Chapter 4: Software Basics: The Ghost in the Machine

Open Source-open to the public.

Non-open source- not open to the public.

Linus Torvalds and the Software Nobody Knows

• Linus Torvalds- a genius
  
• Created the Linux


• It is the best known example of open source software


• It powers Web servers, film and animation workstations, scientific supercomputers, and a handful of handhelds.


• Open source software: open for the public and it is reliable because of constant updates.


• means you can change the code behind the system or software.


• Three major categories of software:


• Compliers and other tranlator programs: enable programmers to create othe rsoftware.


• sees the syntax of your code if it's right or wrong.


• Example: Intel compliers like translator


• Software applications: serve as productivity tools to help computer users solve problems.


• Example: Microsoft Word like product


• System software : coordinates hardware operations and does behind-the-scenes work the computer user seldom sees.
  

Processing with Programs

• Food for thought


• The hardware in acomputer system is equipped to produce whatever output a user requests.


• Example: iIf you have a recipe for french toast- that is your input, then if you mix the ingreidients all together then- your result is the output.


• Set of rules to solve a pro


• A fast, stupid machine


• Programmers begin with an algorithm: a set of step-by-step instructions written in a natural languafe,e.g,English


• The steps are cpmplicated, long and error pone


• The steps are translated into the vocabulary

Sofware Applications: Tools for Users

• Consumer Applications


• Many software companies have replaced their printed documentation.


• Tutorials


• Reference Materials


• Help files


• On-line help


• Upgrading: Users can upgrade a program to the new version by paying an upgrade fee the the software manufacturer.


• Ex:Itunes


• Newer releases often have additional features and fewer bugs-an error.


• Compatibility


• It allows to function properly with the hardware, operating system, and peripherals.


• Programs written for one type of computer system may not work on another.


• Ex:Macintosh and Intel


• Disclaimers


• Software manufacturers limit their liability for software problems by selling software "as is"


• Created whether you like it or not; don't use it.


• Licensing: Commercial software is copyrightes so it can't be legally duplicated for distribution.


• Software license


• Volume license


• Distribution: Software is distributed via:


• Direct sale


• Retail stores


• Mail-order catalogs


• Web sites


• Not all software is copyrighted.


• Public domain software


• Shareware- search to make sure software isn't copyrighted.


• Web applications


• Web applications fall into several categories:


• Some simple Web applications perform simple data-processing tasks that could also be performed by traditional programs running on stand-alone PCs.


• Ex: Flashplayer,etc....


• Most Web applications take advantage of the Web's strength as a huge repository


• of information.


• Ex: pictures and outside info


• Many Web applications leverage the Web's strength as a huge repository of information.


• Some Web applications support online business transactions.


• News-oriented Web applications provide up-to-the minute reports on a myriad(countless)of subjects.


• Other Web applications support a more traditional form of information broadcasting.