntax. Once a program has been written,
the high-level instructions are translated
into numeric codes that computers can
understand and execute.

Who Created Java?
In the early 90s, Java, which originally
went by the name Oak and then Green,
was created by a team led by James
Gosling for Sun Microsystems, a
company now owned by Oracle.

Who Created Java?
Java was originally designed for use on digital
mobile devices, such as cellphones. However,
when Java 1.0 was released to the public in
1996, its main focus had shifted to use on the
internet, providing interactivity with users by
giving developers a way to produce animated
web pages.

Who Created Java?
However, there have been many updates since
version 1.0, like J2SE 1.3 in 2000, J2SE 5.0 in
2004, Java SE 8 in 2014, and Java SE 10 in
2018.
Over the years, Java has evolved as a successful
language for use both on and off the internet.

Why Choose Java?
Java was designed with a few key principles in mind:
 Ease of Use: The fundamentals of Java came from
a programming language called C++. Although C++ is a
powerful language, it is complex in its syntax and
inadequate for some of Java's requirements. Java built on
and improved the ideas of C++ to provide a programming
language that was powerful and simple to use.

Why Choose Java?
 Reliability: Java needed to reduce the likelihood of
fatal errors from programmer mistakes. With this in
mind, object-oriented programming was
introduced. When data and its manipulation were
packaged together in one place, Java was robust.

Why Choose Java?
 Security: Because Java was originally targeting
mobile devices that would be exchanging data over
networks, it was built to include a high level of
security. Java is probably the most secure
programming language to date.

Why Choose Java?
 Platform Independence: Programs need to work
regardless of the machines they're being executed
on. Java was written to be a portable and cross-
platform language that doesn't care about the
operating system, hardware, or devices that it's
running on.

Using Java Comments
All Programming Languages Support Comments
Which are Ignored by the Compiler
 Java comments are notes in a Java code file that are
ignored by the compiler and runtime engine. They are used
to annotate the code in order to clarify its design and
purpose. You can add an unlimited number of comments
to a Java file, but there are some "best practices" to follow
when using comments.

Using Java Comments
 Generally, code comments are "implementation"
comments that explain the source code, such as
descriptions of classes, interfaces, methods, and fields.
These are usually a couple of lines written above or beside
Java code to clarify what it does.

Using Java Comments
 Another type of Java comment is a Javadoc comment.
Javadoc comments differ slightly in syntax from
implementation comments and are used by the program
javadoc.exe to generate Java HTML documentation.

Question…
Why Use Java
Comments?

Why Use Java Comments?
It's good practice to get into the habit of
putting Java comments into your source code
to enhance its readability and clarity for
yourself and other programmers. It isn't
always instantly clear what a section of Java
code is performing. A few explanatory lines can
drastically reduce the amount of time it takes
to understand the code.

Question…
Do They Affect How The
Program Runs?

Do They Affect How The Program Runs?
Implementation comments in Java code are
only there for humans to read. Java compilers
don't care about them and when compiling the
program, they just skip over them. The size
and efficiency of your compiled program will
not be affected by the number of comments in
your source code.

Implementation Comments
Implementation comments come in two different formats:
1. Line Comments: For a one line comment, type "//" and
follow the two forward slashes with your comment.
For example:
// this is a single line comment

When the compiler comes across the two
forward slashes, it knows that everything
to the right of them is to be considered as a
comment. This is useful when debugging a
piece of code.

Implementation comments come in two different
formats:
2. Block Comments: To start a block comment,
type "/*". Everything between the forward slash and
asterisk, even if it's on a different line, is treated as
a comment until the characters "*/" end the
comment.

For example:
/* this
* is
* a
* block
* comment
*/

Example Code with comment
/*This is my first program in java
* Another line here
*/
public static void main(String[] args)
{
System.out.println ("Hello World!");
}

4 Tips for Using Comments
1. Don't over comment. Every line of
your program does not need to be
explained. If your program flows
logically and nothing unexpected
occurs, don't feel the need to add a
comment.

2. Indent your comments. If the
line of code you are commenting is
indented, make sure your comment
matches the indentation.

3. Keep comments relevant. Some
programmers are excellent at modifying
code, but for some reason forget to
update the comments. If a comment no
longer applies, then either modify or
remove it.

4. Don't nest block comments. The
following will result in a compiler error:

Java Is Case Sensitive
Case Sensitivity in Programming
Languages is Common
Java is a case-sensitive language, which means
that the upper or lower case of letters in your
Java programs matter.

About Case Sensitivity
 Case sensitivity enforces capital or lower case in
text. For example, suppose you have created three
variables called "endLoop", "Endloop", and
"EndLoop". Even though these variables are
composed of the exact same letters in the same exact
order, Java does not consider them equal. It will
treat them all differently.

About Case Sensitivity
 This behavior has its roots in the programming
language C and C++, on which Java was based, but
not all programming languages enforce case
sensitivity. Those that do not include Fortran,
COBOL, Pascal and most BASIC languages.

What are the types of Java?
Data types in Java are classified into two types:
 Primitive—which include Integer, Character, Boolean, and
Floating Point.
 Non-primitive—which include Classes, Interfaces, and
Arrays.

Arithmetic Operator
+ Addition
- Subtraction
* Multiplication
/ Division
% Modulus
++ Increment
- - Decrement
+ = Addition assignment

Arithmetic Operator
- = Subtraction
assignment
* = Multiplication
assignment

Relational Operator
== Equal to
!= Not equal to
> Greater than
< Less than
>= Greater than or equal
to
<= Less than or equal to

Print Hello World in the
Console

Print Hello World in the Console
/* This program will printout Hello World
in the console */
public static void main(String[] args)
{
System.out.println ("Hello World!"); // this syntax is
use in printing text to console
}

Wrapping UP
 In this lesson you learned about,
Computer Networks
Coaxial Cable

Wrapping UP
 In this lesson you learned about,
JAVA programming
Java Eclipse GUI
Hello World

Introduction to Networks and Programming Language

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