1. Software: Instructions to the Computer
A computer program is a series of instructions to a computer to execute any and all processes
Computers only “understand” instructions consisting of electrical signals alternating between two states

2. Software: Instructions to the Computer (Cont.)
Application software enables users to complete a particular task, such as word processing
System software enables application software to run on a computer and manages the interaction between hardware devices

3. Programming Languages
Abbreviated forms of instructions that translate into machine language
New programming languages make programming easier for people who are not necessarily hardware experts

4. Application Software vs. System Software
Program developed to address a specific business need; software for development of such programs
System:
Programs designed to carry out general routine operations, such as loading, copying, or deleting a file

5. Programming Languages (Cont.)

6. Bugs Errors in a program to be eliminated before it runs smoothly
Occur when a certain operation cannot be carried out
Logic errors are most difficult to spot

7. Application Software Application-specific programs
Programs designed to perform specific jobs
General-purpose programs
Usable for different purposes

8. System Software
Manages computer resources and performs routine tasks not specific to any application
Copying and pasting sections and files
Printing documents
Allocating memory
Developed to partner with application software

9. Operating Systems (O/S)
Most important system software
Developed for a certain microprocessor or microprocessors
Addresses technical details such as registers and RAM addresses
Plays the role of “traffic cop” or the “boss” of computer resources

10. Operating Systems (O/S) (Cont.)

11. System Software

12. Operating System Functions
Systems Management
User Interface
Memory Allocation
Multitasking, Multiprogramming, and Multiprocessing
Times and Statistics
Increasing Services from O/Ss

13. Popular Operating Systems

14. Linux and the Open Source Revolution
Proprietary software: source code of the software public
Open source software: source code can be obtained free of charge
Contains fewer bugs because thousands of independent programmers review the code
Required Reading:
Chapter 1 and 2 from “Understanding Open Source Software Development” by Joseph Feller and Brian Fitzgerald
Boole Q Fell

15. What is Open Source Software?
The term open source in common usage refers to any software with publicly available source code.
Open source software is required to have its source code freely available; end-users have the right to modify and redistribute the software, as well as the right to package and sell the software
Software with source code in the public domain meets the criteria, as does any software distributed under the popular GNU (GPL). Open-Source licences may have additional restrictions, such as a requirement to preserve the author’s names and copyright statement in the code.

16. What is Open Source Software?
Open Source can be either systems software (Linux) or application software (Mozilla, OpenOffice)
Growing in popularity
Linux now has 23% market share
Second only to Microsoft

17. Open Source Vs Proprietary
The “source” in “open source” refers to the program code or instructions on which software is based.
This is freely available for inspection unlike proprietary software e.g. MS Windows which is compiled into an executable form which runs on a computer.
Once the source is freely available, the software becomes free to the end user, since anyone can install it, compile it and then use it.

18. Open Source Organisation
the basic idea behind open source is very simple
When programmers can read, redistribute, and modify the source code for a piece of software, the software evolves.
People improve it, people adapt it, people fix bugs.
And this can happen at a speed that, if one is used to the slowpace of conventional software development, seems astonishing.
The open source community believes that this rapid evolutionary process produces better software than the traditional closed model, in which only a few programmers can see the source and everybody else must blindly use an opaque bloc of bits

19. Linux Developed by Linus Torvalds
Posted code on the internet and invited other developers to improve it.
Tens of thousands of developers have worked on it (Open Source Community).
Has been adopted by end-users and by established hardware vendors such as IBM and HP which supply it as an option with their computers.

20. Open Source Projects
Collaborative developments between software writers
Worldwide workforce of enthusiasts
Surprisingly, the software developed is stable enough to be used by commercial organisations

21. Case: OSS in Munich
May the city of Munich decided to oust Microsoft Windows from the 14,000 computers used by local-government employees in favour of Linux, an open-source operating system.
Although the contract was worth a modest $35m, Microsoft's chief executive, Steve Ballmer, interrupted his holiday in Switzerland to visit Munich and lobby the mayor.
Microsoft even dropped its prices to match Linux
a remarkable feat since Linux is essentially free and users merely purchase support services alongside it.
Microsoft still lost
The city did not wish to place the functioning of government in the hands of a commercial vendor with proprietary standards which is accountable to shareholders rather than to citizens.

22. Case: OSS in Munich
Modern governments generate a vast number of digital files.
From birth certificates and tax returns to criminal DNA records, the documents must be retrievable in perpetuity.
So governments are reluctant to store official records in the proprietary formats of commercial-software vendors. This concern will only increase as e-government services, such as filing a tax return or applying for a driving licence online, gain momentum.
In Microsoft's case, security flaws in its software, such as those exploited by the recent Blaster and SoBig viruses, are also a cause of increasing concern.

23. Case: OSS in Munich
Government purchases of software totalled almost $17 billion globally in 2002, and the figure is expected to grow by about 9% a year for the next five years.
Microsoft controls a relatively small part of this market, with sales to governments estimated at around $2.8 billion.
It is a crucial market, because when a government opts for a particular technology, the citizens and businesses that deal with it often have to fall into line. (In one notable example, America's defence department adopted the internet protocol as its networking standard, forcing contractors to use it, which in turn created a large market for internet-compliant products.)

24. Case: Ernie Ball Guitar String manufacturer
In 2000, the Business Software Alliance conducted a raid and audit on the firm
Found a few dozen unlicensed copies of programs
Settled for $65K + $35k in legal fees
BSA “named and shamed” the firm on the evening news and newspaper ads

25. Case: Ernie Ball
Ball told his IT department he wanted Microsoft products out of his business within six months
“I don't care if we have to buy 10,000 abacuses. We won't do business with someone who treats us poorly."
Ball's IT crew settled on open-source software
Red Hat's version of Linux
the OpenOffice office suite
Mozilla's Web browser
plus a few proprietary applications that couldn't be duplicated by open source.
Interview available at

26. Advantages: Proprietary Software
Indemnification;
Maintenance and support;
Licensee doesn’t have to have open source savvy staff;
Licensees’ rights if:
media is defective;
software contains viruses, backdoors, etc.;
product fails to meet written technical/business specifications.

27. Disadvantages: Proprietary Software
COST!
License fee
Product bundling—example: Microsoft office.
Licensee cannot modify or enhance the code;
Often not built to open standards, leading to interoperability problems;
Shut off from continuing development and information sharing in open source community;
Some proprietary code is not as good as its open source counterparts.

28. Advantages of Open Source
Effectively free to purchase (but cost of migration from existing systems may be high)
Lower cost of maintenance since software upgrades are free
Increased flexibility

29. Arguments against Open Source
Has less functionality than commercial software (but commercial software has a lot of functionality that is not used by end-users e.g. Office Assistant)
More likely to contain bugs since it is not tested commercially
Evidence suggests this is not the case
Poor quality of support
Although IBM, RedHat etc. do support Linux for a fee