User manual

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Fig. 1.5: ... or like that.
How much free space is on the memory card?
Not only hard drives of personal computers are quickly full - with the memory card of the Raspberry Pi
this happens much faster. That is why it is important to always keep an eye on the free and the used
space on the memory card. The status bar of the File Manager at the bottom on the right shows the
memory card’s free and used space.
1.4 The first program using Python
The programming language Python is preinstalled on the Raspberry Pi to help you getting started with
programming. Python impresses with its clear structure that offers an easy entry point to programming, but it
is also the ideal language to “quickly" automate the things you would otherwise do manually. Programming
is really fun, because you don’t have to observe variable declarations, types, classes or any complicated
rules.
Python 2.7.3 or 3.3.0?
The Raspberry Pi comes with two preinstalled versions of Python. Unfortunately, the latest version of
Python 3.x uses a partially different syntax than the proven version 2.x, so that the programs written in
one version do not run with the other. Some important libraries, such as the famous PyGame for the
programming of games and graphic display outputs are usually not available for Python 3.x. Because of
this and also because most of the available programs on the Internet are written for Python 2.x, for the
purpose of this book we are going to use the proven version Python 2.7.3. Our examples will work equally
on a Raspberry Pi with an older Python 2.x version installed.