Archive for the ‘Linux’ Category

Download WaryPy.vdi for VirtualBox

15/04/2012

A few people have commented saying that they have tried to run RacyPy in VirtualBox and run into problems with PAE.

I’ve made a .vdi based of “WaryPy”. No PAE required.

WaryPy.vdi

MD5 sum:

15297a83b87bac54f58667f25820f076

 

Java

16/03/2012

The version of the Java Development Kit you have installed in RacyPy2 is 1.7.0_02.

Firstly, I’d like to recommend Herbert Schildt’s books. I am using “Java: The Complete Reference”.

You can download the (free) first chapter of his “Java: A Beginner’s Guide” from various places online.

I am not going to write a lot about Java here – it’s better if you read the Schildt chapter. But I will mention that in Java, all programs use the Object Orientated programming model. We will get around to using this approach in Python (it’s very useful and amazingly powerful). But for simple programs, we haven’t really needed to use it.

What this means in practice is that every Java program has at least one “class”. Here’s an example:

The first four lines are a multi-line comment – we use /* to start these and */ to close them.

Next we have the command that declares the main “class”  of the program. It’s essential that this has the same name as the name of the file. It’s traditional to give this class an initial capital letter. Java is case-sensitive. So if i have called my file “Hello.java”, my class has to be called “Hello” (not “hello”). The curly braces “{” are used to group a block of code – here the contents of this class.

The next line is a single-line comment which we do by starting the line with “//”.

The next line is one you will see in almost all Java programs (I think – I am only a learner!). I’m not entirely sure what each of the commands means yet! But the important thing is that this line include the call to “main()” which all Java programs need. The next curly brace opens a new code-block – this time for what our program will actually do. What this line actually does is to invoke a class called “System” which gives us control of things like output to the screen. Within this class there is a method called “out” which does just that – outputs to the screen. The “println()” bit is just like print() in Python3 – it will print what we put inside the brackets – in this case a string enclosed in quotation marks – and add a newline. The line ends with a semi-colon because all “statements” in Java must end with a semi-colon. The lines that don’t end in semi-colons are not actually “statements” (yes – I found this a bit confusing at first, but you’ll get the hang of it!).

Then we close the curly braces that enclose the “main()” part of our code, and finally close the curly braces that end the description of our class “Hello”.

Anyway, the fun bit comes next! We have to compile our program!

Open a terminal in the directory where you saved “Hello.java”. Then type:

javac Hello.java

This compiles your program into Java bytecode. You then issue the command:

java Hello

And your program should run.

Just to make this really clear, I’ve done a few extra commands here. Typing “pwd” displays the directory we are in. Then “ls” lists the files in it. As you can see, there’s just the file “Hello,java”. Once we have run “javac Hello.java” a new file is created: “Hello.class”. When we type: “java Hello”, Java looks for a class called “Hello” and executes it, printing: “Hello World!”.

Wow, are you having fun yet!

antiloquax

Extra stuff for RacyPy2

15/03/2012

PETS

Pets are easily installed packages for Puppy Linux. Just click the link and choose open with PetGet.

Enjoy!

Scratch-1.4


Lua-5.2.0


Ruby-1.9.3

I don’t know a huge amount  about Lua and Ruby, but these websites should get you started.

Lua

Ruby

 

If you are using RacyPy and need some help with general Puppy Linux stuff, the forum here is great.

antiloquax

While you wait for your Raspberry Pi, why not use RacyPy2?

03/03/2012

How to use RacyPy or WaryPy.

1. Download the .iso.

2. Download and install DVD Decrypter (or use you favourite .iso burning software).

3. Right click on the .iso file and choose “Burn with DVD Decrypter.

4. Reboot your PC. It should boot from the CD, if it doesn’t do this by default, look for a message telling you what to press for boot options (often F2 or F9).

5. That’s it.

 

To run WaryPy in Virtual Box.

1. Download WaryPy.vdi.

2. Download and install VirtualBox.

3. Start VirtualBox. Choose “new”.

4. Follow the instructions on screen and choose “Linux” and Linux 2.6.

5. Choose “use existing hard disk” and find the .vdi file.

6. Start your new virtual machine.

 

Since Liz posted on the RPi homepage about this LiveCD, I’ve had a lot of hits on the blog. Quite a few people have asked about running Puppy in VirtualBox. This works really nicely and I have uploaded a .vdi file for WaryPy (this seems to be better for VB as it doesn’t need PAE).

The .iso of RacyPy is  here.

This Operating System is aimed at people with no experience of using Linux. If you are excited about the Raspberry Pi and keen to start learning to program, this could be useful to you.

Features:

1. The original version only came with Python 3 and Pygame. This one has Python 2.7.2 and 3.1.4. Both have Pygame installed which means you are ready to start learning to code whichever version you favour.

2. On the old version I had added a lot of tutorials for several programming languages. This time I have decided to keep it simple. There are lots of great materials for learning Python (you’ll find them in an archive file in my-documents). I’ve left out the others, becuase I am sure that those who want to try other programming languages will have no difficulty finding them.

3. I have included the Java Development Kit (1.7.2). This means that if you wan to learn Java too, you can compile and run Java code without needing to install anything.

4. Typing tutorial included. The nice “gtypist” program is installed, because good coding requires typing skills!

As before, there’s no need to install anything – you just put the disc in your optical drive and boot from it. You can save your work to a memory stick or onto the hard drive without doing anything at all to your existing operating system. If you want to install it, there’s lots of help on the Puppy forum.

As before, this OS is based on Racy Puppy. Racy has a very up-to-date Linux kernel. But it’s a lightweight distribution that should run nicely on quite old machines (eg it’s fine on my old Toshiba laptop with a Pentium 3 processor and 256mb of RAM). If there’s an old computer in your house that no-one uses any more, you will probably find that RacyPy runs really well on it. So you can use this system while we wait for our RPis to be delivered!

happy coding

antiloquax.

BugFix (if you haven’t got the latest version).

You may notice that Java isn’t working in Seamonkey. To fix it, click on this link and choose open with petget. I put the wrong link in the plugins folder – oops!

Why should I try Puppy Linux?

03/03/2012

I am not going to try to convince you to give up on Windows or Mac Operating Systems, I just wanted to do a post about my favourite Linux distribution: Puppy Linux.

Here are some of the reasons why it is worth learning how to use Linux.

1. The Raspberry Pi will come with a Linux operating system (I think the closest thing to the RPi version is probably this: Fedora Spin LXDE). Since a lot of us may be waiting a while for our Raspberry Pis, why not get used to using Linux while you are waiting?

Tux

2. Linux is Open Source. You don’t have to pay for a Linux operating system. You don’t have to pay if you want to upgrade to a newer version. You don’t have to bother with licences, security keys, activation and so on. You are in control of what happens on your machine. Also we have this lovely mascot, Tux!

3. Linux is much less vulnerable to viruses.

4. Linux file-systems don’t fragment as much as Windows – so you don’t need to defragment your hard-drive.

5. Linux systems usually run faster than Windows. This may not be the case if you go for one of the big distributions (like Ubuntu), but if you use a lightweight version (like Puppy), you will find your machine boots and operates much faster.

6. Linux systems can bring old computers back to life. Becuase they are smaller and faster, you can put Linux distros on a machine that couldn’t cope with Windows 7 and find that you can still do all the things you want to do.

7. You can use Linux to rescue your system. If your Windows machine won’t boot and you can’t fix it (or can’t wait for someone else to) you can still get at all your files. Just boot from a Linux live cd and you can access your data and put it somewhere safe.

8. Linux is easy to use. Some people will tell you that you have to be some kind of computer genius to use Linux. This is not the case. You can use a Linux system and make it work perfectly just by using the point-and-click approach. You don’t need to go near the command line unless you want to …

9. Linux has a massive online community of well-informed, helpful, users. I would guess that every Linux distribution has its own forum. People on there will be happy to help you if you do have any problems. For instance, this is the forum for Puppy users.

Well, I hope that you will give Linux a try. In case you missed it, you can find Puppy Linux here.

Or, if you prefer, you can try my remix of Racy Puppy – set up especially for Raspberry Pi fans.

antiloquax

Introducing RacyPy

16/02/2012

I am very proud to announce the birth of “RacyPy”. This is a bootable Linux Operating System with Python 3.1.4 and Pygame built in (it’s based on Racy Puppy).

You can download the .iso from here. Edit – better to get the new version – here.

Once you’ve done that, you’ll need to burn the .iso to a cd, using your favourite burning utility.

Then, you can reboot the computer. Many PCs will automatically check for a bootable CD before looking at the hard-drive, but you might have to hit a key to make the computer boot from the CD.

RacyPy will run in RAM and doesn’t do anything to your hard-drive, unless you choose to install it. When you shutdown for the first time, it will ask you to create a save file. You can have this on the hard-drive or somewhere else (eg a memory stick – you’ll need about 512Mb of space).

When you are running RacyPy, you will notice a little snake icon on the desktop. Clicking this will launch the Python IDLE. If you look in “my-documents” you’ll find tutorials for Python and other programming languages.

I hope you will give it a try – it will be a great introduction to working in Linux, as well as helping you to start coding as soon as possible.

The iso is here.

There are additional packages and some discussion over on the Murga Linux forum.

Happy Coding!

antiloquax