Open Source Open Source SoftwareSoftware

An Introduction

The Creation of SoftwareThe Creation of Software

As you know, programmers create the software that we use

What you may not understand is HOW software is created

Machine LanguageMachine Language

Computer programs (software) are basically sets of instructions that the computer follows

Computers don’t take instructions in English (or anything close to it!) Instead, they follow instructions which are written

in BINARY Basically, instructions are given by specifying them

BY NUMBER

Known as Machine Language You can’t understand it, but the machine can!

Programming LanguagesProgramming Languages

Programmers don’t typically work in machine language Too hard to understand, work productively

Rather, they use high-level Programming Languages to create their programs These are sets of instructions which are much

closer to the language that WE use Easier to understand, to use Examples: C, C++, Java, Perl, Python, (Visual) Basic, etc.

Compiling and Source CodeCompiling and Source Code

Because computers only understand ML, the original program (in the high-level language) must be CONVERTED to ML The conversion is known as ‘Compiling’ We often call the resulting ML code an

‘Executable’ file The original program, as written by

the programmer in the high-level language, is known as Source Code It’s the ‘Source’ of the program

Source Code- Key pointsSource Code- Key points

Source Code Understood by humans Can’t be executed by computer Can be translated into machine language

Executable (machine language) Can be executed Can’t be understood easily Can’t be translated into source code

When you buy software…When you buy software…

What do you get? Source code or executable?

Why?

If You Have the Source Code, You If You Have the Source Code, You can:can:

Understand how the software works internally Use this knowledge to develop other software

Make changes Bug fixes Customize

Make sure there are no bugs, security flaws, etc.

Improve on the software

So, why don’t software companies (usually) give you source code?

Open Source SoftwareOpen Source Software

Current movement had (has) a philosophical basis:

Software should be FREE Not just free as in ‘free beer’

No cost Free as in ‘free speech’

Access to ideas, knowledge Freedom of expression The more heads that you have working on a

problem, the better the result When knowledge is restricted to a small few, society

is hurt When knowledge is shared freely, everyone benefits

Open Source SoftwareOpen Source Software

Open Source Software is FREE Variety of license agreements Best known is the GPL

It can be distributed for free Although a company can charge for it, they can’t

prevent you from distributing it for free You must have access to the source code!

GrowthGrowth

OSS has grown dramatically recently Availability of software Quality of software ADOPTION of software

QuestionsQuestions

Where does Open Source Software come from? Who makes it? Why?

Answers…Answers…

Many sources Programmers devoting personal time

Outside working hours Companies developing OSS as a tool in the

other services they offer Companies developing software internally,

then releasing it free of charge Contributions by public institutions,

educational institutions Investment by various parties funding

development

QuestionsQuestions

Is the software any good?

Answers…Answers…

In many cases, YES! Much OSS is very useful, well developed

OpenOffice Mozilla Linux

In some areas, it is dominant! Apache web server MySQL for web database use BIND DNS server

QuestionsQuestions

Why are companies/governments/ individuals moving to OSS?

AnswersAnswers

Sick of unreasonable licensing terms Getting worse!

Don’t want to be locked into one company’s system OSS typically relies on open standards

Ability to customize software Can inspect code to ensure that it is

secure Significant cost savings

QuestionsQuestions

Are there companies making money using Open Source Software?

If so, what is the business model for these companies? What do they make/do? How do they make money? Are these viable business models?

How are they doing?

QuestionsQuestions

What are the implications of Open Source Software for ‘closed source’ companies?

How can ‘closed source’ companies fight the threat?

As a Network Administrator…As a Network Administrator…

Why might you want to use OSS?

Why might you be hesitant?

QuestionsQuestions

If OSS is so great, why would I ever used closed source software?

Why stick with ‘Closed Source’?Why stick with ‘Closed Source’?

Belief that corporate developed software is better

Need for support Concerns about learning curve is change made

Some OSS software not nearly as easy to use There may not be an OSS package available to

do a particular task Or, may not be as strong as the closed source

option

ConclusionConclusion

Why selecting software, you need to consider the situation carefully Look at the needs, and make the best

choice

Open Source Software is a good alternative in many situations Don’t assume it’s bad, because it’s free!