Information Systems Development
This chapter focuses on the concepts surrounding the development of information systems. It begins with a discussion of software development methodologies, then covers programming languages and tools, and finishes with a review of implementation methodologies. As you read, reflect upon all the different pieces that must come together in order for a system to be developed.
Compiled vs. Interpreted
Besides identifying a programming language based on its generation, we can also classify it through the distinction of whether it is compiled or interpreted. A computer language is written in a human-readable form. In a compiled language the program code is translated into a machine-readable form called an executable that can be run on the hardware. Some well-known compiled languages include C, C++, and COBOL.
Interpreted languages require a runtime program to be installed in order to execute. Each time the user wants to run the software the runtime program must interpret the program code line by line, then run it. Interpreted languages are generally easier to work with but also are slower and require more system resources. Examples of popular interpreted languages include BASIC, PHP, PERL, and Python. The web languages of HTML and JavaScript are also considered interpreted because they require a browser in order to run.
The Java programming language is an interesting exception to this classification, as it is actually a hybrid of the two. A program written in Java is partially compiled to create a program that can be understood by the Java Virtual Machine (JVM). Each type of operating system has its own JVM which must be installed before any program can be executed. The JVM approach allows a single Java program to run on many different types of operating systems.