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Unit -1

Introduction ToOpen Source Soft wares

&their configuration

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Client side scripting vs. Server side scripting

Client side scripting Server side scripting

Client side scripting is a script, that is

executed by the browser (i.e. Firefox,

Internet Explorer, Safari, Opera, etc.)

that resides at the user computer.

Server side scripting, is executed by

the server (Web Server like IIS,

apache), and the page that is sent to

the browser is produced by the serve-

side scripting

Client side scripting cannot be used to

connect to the databases on the web

server.

Server side scripting is used to

connect to the databases that reside on

the web server.

Response from a client-side script is

faster as compared to a server-sidescript because the scripts are

processed on the local computer.

Response from a server-side script is

slower as compared to a client-sidescript because the scripts are

processed on the remote computer.

Examples of Client side scripting

languages :JavaScript, VB script, etc.

Examples of Server side scripting

languages : PHP, JSP, ASP, ASP. Net,

Ruby, Perl n many more.

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Server side Scripting

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Overview of an OSS• It is computer software that is available in source

code form.

• By using an open source license the copyrightholders are provide all the rights to study, change,improve and to distribute the software.

•

Widely used open source products. – Linux Kernel (Operating System)

– Apache (Web Server)

– MySQL (Database emphasizing speed)

–

Postgre SQL (Database emphasizing functionality) – PHP(Server-side scripting)

– Filezilla (fast & reliable FTP client)

– Mozilla’s Firefox (Web Browser)

– Pant.net(Free image editing software)

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Open Source vs. Closed Source

•

Open source software – It can be defined as software distributed under a

licensing agreement, which allows the source code(computer code) to be shared, viewed and modified

by other users and organizations. – i.e. :- Linux , PHP , Mozilla’s Firefox

• Closed source software

– It can be defined as proprietary software distributedunder a licensing agreement to authorized users with

private modification, copying and republishing.

– i.e. :- Windows , ASP. Net , Google’s Chrome

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Cont…

Term Open Source Closed Source

Cost •Open source software may be

free. If you have in-house

capability for implementation,

training then it is the best option.

•The cost of proprietary software

will vary from a few thousand to a

few hundred thousand dollars,

depending on the complexity of the

system required.

Innovation Open source software enables

innovation by providing users

with the freedom and flexibility to

adapt the software , without

restriction.

Proprietary software providers do

not allow users to view or alter the

source code.

Usability No availability of the proper

documentation of the system is

available so its Requires system

administration expertise.

So it is developer-centric.

Proprietary software generally

employs expert usability testing, so

user provide proper documentation

for system.

So it is User- centric

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Advantages of Open Source• Larger Developer Support: As its open source anyone can develop for the

platform, giving it a much larger support for developers and gives them more of a

feeling of ownership as they can alter whatever they like.

• Customizable – In a closed source scenario, developers are given only options to

change what the original developer chooses, but having full control lets them

customize the look feel and even features of the software giving it much more

possibilities

• More Secure – Open source is much more transparent than closed, this means that

anyone can look over the code, by having thousands of people reading through your

code, bugs and vulnerabilities(weakness) are located much quicker and submitted

for fixing, it also lets you know if the bug has been fixed as you can check the code

after each release.

• Extended Community Support – As a product ages the original developer might

move on and stop developing leaving the product to age with no new fixes or

features, but if its open then usually the community takes over and continues

working on it allowing the usable life of the product to be extended well beyond

what the original developer intended.

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Advantages of Closed Source

• Less confusion for customers – Many people aren’t sure what

the advantages of the different versions of android, is HTCSense better than MotoBlur? By not allowing people to alter

core features it makes it easier to pick the product you want,

there is only one version of iOS that people need to learn about

• Unified experience – Because its close the developer canchoose the layout, the features, the options, the colors, and

pretty much anything they choose. This seems restrictive, but

at least guarantees that every user will have a similar

experience and gives it a standard that can’t be changed.• More profitable – A closed model can be greatly profitable as

you can charge money for developers to use your API, and can

lock out competition by not making your design available for

them to see.

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Development Philosophy

• According to “The Cathedral and Bazaar Model” the

Open Source Software are being developed whichhas following pattern:

– Users should be treated as co-developers

•

Users should have access to source code• Users are encouraged to submit code fixes for the s/w and also

report bugs and documentation.

• Linux’s law says : ” Given enough eyeballs all bugs are shallow.”

• Many users view same source code then they find all bugs and

ways to solve them.

– High modularization

• The general structure of the software should be modular allowing

for parallel development on independent components.

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Cont…

– Frequent Integration

• Code changes should be integrated as frequently as possible to avoid integration at the end of the project life-

cycle.

– Several versions

• There should be at least 2 versions of software:-

1. Development version with more no. of features.

2. Stable version with fewer no. of features.

• Development version should be used by the developer

willing to take risk of the code which is still not developedcompletely and want to use the latest features. Such user

can act as a co-developer and help in reporting bugs as well

as providing fixes to those bugs.

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Free Software

• Free source software

– It is just small software which are free, It can be

downloaded ,used ,copied without restrictions

– but their codes are not accessible.

• Free soft wares are soft wares made by the

company, and distributed free for use.

– Such as Internet Explorer or MSN Messenger, YahooMessenger...stuff like that.

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Open Source vs. Free Source• Open source means that the source code is available

to all users, and they are free to use, modify, and re-distribute the source code.

• Open source soft wares are also free but thedifference is that –

open source soft wares can be edited and can be updated by anyone who wants and knows who to program in thesource code.

– Good examples are Linux, Unix. So basically the coresource code is provided to anyone by the company

directly, – where as the free soft wares mostly do not provide their

source code to the people who want to program in it.

– Examples are Internet Explorer or MSN Messenger,Yahoo Messenger, etc…

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Shareware Software

• Shareware software’s are used for marketing purpose.

• Computer users can download and use a limited

version of software or full version of softwarefor a limited period of time.

• We can say that Shareware software is just like

“Try before you buy”.• Example: Snagit.

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Source Available

•

Source available is software where the source isavailable for viewing, but which may not legally be

modified or redistributed.

• Such software is more often referred to as source-

available, or as shared source.

• In response to the demands of its customers for

access to source code, Microsoft created its shared

source licensing program.

• This program allows Microsoft customers to read

and examine certain of the company’s source code.

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Distribution term of OSS

•

Free Redistribute – License shall not restrict any part from selling or

giving the s/w as a component of an aggregate s/w

distribution containing programs from several

different sources.

• Source Code

– Program must include source code , you also allow

to distribute it as source code as well as in acompiled form

– The source code must be the preferred form in which

the programmer could modify.

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Cont…

• Derived Works

– License must allow modification and derived works

– It should allow them to be distributed under the

same terms as the license of original software.

• Distribution of license – Rights attached to program must apply to all to

whom the program is redistributed without the needs

for execution of additional license.

• License must not be specific to a product

– Rights attached to program must not depend on

programmer being part of particular s/w distribution

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Pros for Developers

• From a developer’s point of view, open sourcetechnologies provide a platform on which to build custom solutions.

• Rather than develop, say, an entire proprietary

operating system, developers can build andimprove upon the already existing open sourceLinux operating system platform.

• In this way, more time is spent on the specifictask to be solved rather than getting the systemup and running to the point where it is stableand reliable.

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Cons of OSS for Developers

• Unfortunately, this means that other developers

have access to the developer’s work and can

easily create a competing product.

• Almost everything in open source is viewable

by other developers. If a developer makes a

major mistake, it can become public

information and discolor the developer’s reputation.

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Cons for Users • However, one problem using open source

technology is that the focus is often on backend

processing of information and not on user

interfaces.

• Microsoft Windows has arguably one of the easiestinterfaces with which to work.

• Often, open source software such as Linux requires

the user to have specialized knowledge that cannot be configured with just clicks of a mouse.

• All open source projects do not have good

documentation to walk the user through the learning

and usin of the technolo ies.

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Open source technology importance

•Open source software is software that includessource code and is usually available at no charge.

• There are additional requirements besides theavailability of source code that a program must

meet before it is considered open sourceincluding: – the software must be free to redistribute;

– derivative works must be allowed;

–

the license can not discriminate against any persons;• Software that is licensed under an open source

license allows for a community of developersfrom around the world to improve the software by providing enhancements and bug fixes.

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Cont… • Open source software is generally available for free and

it is not necessary to purchase additional licenses forevery computer that the program is to be installed on orfor every person who is going to use the software.

• Open source software not only has a lower acquisition

cost than proprietary software, it often has lowerimplementation and support costs as well.

• It is easier to evaluate open source software then proprietary software.

•Since open source software is typically freely available todownload, librarians and systems administrators caninstall complete production-ready versions of softwareand evaluate competing packages.

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Documents

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