Open-Source Software Project Development Instructor: Dr. T.Y. Wong Week

8/14/2019 Open-Source Software Project Development Instructor: Dr. T.Y. Wong Week

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Instructor: Dr. T.Y. Wong

Open-Source Software Project Development

Week 1, Part 1

Introduction to

Open-Source Development


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Spring semester2008-2009

CSC4140 Open-SourceSoftware Project Development

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Why do we need a license?

The fundamental purpose of a license,

e.g., license on a book, is to: protect the originality of the work;

protect the inventors right;

the deny anybody the right to exclusivelyexploit the work.

Free software license and Open-source

license do different things.


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What is a free software?Free software isas in free speech,not in free beer.

How to interpret the CODE?

Speech itself does not carryany monetary value. But, theaction may take value.

E.g., Clintons speech takesseveral millions HKD. But, the

speech itself may be

Beer itself has monetaryvalue. But, you may beable to get it for free.


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What is a free software?Free software isas in free speech,not in free beer.

Stallmans Utopia

The price tag on the software shouldbe removed. Programmers should giveit out free-of-charge.

I make a living by giving outfree software. In return, Ireceive donations. It isgreat. Why not joining us?

Source: http://www.gnu.org/software/global/model.html


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A free software license?Free software isas in free speech,not in free beer.

The license says: any

users can free touse, study, copy, modify,

and redistribute the

computer software

GNU Public License - GPL


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A free software license?Free, but withone and only onerestriction

The license also says: A user is free to modify the code.

When the user distributes themodified software, the new

software is automatically carriesGPL.

GNU Public License - GPL


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A free software license?

Stallmans action was to initially opposeUNIX because there is a price tag on UNIX.

He was so sad about commercialsoftware: you own the physical copy of

the software, but you are bound not to copy the work; not to make derivative works based on the

work; and

not to authorize anyone else to do either ofthe above two things.

Have you ever heard of the EULA, end-

user license agreement?

Software shouldbe free!!


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What is an open-source software?



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Open-source software == free software?

Not exactly.

Depends on which license the software bears.

GPL LGPL MozillaDerived work carries thesame license.

MIT BSD ApacheDerived work may be allowedto go close-source!

Derived work may not carrythe same license, but have to

reflect originality of the work.

Qt Artistic CC


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Open-Source Software Development Cycle



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Traditional softwaredevelopment cycle:

Programmers work in the office.

They have regular meetings to

brainstorm ideas, scolded bybosses, etc.

They have the manager tocheck on their progress.


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Open-source softwaredevelopment cycle:

Office? Yes, programmers usuallyhave a regular job. However, theywork on the open-source software

at home.

Meeting? Yes, but on the Internet.

Manager? Yes, instead, he/she iscalled the lead programmer(s) orthe project founder(s).


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They need to communicate in order thatthey all know the progress and havediscussion.

Before the age of ICQ, they use IRC &

mailing lists.

Taiwan

England

IndiaIRC, mailing list.

Programmers are usually located in

different geographical locations.

U.S.


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They need tools to manage the sourcecodes in a way that distributedprogrammers can access and update.

E.g., git and subversion (svn).

Taiwan

England

Indiagit, svn, cvs

Programmers are usually located in

different geographical locations.

U.S.


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Pros and Cons of Open-Source

Pros #1: innovation.

There are great people who:

Dont ask for any reward;

Just want to contribute to the world;

Make the (computer) world a better place;

E.g., Linus Torvalds wrote his Intel-based Minix-likekernel just because he wanted to contribute to the

community.


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Pros #2: reliability.

There are large number of people who:

are interested in existing open-source projects; and

are willing to devote time to make the projects better;

Such a number is too big comparing to commercialsoftware companies

because every (enabled) user can help to fix bugs since the

software is open-source. Close-source software cannot entertain from such a benefit.


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Pros #3: longevity.

A commercial software may be abandoned byits publisher.

E.g., Microsoft Corp. wants to discontinue the

Windows XP in order to boost the adoption rate ofWindows Vista.

Not the case for open-source. RedHat VS Fedora.


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Cons #1: lack of support Suppose you bought the MS Windows Server

2008 and its license. When you encounter any problems

a phone call to Microsoft can help you.

Suppose you downloaded the Ubuntu 8.10.

When you encounter any problems Ask the doc, Ask the expert, or Askgoogle are the only ways out (not a phone call toDr. Wong).


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Cons #2: Licensing problems

Open-source software with GPL is problematic to

commercial companies. E.g., I think that software A, which is under GPL, is great,

but it is not great enough.

Then, I modify it and it is perfect now. Can I sell the new software A and make a profit?

Yesbut, you have to open the source Then, everyone knows how you implement it.

Then, why does someone need to pay?


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Brief open-source software history



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The DotCom Era

Apache

1995

(Not drawn to scale)

JavaScript

PostgreSQL

IBM adopted

open-sourcesoftware

Netscape issuedGPL version

1998 2000


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Brief open-source software history



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The DotCom bubble bursted

Open-source software become more mature. Many companies started their business based

on open-source software.

Release both proprietaryand open-source versions.

targets onenterprise users.


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Trends in Open-Source Software



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Our course will focus on

how to develop robust and efficient server software.

how to use the web browser as an ubiquitous,versatile interface to ugly programs.

Server software Apache (Web), MySQL (database), Samba(Windows file sharing), etc.

Interface for CLI,non-user-friendlysoftware

GNOME vs Console, phpMyadmin vs mysql-client,SWAT vs text editor, etc.

Open-Source Software Project Development Instructor: Dr. T.Y. Wong Week

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