XAMPP, Instant Server Software

XAMPP is a software bundle containing:
- Apache -- Web server
- MySQL -- Database server
- PHP
- Perl

It also contains other several tools, phpMyAdmin, for example.

It is very convenient because you can download only one file,
extract it and it's ready to use.

You can extract it to a flashdrive too.
In this case, you can run services from the flashdrive directly. Cool!

Look, if you are a student.
When you're at school, you use a computer in the computer lab.
When you're at home, you use your computer in your bed room.
etc.

But you can carry your web app work and run it from any computer
without installing any software!