Chapter 3 Using your Raspberry Pi^51THE OFFICIAL RASPBERRY PI BEGINNER’S GUIDE
GPIO, which lets you use the Pi’s GPIO pins – about which you’ll learn more in Chapter 6,
Physical computing with Scratch and Python – from another computer on your network.
Click on the Performance tab to see the third category. Here you can set the amount of
memory used by the Pi’s graphics processing unit (GPU) and, for some models, increase the
performance of the Raspberry Pi through a process known as overclocking. As before, though,
it’s best to leave these settings alone unless you know you need to change them.
Finally, click on the Localisation tab to see the last category. Here you can change your
locale, which controls things like the language used in Raspbian and how numbers are
displayed, change the time zone, change the keyboard layout, and set your country for WiFi
purposes. For now, though, just click on Cancel to close the tool without making any changes.
Shutting down
Now you’ve explored the Raspbian desktop, it’s time to learn a very important skill: safely
shutting your Raspberry Pi down. Like any computer, the Raspberry Pi keeps the files you’re
working on in volatile memory – memory which is emptied when the system is switched off.
For documents you’re creating, it’s enough to save each in turn – which takes the file from
volatile memory to non-volatile memory, the microSD card – to ensure you don’t lose anything.
The documents you’re working on aren’t the only files open, though. Raspbian itself keeps
a number of files open while it’s running, and pulling the power cable from the Raspberry Pi
while these are still open can result in the operating system becoming corrupt and needing to
be reinstalled.
To prevent this from happening, you need to make sure you tell Raspbian to save all its
files and make itself ready for being powered off – a process known as shutting down the
operating system.
WARNING!
Different countries have different rules about what frequencies
a WiFi radio can use. Setting the WiFi country in the Raspberry
Pi Configuration Tool to a different country from the one you’re
actually in is likely to make it struggle to connect to your networks
and can even be illegal under radio licensing laws – so don’t do it!WARNING!
Never pull the power cable from a Raspberry Pi without
shutting it down first. Doing so is likely to corrupt the
operating system and could also lose any files you have
created or downloaded.