Software includes the operating systems such as W95/W98/Me/NT/W2K/XP/W2K3/Vista/Linux/OS9/OSX, word processor, spreadsheets, browsers, email programs, newsreaders, compilers, validators, backup programs, device drivers, utilities and games.

There are several types of software:

open source

Anyone with sufficient computer programming skills can look at how the program works, and create their own variations.

freeware

The program is free, but you are not permitted to modify it or peek inside to see how it works.

shareware

You are allowed to use the program, but if you use it regularly you are expected to pay a small fee. Sometimes doing so unlocks extra features.

trialware

You are allowed to use the program free for a while to test it out, typically a week to 90 days, then it stops working unless you pay and fee and register.

shrink wrap

The program comes in a pretty box and you usually buy it in a retail store. If you don’t like it, if it unsuitable or if it does not work you can’t take it back since they presume you made a copy of the CDs inside.