Chapter 4- Software Basics- The Ghost in the Machine

Keep in mind: Open source means that a source is open to the public. You can also change the code behind this software or system.

Objectives:

• Three fundamental categories of software and relationships
• The relationship of algorithm to software
• Know the factors that make a computer application
• Know how file systems are organized and etc.

Linus Torvalds and the Software Nobody Owns

• Linus Torvalds- the Linux creator
• Linux= open source software
• Linux powers web servers, handhelds, scientific supercomputers.

*user interface-->application or other program-->operating system

Major categories of software:

1. compilers and other translator programs- lets programmers create different software (Ex: Intel compilers, Lahey compilers)
2. software applicators- help computer users solve problems in regards to productivity (Ex: Open Office)
3. system software-  coordinates hardware operations. Does the "behind-the-scenes" work a user rarely sees. (Ex: Microsoft Windows, Linux)

What are compilers? Computer programs that transform a source code written in a programming language into a computer language.

Processing with Programs
Note: The hardware in a computer system is equipped to produce whatever output a user requests.
For example: recipe = input out put= when u mix it and have your product

A fast, Stupid Machine

• Programmers begin with algorithms ( step-by-step instructions written in natural language (e.g. English))
• The steps are often over-achieving
• The steps are then translated into the vocabulary of a programming language

The Language of Computers

• Machine Language= numeric codes that represent data (ex.
• High-level language= a balance btween machine language and natural human language (ex.
• Natural Languages= resembles languages spoken by humans