Introduction to information systems T. Cornford, M. Shaikh is1 060 2013

4.5 Application software
Reading activity
Read Chapter 5 of Laudon and Laudon (2013) and Chapter 3 of Curtis and Cobham 
(2008).
All programs, including operating systems, need to be written before they 
can be run. In general, the programming languages in which programs 
are written are chosen because they make it easy for 
people
to express 
what they wish to achieve. Computers cannot directly understand such 
a language or execute the program. It is necessary therefore to translate 
from the language that a program is written in (say Java or C++), to 
the language that the computer understands (machine code). This task is 
undertaken by language translator programs: 
compilers
translate the 
entire program, producing a new version of the program – the object code; 
interpreters
translate and execute one statement of the source program 
at a time.
4.5.1 System development tools
Writing programs in modern programming languages, such as C++ or 
Java, provides great flexibility in what can be done and supports efficiency 
in the delivered product. It does not, however, support great productivity 
in the actual writing of programs. It has become increasingly common, 

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IS1060 Introduction to information systems
58
therefore, for all types of computer application to be written using 
tools that provide more help to the developer and need less detail to be 
specified. Good examples of this are the many database packages on the 
market, or spreadsheets. These provide, as you should discover doing your 
project work, an easy route to setting up storage of data and also provide 
tools to allow the design of input screens, models, output reports and the 
logic of processing information. A database package will provide some of 
the flexibility of a programming language, but also high-speed and pre-
packaged solutions to standard problems. Examples would be the way a 
spreadsheet provides sorting facilities or a database package the ability to 
generate reports.
Programming for the web is a rather different activity to conventional 
programming, and has given rise to many new tools, languages and 
techniques. Many development tools are now available for developing 
web-based systems quickly; these usually generate hypertext mark-
up language (HTML) 
−
the language for web pages 
−
but add newer 
techniques, such as extensible mark-up language (XML) and provide 
support for links to databases.