OS - Phidget SBC: Difference between revisions

Revision as of 17:40, 14 March 2018

Quick Downloads

Already know what you're doing? Here you go:

For PhidgetSBC (1070):

For PhidgetSBC2 (1072):

For PhidgetSBC3 (1073) kernel version 3.6.3:

For PhidgetSBC3 (1073) kernel version 3.14.27:

For PhidgetSBC4 (SBC3003):

Getting Started With the Phidget SBC

Welcome to using the Phidget SBC. If you haven't already, check out the user guide in order to set up the following:

Networking
Administrator password

If you are ready to go, the first step will be deciding how you will use the SBC:

Use the SBC like any other Linux computer, simply connect a monitor and a keyboard and begin your development.
Use a more powerful external computer to develop your code, and then simply copy the files to the SBC.

If you are using an external computer, there are videos available to help you get started, here is a video for Java:

We also have videos for Python and C.

If you will not be using an external computer, jump ahead to learn about installing packages for development, otherwise, keep reading!

Developing with an External Computer

There are two main ways in which you can access your SBC from an external computer:

SBC Web Interface
Secure Shell (SSH)

The user guide covers the SBC Web Interface in detail, so we will review SSH below.

SSH

If you are unfamiliar with SSH, it is a simple yet powerful tool that allows you to log into a remote machine in order to execute commands. You can also transfer files using the associated SCP tool.

In order to use SSH, you need to know the following things about the SBC:

IP address (e.g. 192.168.3.195) or the link local address (e.g. phidgetsbc.local)
The administrator password

You must also enable SSH on the SBC. You can do this via the SBC Web Interface which is shown in the image below:

SSH on Windows

To use SSH on Windows, we recommend PuTTY. Use the images below as a guide for configuring PuTTY (use the IP address or the link local address interchangeably):

After clicking open, simply login as root and provide the administrator password:

To transfer files between your SBC and Windows machine, we recommend either of these programs:

You will follow a similar process to access the SBC as described for SSH.

SSH on Linux and macOS

SSH is available on Linux and macOS by default. To run SSH, simply open the terminal and type the following:

ssh root@phidgetsbc.local

Or, something like this (you will need to know the IP address of your SBC):

ssh root@192.168.3.195

You will then be prompted for the password in order to gain access to the SBC:

To copy a file from the SBC to your development machine using SCP, simply open the terminal and type the following:

scp root@phidgetsbc.local:/path/to/source /path/to/destination

You can reverse this if you want to transfer a file from your development machine to your SBC:

scp  /path/to/source root@phidgetsbc.local:/path/to/destination

Installing Packages for Development

At this point you have connected to the SBC through one or more these three options:

SBC Web Interface
SSH
Directly via monitor and keyboard

Now that you are connected, you may want to start developing on/for the SBC. Before you do this, you need to install some packages. Let's start with C and Java.

C and Java

The simplest way to install C and Java support on the SBC is via the install buttons on located on the SBC Web Interface (System->Packages). Check Include full Debian Package Repository before installing.

When developing for Java, ensure your development machine and your SBC have the same version of Java. Check your Java version by entering this command:

Java -version

If you need to update the version of Java on your SBC, use the following commands:

apt-get install openjdk-7-jre-headless
su
update-alternatives --config java

You're now ready to begin programming! Continue through this guide for code examples and directions on where to go next.

Installing Python

Installing support for Python has three steps:

Ensure Include full Debian Package Repository is checked on the SBC Web Interface (System->Packages)
Install Python
Install Phidget Python module

You will need to run commands on the SBC to install support for Python. You can either use SSH to issue the commands, or you can connect directly to the SBC via a monitor and keyboard.

Basic Python

The base Python functionality can be downloaded and installed in one step:

apt-get install python

Next, install the Phidget Python module.

Method 1: Use the Internet

First, install wget and unzip:

apt-get install wget
apt-get install unzip

Next, copy the web link address for the Python Libraries and use it in the following command (right click to copy into a terminal):

wget http://copied_link

The Phidget Python libraries should now be downloaded in the folder you ran the previous command in. The next step is to unzip the file:

unzip filename

Finally, change directories to the unzipped folder:

cd /path/to/unzipped/folder

and install the Phidget Python libraries:

python setup.py install

You're now ready to begin programming! Continue through this guide for code examples and directions on where to go next.

Method 2: Use a USB Key

Copy the Python Libraries onto a USB key. Unpack the zip file into a folder on the USB key. Insert the key into the SBC.

You will have to figure out where the USB key (and the Phidget Python library folder) is now located. We describe how in the general Using USB Data Keys section. Next, run the following commands (be sure to modify the usb directory number if necessary):

cd /media/usb0/
python setup.py install

You're now ready to begin programming! Continue through this guide for code examples and directions on where to go next.

Developing Applications

If you are interested in developing on an external computer, keep reading. If you are planning on developing directly on the SBC, you can jump ahead to developing directly on the SBC.

Developing with an External Computer

When developing on an external computer, you will write, compile, and test your programs on that machine. When you are ready, you will then upload your programs to the SBC to run them. To demonstrate, we will use the Hello World example for Java. Download the following on your development machine before we get started:

Next, follow these steps:

1. Place phidget22.jar on your development machine in a directory that you will use to compile your Java files.

2. Copy the HelloWorld.java file from the example package to the same directory.

3. Compile the HelloWorld.java file. If you are using a Windows machine, type the following into the command prompt:

javac -classpath .;phidget22.jar HelloWorldExample.java

If you are using a Linux or macOS machine, type the following into the terminal:

javac -classpath .:phidget22.jar HelloWorldExample.java

You should now have the following class file:

HelloWorldExample.class

4. Using the SBC Web Interface, create a new project called HelloWorld:

5. On the next screen, you will be prompted to upload your files. We will upload the Java class file, and then click the Start button:

6. You'll note that as it runs, there are two links below the Stop button:

stdout: view the program output like you would in a terminal or command prompt
stderr: view the program error output

Success! The HelloWorld example is running on your SBC. If you aren't interested in developing directly on the Phidget SBC, jump ahead to running a program automatically.

Developing Directly on the Phidget SBC

When developing directly on the SBC, you will do so in one of the following ways:

Access the terminal by connecting directly to the SBC using a keyboard and monitor.
Access the terminal by using SSH.

Regardless of how you choose to access the terminal, the process is the same. First, you will need to pick a terminal editor in order to write and edit your files. Here are some options we recommend:

nano - recommended for beginners, already installed
vi - advanced, already installed
emacs - advanced, needs to be installed

Next, follow these steps:

1. If you haven't already, connect to the SBC using SSH or a keyboard and monitor.

2. Download the Phidget Java HelloWorld Example to the SBC.

wget http://examples_link

3. Unpack the examples

unzip examples_filename

4. Compile the HelloWorldExample.java example:

javac -classpath .:/usr/share/java/phidget22.jar HelloWorldExample.java

5.Run the HelloWorldExampleprogram:

java -classpath .:/usr/share/java/phidget22.jar HelloWorldExample

Success! The HelloWorld example is running on your SBC. Now that you have a program running on your SBC, you may be interested in having it run automatically when the SBC boots, or maybe even on a schedule. Keep reading for more information.

Running a Program Automatically

After testing your program, you will likely want it to run on boot, or on a schedule, without your input.

Run on Boot

Running on boot ensures that your program will never miss an event. As long as the SBC is running, your code will be running. This section assumes you have written and compiled your program on an external computer, and have uploaded it to the SBC Web Interface. If you are not using the SBC Web Interface, jump ahead to using a boot script.

To have your program run on boot, navigate to Projects->ProjectName->Startup Settings in the SBC Web Interface. After selecting your project, copy the settings from the image below:

We will review some of the options that are shown in the image above:

Startup Order: lower numbers boot first. Booting later means more programs are available for use, booting earlier means other programs can use your program.
Run as a daemon: starts the program as a daemon. Unless you have explicitly written your program as a daemon, leave this checked, or else your SBC may hang on boot.
Executable/Class name: your main Java class or C file.
Arguments: any command line arguments the program needs.

After saving your changes, your program will run automatically whenever your SBC boots.

Run on a Schedule

Running your program on a schedule allows you to perform your task once a week, or once a minute without worrying about memory management issues or instability problems that may arise. It executes, and then gets cleaned up. To run your program on a schedule, we recommend using Cron. Cron can automatically schedule programs (known as jobs, or cron jobs). Cron simply reads a crontab file and runs whatever programs are listed, with whatever timing they are listed with. Cron runs continuously in the background, but the cron jobs only run as long as they naturally would, and then they exit.

Let`s set up your first cron job. We will use nano to edit the crontab file, but feel free to use whatever editor you prefer.

First, set your editor to nano:

export EDITOR=nano

Next, edit your crontab file:

crontab -e

Finally, schedule your cron job:

#cron job that will run at 5AM every week:
0 5 * * 1 /root/code/myprogram argument1

After entering your task, simply save and exit the file.

Run Using a Boot Script

If you want your program to run on boot, you can install your program into the boot order using a script. This process is covered here.

Programming

Ready to write some code? Select one of the programming languages below:

Phidget Network Server

The Phidget Network Server is an extremely useful feature of Phidgets that allows you to remotely control Phidgets over your network. If you haven't already, check out the Phidget Network Server page for a complete overview.

Try it Out!

The Phidget SBC comes with the Phidget Network Server installed, and the SBC automatically starts the Network Server on boot. In order to change any of this default behaviour, navigate to Phidgets->phidget22NetworkServer using the SBC Web Interface:

In order to try the Phidget Network Server out, you will need a host computer, and a client computer:

Host computer: the computer that is physically connected to the Phidgets via USB and is running the Phidget Network Server.
Client computer: a computer running a Phidgets application that accesses Phidgets connected to the host computer.

For this example, we will use the Phidget SBC as the host computer. The next step is setting up your client computer. If you are using a Windows computer as your client, keep reading, otherwise, you can jump ahead here:

macOS Client
Linux Client

Windows Client

In order to remotely access Phidgets on your SBC, you should get your client computer set up. Follow the Getting Started guide for Windows below before continuing:

Getting started with Windows

Now that you have Phidget drivers and libraries installed on your client computer, we can test the Phidget Network Server by following the steps below:

1. Open the Phidget Control Panel on your client computer. You will see something like this:

2. You now have access to the Phidgets that are connected to your Phidget SBC. Try double-clicking one of them to bring up an example.

macOS Client

In order to remotely access Phidgets on your SBC, you should get your client computer set up. Follow the Getting Started guide for macOS below before continuing:

Getting started with macOS

Now that you have Phidget drivers and libraries installed on your client computer, we can test the Phidget Network Server by following the steps below:

1. Open the Phidget Control Panel on your client computer. You will see something like this:

2. You now have access to the Phidgets that are connected to your Phidget SBC. Try double-clicking one of them to bring up an example.

Linux Client

In order to remotely access Phidgets on your SBC, you should get your client computer set up. Follow the Getting Started guide for Linux below before continuing:

Getting started with Linux

Now that you have Phidget drivers and libraries installed on your client computer, we can test the Phidget Network Server by following the steps below:

1. From the terminal, type in the following command:

 phidget22admin -s

You will now see something like this:

As shown in the image above, the server running on your SBC can now be seen over the network. You will now be able to remotely access any Phidgets connected to your SBC.

What's Next?

Now that you have seen the Network Server in action, you may be interested in implementing an application that takes advantage of all it's features. Luckily, every programming language we support comes with example code on how to do this! Jump to programming languages above.

Advanced Information

Writing Image to SD Card

If you would like to reflash your micro SD card, your first step will be to download the SBC4 SD Card Image. After downloading, unzip to get the .img file.

The next step is to flash your card. We recommend Etcher for flashing - this supports Windows, macOS, and Linux. It's also possible to flash from the command line on macOS and Linux, but this is not recommended as it does not verify the image (See Command Line).

Download and run Etcher. Plug in the MicroSD card using a card reader. Etcher will probably pick up the card automatically - otherwise, chose the card. Select the .img file using the select image button. :

Next, press the Flash! button. After writing and verifying, you will see:

The next step is to plug the SD card back into the SBC and expand the file system. Jump ahead to expanding your file system.

Command Line

NOTE: Flashing from command line is not recommended. Please consider using Etcher on Windows, macOS or Linux.

macOS

You should have already completed the first step, which is downloading the SD card image:

Next, make sure your SD card is plugged in, and enter the following into your terminal:

diskutil list

This will list all of the devices currently mounted on your system:

After verifying which device is your SD card, unmount it using the following command:

diskutil unmountDisk /dev/diskX

Warning: Ensure you are writing to the correct disk

Next, we can write the image file to the SD card:

if= path to your image file
of = where to write output (note using rdisk instead of disk will result in faster write times)

After writing, you are almost done. The next step is to plug the SD card back into the SBC and expand the file system. Jump ahead to expanding your file system.

Linux

You should have already completed the first step, which is downloading the SD card image:

Next, make sure your SD card is plugged in, and enter the following into your terminal:

dh -f

This will list all of the devices currently mounted on your system:

After verifying which device is your SD card, unmount it using the following command:

umount /dev/sdXX

Next, we can write the image file to the SD card:

if= path to your image file
of = where to write output (note: do not include partition number)

Warning: Ensure you are writing to the correct disk

After writing, you are almost done. The next step is to plug the SD card back into the SBC and expand the file system.

Expanding your File System

Note: PhidgetSBC4 SD card image version 3.0.0+ automatically expands the filesystem on first boot. For older SD card images, continue reading.

After writing the image file to your SD card, you will need to expand the file system size in order to take advantage of the full capacity of your card. In order to do this, you must run the expandfs.sh script which can be accessed at the / directory as shown here:

Note: if you plan on using SSH in order to run this script, you will need to enable SSH first (as it is turned off by default). Enabling SSH was covered above in the SSH section.

Next, simply run the script:

The SBC will automatically reboot, and your file system will be expanded. You can confirm that it has expanded by checking the file system size report.

Checking System Logs

The SBC maintains two logs: a kernel log and a system log.

The kernel log is for low-level occurrences, such as devices attaching and leaving the USB hub, recording what drivers are being used, and so on.

The system log (syslog) is for normal chatter from the operating system. Any program with the right permissions can use it (though you need to know the method to write to it, information all around the Internet can help) and it contains everything from the Ethernet going up and down, to webserver requests, and so on. If you don't run many programs or services on the SBC, the syslog will essentially be a mirror of the kernel log, because the kernel is the only thing talking.

You can check these logs by using the web interface in the System → Logs tab.

Or you can perform more powerful filtering and displaying via an SSH terminal. For example, dmesg is the command to display the kernel log, and tail prints the last ten lines of input. So, if you are trying to see if you can get a device to be detected on USB, you can run dmesg | tail to print the latest ten lines of kernel log data.

The actual locations of the log files (for filtering and reading) are:

/var/log/syslog
/var/log/dmesg

But don't edit them directly! Always follow the advice and procedures around the Internet on how to properly log items to syslog.

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OS - Phidget SBC: Difference between revisions

Revision as of 17:40, 14 March 2018

Contents

Quick Downloads

Getting Started With the Phidget SBC

Developing with an External Computer

SSH

SSH on Windows

SSH on Linux and macOS

Installing Packages for Development

C and Java

Installing Python

Basic Python

Method 1: Use the Internet

Method 2: Use a USB Key

Developing Applications

Developing with an External Computer

Developing Directly on the Phidget SBC

Running a Program Automatically

Run on Boot

Run on a Schedule

Run Using a Boot Script

Programming

Phidget Network Server

Try it Out!

Windows Client

macOS Client

Linux Client

What's Next?

Advanced Information

Writing Image to SD Card

Command Line

Expanding your File System

Checking System Logs

Further Reading

Navigation menu

@@ Line 1: / Line 1: @@
+<metadesc>Communicate with sensors, controllers and relays with the PhidgetSBC! It uses Debian Linux and can run autonomous programs in C, Java, and Python.</metadesc>
 [[Category:OS]]
 __TOC__
@@ Line 4: / Line 5: @@
 ==Quick Downloads==
 Already know what you're doing? Here you go:
-*[{{SERVER}}/downloads/phidgetsbc/SBC3003/linux-4.8.3/phidgetsbc4.bin PhidgetSBC4 Firmware]
-*[{{SERVER}}/downloads/phidgetsbc/SBC3003/linux-4.8.3/phidgetsbc4-kerneldev.tar.gz PhidgetSBC4 Kernel Development Package]
-*[{{SERVER}}/downloads/phidgetsbc/SBC3003/changelog changelog]
-Note: updates should normally be done via the System -> Packages page on your PhidgetSBC4 web interface. It is rarely necessary to completely re-flash your device.
+'''For PhidgetSBC (1070):'''
+*[{{SERVER}}/downloads/phidgetsbc/1070/changelog.txt changelog]
+*[{{SERVER}}/downloads/phidgetsbc/1070/phidgetsbc-minimal.bin Minimal Firmware]
+*[{{SERVER}}/downloads/phidgetsbc/1070/phidgetsbc-full.bin Full Firmware]
+*[{{SERVER}}/downloads/phidgetsbc/1070/buildroot-phidgetsbc.tar.gz Buildroot/Kernel Sources]
+'''For PhidgetSBC2 (1072):'''
+*[{{SERVER}}/downloads/phidgetsbc/1072/changelog.txt changelog]
+*[{{SERVER}}/downloads/phidgetsbc/1072/phidgetsbc2.bin SBC2 Firmware]
+*[{{SERVER}}/downloads/phidgetsbc/1072/phidgetsbc2-kerneldev.tar.gz SBC2 Kernel Development Package]
+'''For PhidgetSBC3 (1073) kernel version 3.6.3:'''
+*[{{SERVER}}/downloads/phidgetsbc/1073/changelog.txt changelog]
+*[{{SERVER}}/downloads/phidgetsbc/1073/linux-3.6.3/phidgetsbc3.bin SBC3 Firmware]
+*[{{SERVER}}/downloads/phidgetsbc/1073/linux-3.6.3/phidgetsbc3-kerneldev.tar.gz SBC3 Kernel Development Package]
+*[{{SERVER}}/downloads/phidgetsbc/1073/linux-3.6.3/phidgetsbc3-upgrade_3.6.3_3.14.27.tar.gz SBC3 Kernel upgrade package (3.6.3 -> 3.14.27)]
+'''For PhidgetSBC3 (1073) kernel version 3.14.27:'''
+*[{{SERVER}}/downloads/phidgetsbc/1073/changelog.txt changelog]
+*[{{SERVER}}/downloads/phidgetsbc/1073/linux-3.14.27/phidgetsbc3.bin SBC3 Firmware]
+*[{{SERVER}}/downloads/phidgetsbc/1073/linux-3.14.27/phidgetsbc3-update_3.14.27.tar.gz SBC3 Kernel update package (3.14.27)]
+*[{{SERVER}}/downloads/phidgetsbc/1073/linux-3.14.27/phidgetsbc3-kerneldev.tar.gz SBC3 Kernel Development Package]
+'''For PhidgetSBC4 (SBC3003):'''
+*[{{SERVER}}/downloads/phidgetsbc/SBC3003/changelog.txt changelog]
+*[{{SERVER}}/downloads/phidgetsbc/SBC3003/phidgetsbc4.zip SBC4 SD Card Image] | [{{SERVER}}/downloads/phidgetsbc/SBC3003/phidgetsbc4.md5 md5]
+*[{{SERVER}}/downloads/phidgetsbc/SBC3003/SBC3003_upgrade.tar.gz SBC4 Kernel/Bootloader Upgrade Package]
-==Getting Started with the Phidget SBC==
+==Getting Started With the Phidget SBC==
 Welcome to using the Phidget SBC. If you haven't already, check out the [[SBC3003 User Guide#Getting Started | user guide]] in order to set up the following:
 * Networking
@@ Line 21: / Line 41: @@
-'''Warning''': Regardless of how you decide to use the SBC, you will be running on the SBC as root (super-user). This means you are able to overwrite important system files without the system asking for additional permissions.
+If you are using an external computer, there are videos available to help you get started, here is a video for Java:
+<center>{{#ev:youtube|InbY-Ui1tg0}}</center>
+We also have videos for [https://www.youtube.com/watch?v=y7XhShmhiEU&list=PLwPK-C9lEEc0iciKTiWSWZ74tQysd2lsS&index=4 Python] and [https://www.youtube.com/watch?v=8vv8kx4743c&list=PLwPK-C9lEEc0iciKTiWSWZ74tQysd2lsS&index=2 C].
-If you will not be using an external computer, jump ahead to learn about [[#Installing packages for development|installing packages for development]], otherwise, keep reading!
-===Developing with an external computer===
+If you will not be using an external computer, jump ahead to learn about [[#Installing packages for development|installing packages for development]], otherwise, keep reading!
+===Developing with an External Computer===
 There are two main ways in which you can access your SBC from an external computer:
 *SBC Web Interface
@@ Line 37: / Line 60: @@
 In order to use SSH, you need to know the following things about the SBC:
-*IP address (e.g. 192.168.1.123) or the link local address (e.g. phidgetsbc.local)
+*IP address (e.g. 192.168.3.195) or the link local address (e.g. phidgetsbc.local)
 *The administrator password
@@ Line 62: / Line 85: @@
 SSH is available on Linux and macOS by default. To run SSH, simply open the terminal and type the following:
 <syntaxhighlight lang=bash>
-ssh root@phidgetsbc.locald
+ssh root@phidgetsbc.local
 </syntaxhighlight>
 Or, something like this (you will need to know the IP address of your SBC):
 <syntaxhighlight lang=bash>
-ssh root@168.254.3.0
+ssh root@192.168.3.195
 </syntaxhighlight>
@@ Line 82: / Line 105: @@
 </syntaxhighlight>
-===Installing packages for development===
+===Installing Packages for Development===
 At this point you have connected to the SBC through one or more these three options:
 *SBC Web Interface
@@ Line 88: / Line 111: @@
 *Directly via monitor and keyboard
-Now that you are connected, you may want to start developing on/for the SBC. Before you do this, you need to install some packages. Let's start with C/C++ and Java.
+Now that you are connected, you may want to start developing on/for the SBC. Before you do this, you need to install some packages. Let's start with C and Java.
-====C/C++ and Java====
+====C and Java====
-The simplest way to install C/C++ and Java support on the SBC is via the install buttons on located on the SBC Web Interface (System->Packages). Check ''Include full Debian Package Repository'' before installing.
+The simplest way to install C and Java support on the SBC is via the install buttons on located on the SBC Web Interface (System->Packages). Check ''Include full Debian Package Repository'' before installing.
@@ Line 112: / Line 135: @@
 ====Installing Python====
 Installing support for Python has three steps:
-*Ensure ''Include full Debian Package Repository'' is checked on the SBC Web Interface (System->Packages)
+#Ensure ''Include full Debian Package Repository'' is checked on the SBC Web Interface (System->Packages)
-*Install Python
+#Install Python
-*Install Phidget Python module
+#Install Phidget Python module
 You will need to run commands on the SBC to install support for Python. You can either use SSH to issue the commands, or you can connect directly to the SBC via a monitor and keyboard.
@@ Line 133: / Line 156: @@
 </syntaxhighlight>
-Next, copy the web link address for the [{{SERVER}}/downloads/libraries/PhidgetsPython.zip Python Libraries] and use it in the following command (right click to copy into a terminal):
+Next, copy the web link address for the [{{SERVER}}/downloads/phidget22/libraries/any/Phidget22Python.zip Python Libraries] and use it in the following command (right click to copy into a terminal):
 <syntaxhighlight lang=bash>
 wget http://copied_link
@@ Line 156: / Line 179: @@
 =====Method 2: Use a USB Key=====
-Copy the [{{SERVER}}/downloads/libraries/PhidgetsPython.zip Python Libraries] onto a USB key.  Unpack the zip file into a folder on the USB key.  Insert the key into the SBC.
+Copy the [{{SERVER}}/downloads/phidget22/libraries/any/Phidget22Python.zip Python Libraries] onto a USB key.  Unpack the zip file into a folder on the USB key.  Insert the key into the SBC.
 You will have to figure out where the USB key (and the Phidget Python library folder) is now located.  We describe how in the general [[#Using USB Data Keys | Using USB Data Keys]] section. Next, run the following commands (be sure to modify the usb directory number if necessary):
@@ Line 166: / Line 189: @@
 You're now ready to begin programming! Continue through this guide for code examples and directions on where to go next.
-==Programming with the Phidget SBC==
+==Developing Applications==
-===Writing a Phidget Program===
+If you are interested in developing on an external computer, keep reading. If you are planning on developing directly on the SBC, you can jump ahead to [[#Developing directly on the Phidget SBC | developing directly on the SBC]].
-There are three ways to write and upload a Phidget program:
+===Developing with an External Computer===
+When developing on an external computer, you will write, compile, and test your programs on that machine. When you are ready, you will then upload your programs to the SBC to run them. To demonstrate, we will use the Hello World example for Java. Download the following on your development machine before we get started:
+*[{{SERVER}}/downloads/phidget22/examples/java/Manager/Phidget22_HelloWorld_Java_Ex.zip Java HelloWorld Example]
+*[{{SERVER}}/downloads/phidget22/libraries/any/Phidget22Java.zip phidget22.jar]
-#Using the SBC Web Interface:
-#*This is useful for simple projects written in C or Java that you want to start at boot.
-#Using SSH or Using the SBC via keyboard and monitor
-#*Useful for projects that run at scheduled times (e.g. once per minute).
-#*Useful for projects that use languages other than Java or ARM-compiled C.
-#*Can also be used to start programs at boot, however, a startup script is needed. See [[OS - Linux#As A Service|this example]].
-If you aren't sure which method you prefer, keep reading. Otherwise, you can jump ahead here:
+Next, follow these steps:
-*Using SSH to run a program? Jump ahead to [[#Program with SSH|programming with SSH]].
-*Developing directly on the SBC? Jump ahead to [[#Developing Code on the SBC|developing code on the SBC]].
-*Using the Web Interface with your Java/C program? Keep reading!
-====Program in Java with the Web Interface====
+. Place phidget22.jar on your development machine in a directory that you will use to compile your Java files.
-To show how to write, compile, and install Java programs on the SBC, we'll use the Hello World example for Java. Download the [{{SERVER}}/downloads/examples/JavaJNI.zip Java example package] and make sure you have the same version of Java on both your development machine and on the SBC (how to check your version number was covered [[#Installing C/C++ and Java| above]]).
-The first step to getting the HelloWorld code running on on your SBC starts with your external development machine:
+. Copy the HelloWorld.java file from the example package to the same directory.
-#Download [{{SERVER}}/downloads/examples/phidget22.jar phidget22.jar]
-#Place the SBC version of phidget22.jar on your development machine in the directory that you will use to compile the Java files.
-#Copy the HelloWorld.java file into that working directory.
-#Compile the HelloWorld.java file from within that working directory. From the command line prompt on Windows, this will be:
-#:<syntaxhighlight lang=bash>
-javac -classpath .;phidget22.jar HelloWorld.java
-</syntaxhighlight>
-#:In a terminal on Linux or Mac OS, this will be:
-#:<syntaxhighlight lang=bash>
-javac -classpath .:phidget22.jar HelloWorld.java
-</syntaxhighlight>
-#You should now have three compiled class files:
-#*HelloWorld.class
-#*HelloWorld$1.class
-#*HelloWorld$2.class
-#Using the SBC Web Interface, create a new project called HelloWorld:
-#:[[File:sbc_create_project.png|link=|alt=|center]]
-#On the next screen, you will be prompted to upload your files. We will upload the three Java class files, and then click the Start button:
-#:[[File:sbc_web_run_project.png|link=|alt=|center]]
-#You'll note that as it runs, there are two links below the Stop button:
-#*stdout: view the program output like you would in a terminal or command prompt
-#*stderr: view the program error output
+. Compile the HelloWorld.java file. If you are using a Windows machine, type the following into the command prompt:
-Success! The HelloWorld example is running on your SBC. If you aren't interested in programming with SSH, or developing directly on the Phidget SBC, jump ahead to [[#Running a program automatically|running a program automatically]].
+<syntaxhighlight lang=bash>
+javac -classpath .;phidget22.jar HelloWorldExample.java
-====Program with SSH====
-To show how to write, compile, and install Java programs on the SBC, we'll use the Hello World example for Java. Make sure you have Java installed before starting (this was covered [[#Installing C/C++ and Java| above]]).
-#Connect to the SBC using SSH.
-#Download the [{{SERVER}}/downloads/examples/JavaJNI.zip Phidget Java Examples] to the SBC.
-#:<syntaxhighlight lang=bash>
-wget http://copied_link
 </syntaxhighlight>
-#Unpack the examples
+If you are using a Linux or macOS machine, type the following into the terminal:
-#:<syntaxhighlight lang=bash>
-unzip filename
-</syntaxhighlight>
-#phidget22.jar is located at:
-#:{{Code|/usr/share/java/phidget22.jar}}
-#Compile the HelloWorld.java example:
-#:<syntaxhighlight lang=bash>
-javac -classpath .:/usr/share/java/phidget22.jar HelloWorld.java
-</syntaxhighlight>
-#To run the HelloWorld program, use:
-#:<syntaxhighlight lang=bash>
-java -classpath .:/usr/share/java/phidget22.jar HelloWorld
-</syntaxhighlight>
-Success! The HelloWorld example is running on your SBC. If you aren't interested in developing directly on the Phidget SBC, jump ahead to [[#Running a program automatically|running a program automatically]].
-====Developing Code on the SBC====
-When you're developing directly on the SBC, you will need to use a terminal editor:
-*nano - ''recommended for beginners''
-*vi
-*emacs - ''needs to be installed''
-To install emacs, run this command on the SBC (ensure ''Include full Debian Package Repository'' is checked on the SBC Web Interface in System->Packages):
 <syntaxhighlight lang=bash>
-apt-get install emacs
+javac -classpath .:phidget22.jar HelloWorldExample.java
 </syntaxhighlight>
-Other than creating/editing files directly on the terminal, your experience will be identical to someone using SSH, so if you haven't read the section directly above, do so now.
+You should now have the following class file:
+*HelloWorldExample.class
-===Running a Program Automatically===
-After testing your program, you will likely want it to run on boot, or on a schedule, without your input.
-Running on boot:
+. Using the SBC Web Interface, create a new project called HelloWorld:
-*Never miss an event. As long as the SBC is running, your code will be running.
-Running on a schedule:
-*Perform your task once a week, or once a minute without worrying about memory management issues or instability problems that may arise. It executes, and then gets cleaned up.
-If you have made your choice and want to run your program on a schedule, jump ahead to [[#Run on a schedule| running on a schedule]]. Otherwise, keep reading to learn how to run on boot!
+[[File:Phidgetsbc_createproject.PNG|link=|alt=|center]]
-====Run on boot====
-This section deals with programs written in either Java or ARM-compiled C. If you are using a different type of program, jump ahead to [[#Via a Boot Script|using a boot script]].
-To have your program run on boot, navigate to Projects->Startup Settings in the SBC Web Interface. After selecting your project, copy the settings from the image below:
+. On the next screen, you will be prompted to upload your files. We will upload the Java class file, and then click the Start button:
-[[File:phidgetsbc_runonstartup.PNG|link=|alt=|center|826x755px]]
+[[File:Phidgetsbc_runprogram.PNG|link=|alt=|center]]
-We will review some of the options that are shown in the image above:
+. You'll note that as it runs, there are two links below the Stop button:
-*Startup Order: lower numbers boot first. Booting later means more programs are available for use, booting earlier means other programs can use your program.
+*stdout: view the program output like you would in a terminal or command prompt
-*Run as a daemon: starts the program as a daemon. Unless you have explicitly written your program as a daemon, leave this checked, or else your SBC may hang on boot.
+*stderr: view the program error output
-*Executable/Class name: your main Java class or C file
-*Arguments: any command line arguments the program needs
-'''Warning:''' Ensure your program is stable before taking the above steps. A program that is unstable (i.e. has memory leaks or similar) will cause your SBC to crash after running for days, or months on end.
-====Run on a schedule====
+Success! The HelloWorld example is running on your SBC. If you aren't interested in developing directly on the Phidget SBC, jump ahead to [[#Running a program automatically|running a program automatically]].
-To run your program on a schedule, we recommend using Cron. Cron can automatically schedule programs (known as ''jobs'', or ''cron jobs''). Cron simply reads a ''crontab file'' and runs whatever programs are listed, with whatever timing they are listed with. Cron runs continuously in the background, but the cron jobs only run as long as they naturally would, and then they exit.
+===Developing Directly on the Phidget SBC===
+When developing directly on the SBC, you will do so in one of the following ways:
+*Access the terminal by connecting directly to the SBC using a keyboard and monitor.
+*Access the terminal by using SSH.
-Let`s set up your first cron job. We will use nano to edit the crontab file, but feel free to use whatever editor you prefer!
+Regardless of how you choose to access the terminal, the process is the same. First, you will need to pick a terminal editor in order to write and edit your files. Here are some options we recommend:
+*nano - ''recommended for beginners, already installed''
+*vi  - ''advanced, already installed''
+*emacs - ''advanced, needs to be installed''
-#Set your editor to nano:
-#:<syntaxhighlight lang=bash>
-export EDITOR=nano
-</syntaxhighlight>
-#Edit your crontab file:
-#:<syntaxhighlight lang=bash>
-crontab -e
-</syntaxhighlight>
-#Schedule your cron job
-#:<syntaxhighlight lang=text>
-minute hour dayOfMonth month dayOfWeek  YOUR_COMMAND
-</syntaxhighlight>
-Done! Here is an example of a cron job that will run at 5 AM every week:
+Next, follow these steps:
-<syntaxhighlight lang=text>
-5 * * 1 /root/code/myprogram argument1
-</syntaxhighlight>
-====Run using a boot script====
-If you want your program to run on boot, you can install your program into the boot order using a script. This process is covered [[OS - Linux#As A Service|here]].
-===Programming Languages===
-Ready to write some code? Select one of the programming languages below:
-*[[Language - C/C++|C/C++]]
-*[[Language - Java | Java]]
-*[[Language - Python | Python]]
-*[[Language - JavaScript | JavaScript]]
-*[[Language - C_Sharp | C#]] - ''not recommended, but possible using Mono''
-==Network Server==
-The SBC comes with the [[Phidget Network Server]] installed, and the SBC automatically starts the Network Server at boot.
-To practice using the Network Server, and to learn more about it, check out [[OS - Linux#Using the Network Server|the Network Server section]] of the Linux page.
-==Advanced Information==
-===Shutting off USB ports to save power===
-The SBC3 has an on-board USB hub that can control power to the ports. To do this unbind and rebind the USB drivers.
-To turn off the ports {{code|echo "1-1" >/sys/bus/usb/drivers/usb/unbind}}
-To turn on the ports {{code|echo "1-1" >/sys/bus/usb/drivers/usb/bind}}
-These will also cause detach and attach events for the Phidget devices, respectively. While the drivers are unbound, you will not get any hot plug events for any devices on USB.
-===Using a Touchscreen===
-Please note that this will ONLY work with an SBC3 since it has a USB 2.0 hub:
-Using a touchscreen with the SBC is a great way to get user input and visual feedback from an SBC otherwise devoid of visual output.  The SBC does not have any conventional display ports such as VGA, DVI, or HDMI but it does have a number of USB ports and USB displays do exist.  With the upgrade to a USB 2.0 hub on the SBC3 from the earlier models which had USB 1 hubs the SBC now has enough capability to operate a screen over USB.  We don't recommend running a standard desktop environment since the processor is too slow to really keep up with a typical desktop it does make for an excellent interface for a kiosk, instrumentation control panel or  other, similar use case.  This document is going to go through the process of enabling support for a typical USB display as well as installing a fairly compact desktop environment called xfce on the SBC.
-The screen I will be using is from a company called [http://lilliputweb.net/ Lilliput].  Specifically a UM-70 model.  Before you begin, please make sure that you have the screen plugged into the SBC, it will also be useful to have a spare USB keyboard and mouse handy as you will need them once you are no longer using an SSH terminal to communicate with the SBC.
-[[File:lilliputoff.jpg|center|400px|link=]]
-====Getting the display to function====
-Begin by logging into the web configuration page for your SBC and upgrading all of the packages on the SBC.  Be sure to include the full Debian package repository.  For more information on how to do this refer to the  [[OS - Phidget SBC#Getting Started - External Computer|getting started]] section of the Phidget SBC documentation.  Once you are fully up to date open an SSH session with the SBC and navigate to the "/etc" folder.  Open inittab with a terminal-based text editor such as nano and add the following to the bottom of the file, just above the {{code|T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100}} line:
+. If you haven't already, connect to the SBC using SSH or a keyboard and monitor.
-<div class="source">
+. Download the [{{SERVER}}/downloads/phidget22/examples/java/Manager/Phidget22_HelloWorld_Java_Ex.zip Phidget Java HelloWorld Example] to the SBC.
 <syntaxhighlight lang=bash>
-:2345:respawn:/sbin/getty 38400 tty1
+wget http://examples_link
-:23:respawn:/sbin/getty 38400 tty2
-:23:respawn:/sbin/getty 38400 tty3
-:23:respawn:/sbin/getty 38400 tty4
-:23:respawn:/sbin/getty 38400 tty5
-:23:respawn:/sbin/getty 38400 tty6
 </syntaxhighlight>
-</div>
-Now reboot your system.  After a few minutes you should see the LCD screen come up with a standard Linux terminal interface and a login prompt.  This is all well and good but this isn't really appreciably better than simply using an SSH session to communicate with the SBC.
-[[File:lilliputlogin.jpg|center|400px|link=]]
-====Setting up Xfce====
-In order to get a traditional windowing environment we still need to install a desktop manager as well as a number of supporting packages.  Log in and make sure everything is still up to date with:
-<div class="source">
+. Unpack the examples
 <syntaxhighlight lang=bash>
-apt-get update
+unzip examples_filename
 </syntaxhighlight>
-</div>
-Then install the following packages:
+. Compile the HelloWorldExample.java example:
-<div class="source">
 <syntaxhighlight lang=bash>
-apt-get install xserver-xorg lxde xfce4
+javac -classpath .:/usr/share/java/phidget22.jar HelloWorldExample.java
 </syntaxhighlight>
-</div>
-If the SBC asks you if you want to continue, just type "Y" and press enter.
+.Run the HelloWorldExampleprogram:
-This will install the xfce desktop environment and any other necessary programs on the SBC.  When it's done, restart the SBC.  When it boots back up it should boot directly to a login screen instead of the terminal interface.  Log in, and you are good to go.  It won't be particularly fast, but don't worry, the SBC does not have a dedicated video processor on it so it's perfectly normal for it to be slow.  What's important is that it works.
-[[File:lilliputdesktop.jpg|center|400px|link=]]
-====Calibrating the touch screen====
-Unfortunately, by default the screen is calibrated to believe the bottom of the screen is on the right hand side.  This has the effect of making the touch functionality more or less useless until it has been properly calibrated.  To do this, install the following package:
-<div class="source">
 <syntaxhighlight lang=bash>
-apt-get install xinput-calibrator
+java -classpath .:/usr/share/java/phidget22.jar HelloWorldExample
 </syntaxhighlight>
-</div>
-Now use xinput calibrator to measure the parameters of your screen.  Launch xinput calibrator (called Calibrate Touchscreen in the programs menu) and follow the instructions on the screen.  The screen should now be functioning at full potential.
+Success! The HelloWorld example is running on your SBC. Now that you have a program running on your SBC, you may be interested in having it run automatically when the SBC boots, or maybe even on a schedule. Keep reading for more information.
+===Running a Program Automatically===
+After testing your program, you will likely want it to run on boot, or on a schedule, without your input.
-===Using a Different Wireless Adapter===
+====Run on Boot====
+Running on boot ensures that your program will never miss an event. As long as the SBC is running, your code will be running. This section assumes you have written and compiled your program on an external computer, and have uploaded it to the SBC Web Interface. If you are not using the SBC Web Interface, jump ahead to [[#Via a Boot Script|using a boot script]].
-The support for the wireless adaptor that Phidgets sells is written into the SBC kernel.  Hence, we do not support using other adaptors.
-However, Linux is very flexible, and it is possible (though not easy) to write a custom kernel for the SBC and add support for a new wireless adaptor.  We can't help you with this, but we do provide some basic guidelines for [[#Custom Kernel and Filesystem|building your own kernel]].  You can also have a look at our thoughts on our own experience with choosing a Wifi adapter: [[Alternative Wi-Fi Adapters on the SBC]].
+To have your program run on boot, navigate to Projects->ProjectName->Startup Settings in the SBC Web Interface. After selecting your project, copy the settings from the image below:
-===Using a Different Webcam===
-In addition to the webcam that Phidgets sells, you have the option to use many different webcams with the SBC.  There is a [http://www.ideasonboard.org/uvc/#devices long list] of compatible webcams.
+[[File:phidgetsbc_runonboot.PNG|link=|alt=|center]]
-The common thread for these webcams is that they use UVC - the USB Video Class - drivers for Linux.  You can then use [[#mount|mount]] to find out what video device your webcam is mounted under.
-===Taking Pictures With the Webcam===
+We will review some of the options that are shown in the image above:
+*Startup Order: lower numbers boot first. Booting later means more programs are available for use, booting earlier means other programs can use your program.
-Probably the most straightforward way to use a webcam for pictures rather than video is to use the {{Code|opencv}} library.  You can get it by:
+*Run as a daemon: starts the program as a daemon. Unless you have explicitly written your program as a daemon, leave this checked, or else your SBC may hang on boot.
+*Executable/Class name: your main Java class or C file.
+*Arguments: any command line arguments the program needs.
-<div class="source">
+After saving your changes, your program will run automatically whenever your SBC boots.
-<syntaxhighlight lang=bash>
-apt-get install libcv2.1
-</syntaxhighlight>
-</div>
-If there is no {{Code|libcv2.1}} package, you can perform {{Code|apt-cache search libcv}} to find the current version.
+====Run on a Schedule====
+Running your program on a schedule allows you to perform your task once a week, or once a minute without worrying about memory management issues or instability problems that may arise. It executes, and then gets cleaned up. To run your program on a schedule, we recommend using Cron. Cron can automatically schedule programs (known as ''jobs'', or ''cron jobs''). Cron simply reads a ''crontab file'' and runs whatever programs are listed, with whatever timing they are listed with. Cron runs continuously in the background, but the cron jobs only run as long as they naturally would, and then they exit.
-The opencv libraries can also be used within Python, by installing the link between them:
-<div class="source">
+Let`s set up your first cron job. We will use nano to edit the crontab file, but feel free to use whatever editor you prefer.
-<syntaxhighlight lang=bash>
-apt-get install python-opencv
-</syntaxhighlight>
-</div>
-Then taking pictures from within code becomes quite simple.  For example, in Python, taking and saving an image is four lines:
-<div class="source">
+First, set your editor to nano:
 <syntaxhighlight lang=bash>
-#! /usr/bin/python
+export EDITOR=nano
-import cv
-# The webcam is located at /dev/video0
-# OpenCV only needs the number after video
-webcam = cv.CaptureFromCAM(0)
-frame = cv.QueryFrame(webcam)
-cv.SaveImage("image.jpg", frame)
 </syntaxhighlight>
-</div>
+Next, edit your crontab file:
-For the complete OpenCV documentation, see [http://opencv.willowgarage.com/documentation/index.html The OpenCV Reference], and specifically the section on [http://opencv.willowgarage.com/documentation/reading_and_writing_images_and_video.html Reading and Writing Images].
-'''Note:''' The SBC is probably not as powerful for image processing and transport when compared to your desktop computer.  Try running your image processing code on the SBC from an early point in development.  During those test runs, you can visit the first System page of the [[#SBC Web Interface|SBC Web Interface]] to check the processor and memory use.  For more information on processor power, check the specification for your SBC (on the product page on [{{SERVER}} our main website]) as well as our discussion of [[#Pushing Processor Limits|pushing processor limits]] below.
-===Checking System Logs===
-The SBC maintains two logs: a kernel log and a system log.
-The kernel log is for low-level occurrences, such as devices attaching and leaving the USB hub, recording what drivers are being used, and so on.
-The system log (syslog) is for normal chatter from the operating system.  Any program with the right permissions can use it (though you need to know the method to write to it, information all around the Internet can help) and it contains everything from the Ethernet going up and down, to webserver requests, and so on.  If you don't run many programs or services on the SBC, the syslog will essentially be a mirror of the kernel log, because the kernel is the only thing talking.
-You can check these logs by using the web interface in the {{Code|System &rarr; Logs}} tab.
-Or you can perform more powerful filtering and displaying via an SSH terminal.  For example, {{Code|dmesg}} is the command to display the kernel log, and {{Code|tail}} prints the last ten lines of input.  So, if you are trying to see if you can get a device to be detected on USB, you can run <code>dmesg | tail</code> to print the latest ten lines of kernel log data.
-The actual locations of the log files (for filtering and reading) are:
-* {{Code|/var/log/syslog}}
-* {{Code|/var/log/dmesg}}
-But don't edit them directly!  Always follow the advice and procedures around the Internet on how to properly log items to syslog.
-===X Forwarding===
-Although most tasks can be done using the [[#SBC Web Interface|SBC Web Interface]] or [[#SSH|SSH]], you can also set up X11 forwarding on the SBC.  X11 is the window manager base, which provides a graphical windowing system on the SBC.  Although you probably won't connect directly to the X11 manager (i.e. by plugging a screen directly into the SBC), X11 also gives a user the ability to forward graphical windows over SSH.  You will need the following packages installed:
-* {{Code|x11-common}}
-* {{Code|xbase-clients}}
-After installing, make sure that the line in {{Code|/etc/ssh/sshd_config}} has a line that says:
-:{{Code|X11Forwarding yes}}
-Then log out and log back into the SBC.  This second time you log in, use the {{Code|-X}} switch to turn on X forwarding for that connection:
-:{{Code|ssh -X root@phidgetsbc.local}}
-Then you should be able to run programs that launch a window, and it will launch remotely and appear on the computer you have the SSH connection from.
-===Pushing Processor Limits===
-The SBC, though more powerful than many embedded computers out there, is probably about as powerful as your smartphone.  If you hook up 1 ms Phidget sampling devices to all six of its USB ports, events and packets will probably get lost.  The exact data rates you can accomplish depend on:
-* What else is running on the SBC
-* How efficient your code is for external operations (like File I/O)
-* Other minor details (e.g. the temperature of the SBC, etc)
-If you want to achieve data rates as fast as possible, try these tips:
-* Program in C, not in an interpreted language (Python, Java, .NET)
-* Perform file I/O as little as possible.  Locally cache data, manage your writing to a file in a separate thread, and use low-level write calls.
-* Change the [[#Custom Kernel and Filesystem|filesystem]] to a faster, non-compressed file system.
-** Alternatively, use a high-data-rate USB key.
-* Keep other running processes to a minimum.
-** If you are running code locally right on the SBC, turn off the Phidget Network Server.
-===Custom Kernel and Filesystem===
-You can compile your own kernel and flash it to the board. It is left up to the user to configure an appropriate cross-compiler for kernel development. You may also be able to compile a new kernel on-board.  We have a kernel development kit, complete with patch file and README:
-* [{{SERVER}}/downloads/libraries/phidgetsbc2-kerneldev.tar.gz SBC Kernel Development Package]
-Compiling a new, custom kernel is somewhat complex.  If the SBC is your first experience with Linux, writing a custom kernel will be difficult.  However, it will probably also be very rewarding because you can put whatever you like into it.  We might be able to offer additional suggestions, but ultimately you're on your own here.
-You may be able to write a custom kernel right on the SBC, but the easiest way is to develop the kernel on an external computer.  And the easiest way to develop on an external computer is for that computer to also be Linux, even just in a Virtual Machine.  The time spent loading a copy of Linux into a virtual machine (such as VirtualBox, which is free) onto your computer will probably be less time than setting up a standard compiler on Windows to cross-compile.
-On your external Linux system, you will need:
-* A cross-compiling toolchain for the ARM processor, which we briefly describe on the [[OS - Linux#Cross-Compiling with a Custom Toolchain | main Linux page]], and
-* The [{{SERVER}}/downloads/libraries/phidgetsbc2-kerneldev.tar.gz SBC Kernel Development Package] from the Phidgets website.
-The kernel development kit has a brief README file which describes how to obtain the proper kernel and patch, configure, customize, and build it.
-We have an application guide in progress, which walks through building a custom kernel to add Bluetooth support to the SBC.  Please contact us if you would like more information.  Even if you are trying to add support for hardware other than a bluetooth modem, or wondering if support even exists in the kernel for your modem (3G, alternate wireless, etc) you will probably find the application guide helpful.  Follow it up to the point where you run the program {{Code|menuconfig}} (you don't need an SBC to do this), which will give you a menu of all drivers you can enable in the SBC kernel.
-After making your new kernel, you should have a uImage and modules target for your Makefile.  At this point you can transfer your kernel files onto the SBC, make their targets, and transfer them into the nand memory.  This involves erasing the old kernel, flashing the new kernel, installing the new kernel modules, and rebooting.  From the SBC, in the kernel directory:
-<div class="source">
 <syntaxhighlight lang=bash>
-make uImage; make modules
+crontab -e
-flash-eraseall /dev/mtd3
-nandwrite -p /dev/mtd3 arch/arm/boot/uImage
-make modules-install
-reboot
 </syntaxhighlight>
-</div>
+Finally, schedule your cron job:
+<syntaxhighlight lang=text>
-Custom kernels can also be flashed from the [[#Recovery System | Recovery System]].
+#cron job that will run at 5AM every week:
+5 * * 1 /root/code/myprogram argument1
-If you need to create a root filesystem image, the filesystem type is UBIFS, and the commands to create it are:
-====For SBC2:====
-<div class="source">
-<syntaxhighlight lang=bash>
-mkfs.ubifs -m 2KiB -e 126KiB -c 4050 -r $ROOTFS/ system_ubifs.img
-ubinize -o system_ubi.img -m 2KiB -p 128KiB -s 512 ubinize.cfg
 </syntaxhighlight>
-</div>
-Where {{Code|ubinize.cfg}} contains:
+[[File:phidgetsbc_cronjob.PNG|link=|alt=|center]]
-<div class="source">
-<syntaxhighlight lang=bash>
-# Section header
-[rootfs]
-# Volume mode (other option is static)
-mode=ubi
-# Source image
-image=system_ubifs.img
-# Volume ID in UBI image
-vol_id=0
-# Volume size
-vol_size=64128KiB
-# Allow for dynamic resize
-vol_type=dynamic
-# Volume name
-vol_name=rootfs
-# Autoresize volume at first mount
-vol_flags=autoresize
-</syntaxhighlight>
-</div>
-====For SBC3:====
+After entering your task, simply save and exit the file.
-<div class="source">
+====Run Using a Boot Script====
-<syntaxhighlight lang=bash>
+If you want your program to run on boot, you can install your program into the boot order using a script. This process is covered [[OS - Linux#As A Service|here]].
-mkfs.ubifs -F -m 4KiB -e 248KiB -c 4000 -r $ROOTFS/ system_ubifs.img
-ubinize -o system_ubi.img -m 4KiB -p 256KiB ubinize.cfg
-</syntaxhighlight>
-</div>
-Where {{Code|ubinize.cfg}} contains:
+===Programming===
+Ready to write some code? Select one of the programming languages below:
-<div class="source">
+*[[Language - C|C]]
-<syntaxhighlight lang=bash>
+*[[Language - Java | Java]]
-# Section header
+*[[Language - Python | Python]]
-[rootfs]
+*[[Language - JavaScript | JavaScript]]
-# Volume mode (other option is static)
+*[[Language - C_Sharp | C#]]
-mode=ubi
-# Source image
-image=system_ubifs.img
-# Volume ID in UBI image
-vol_id=0
-# Volume size
-vol_size=83MiB
-# Allow for dynamic resize
-vol_type=dynamic
-# Volume name
-vol_name=rootfs
-# Autoresize volume at first mount
-vol_flags=autoresize
-</syntaxhighlight>
-</div>
-You then flash ‘system_ubi.img’ (not ‘system_ubifs.img’) from the recovery system.
-Again, like the custom kernel creation, the need to create a custom root filesystem is essentially non-existent except for those advanced users who already know they need it... and furthermore, you are almost entirely on your own.
-===Saving a file system to flash to multiple SBC's===
-You may want to create a complete backup of your SBC root filesystem, which can then be flashed to other SBCs. This is how it could be done:
-You will need a USB drive - we have had issues using cheap flash drives, so a real USB drive is recommended. Make sure it's empty, as it will be reformatted.
-All of these commands are executed on your SBC, while logged in over SSH.
-First, re-format the USB drive as ext3. Assuming the USB drive is sda and has a single partition:
-<div class="source">
-<syntaxhighlight lang=bash>
-umount /dev/sda1
-mkfs.ext3 /dev/sda1
-mount -t ext3 /dev/sda1 /media/usb0
-</syntaxhighlight>
-</div>
-Then, remount / as readonly, so it doesn't change as we're copying it. To do this, we need to kill all running processes except sshd:
-<div class="source">
-<syntaxhighlight lang=bash>
-service udev stop
-service ifplugd stop
-service rsyslog stop
-service avahi-daemon stop
-service phidgetNetworkserver stop
-service ntp stop
-service busybox-httpd stop
-service dbus stop
-service cron stop
-pkill dhclient
-mount -o remount,ro /
-</syntaxhighlight>
-</div>
-If the remount says that / is busy, do a 'ps auxww' and 'pkill' anything else that may be running until it remounts properly.
-Then, copy / to the flash drive:
-<div class="source">
-<syntaxhighlight lang=bash>
-mkdir /media/usb0/root
-mount --bind / /mnt/
-cp -a /mnt/* /media/usb0/root/
-</syntaxhighlight>
-</div>
-Then, clean up the copy - removing files specific to this board. We also remove the APT cache to save space.
+==Phidget Network Server==
+The Phidget Network Server is an extremely useful feature of Phidgets that allows you to remotely control Phidgets over your network. If you haven't already, check out the  [[Phidget Network Server]] page for a complete overview.
-<div class="source">
+===Try it Out!===
-<syntaxhighlight lang=bash>
+The Phidget SBC comes with the Phidget Network Server installed, and the SBC automatically starts the Network Server on boot. In order to change any of this default behaviour, navigate to Phidgets->phidget22NetworkServer using the SBC Web Interface:
-find /media/usb0/root/var/log -type f -print0 | xargs -0 rm -f
-rm -rf /media/usb0/root/var/lib/apt/lists/*
-mkdir /media/usb0/root/var/lib/apt/lists/partial
-rm -f /media/usb0/root/var/cache/apt/*.bin
-rm /media/usb0/root/etc/udev/rules.d/70-persistent-net.rules
-rm /media/usb0/root/etc/ssh/ssh_host_*
-</syntaxhighlight>
-</div>
-then, create the ubinize.cfg file:
-For SBC3:
-<div class="source">
-<syntaxhighlight lang=bash>
-cd /media/usb0
-cat > ubinize.cfg << EOF
-[rootfs]
-mode=ubi
-image=/media/usb0/system_ubifs.img
-vol_id=0
-vol_size=83MiB
-vol_type=dynamic
-vol_name=rootfs0
-vol_flags=autoresize
-EOF
-</syntaxhighlight>
-</div>
-For SBC2:
-<div class="source">
+[[File:phidgetsbc_networkserver.PNG|link=|alt=|center]]
-<syntaxhighlight lang=bash>
-cd /media/usb0
-cat > ubinize.cfg << EOF
-[rootfs]
-mode=ubi
-image=/media/usb0/system_ubifs.img
-vol_id=0
-vol_size=64128KiB
-vol_type=dynamic
-vol_name=rootfs
-vol_flags=autoresize
-EOF
-</syntaxhighlight>
-</div>
-NOTE: you may need to increase vol_size if your filesystem is larger.
-then, create the UBI image from the copy:
+In order to try the Phidget Network Server out, you will need a host computer, and a client computer:
+*Host computer: the computer that is physically connected to the Phidgets via USB and is running the Phidget Network Server.
+*Client computer: a computer running a Phidgets application that accesses Phidgets connected to the host computer.
-For SBC3:
-<div class="source">
+For this example, we will use the Phidget SBC as the host computer. The next step is setting up your client computer. If you are using a Windows computer as your client, keep reading, otherwise, you can jump ahead here:
-<syntaxhighlight lang=bash>
+*[[#macOS Client | macOS Client]]
-mkfs.ubifs -F -m 4KiB -e 248KiB -c 4000 -r /media/usb0/root /media/usb0/system_ubifs.img
+*[[#Linux Client | Linux Client]]
-ubinize -o /media/usb0/system_ubi.img -m 4KiB -p 256KiB ubinize.cfg
-</syntaxhighlight>
-</div>
-For SBC2:
-<div class="source">
+====Windows Client====
-<syntaxhighlight lang=bash>
+In order to remotely access Phidgets on your SBC, you should get your client computer set up. Follow the Getting Started guide for Windows below before continuing:
-mkfs.ubifs -m 2KiB -e 126KiB -c 4050 -r /media/usb0/root /media/usb0/system_ubifs.img
+*[[OS - Windows#Getting started with Windows| Getting started with Windows]]
-ubinize -o /media/usb0/system_ubi.img -m 2KiB -p 128KiB -s 512 ubinize.cfg
-</syntaxhighlight>
-</div>
-then, unmount the drive to ensure everything is written out properly:
-<div class="source">
+Now that you have Phidget drivers and libraries installed on your client computer, we can test the Phidget Network Server by following the steps below:
-<syntaxhighlight lang=bash>
-umount /dev/sda1
-</syntaxhighlight>
-</div>
-Then, you can remove the /root/ folder and system_ubifs.img. system_ubi.img can be flashed to other SBCs using the recovery system.
+. Open the Phidget Control Panel on your client computer. You will see something like this:
-==Software Details==
-For even more advanced uses of the SBC, it may help to know the gritty details of the SBC software system.
+[[File:Phidgetsbc_networkserver_windows.PNG|link=|alt=|center|]]
-;Operating System
-:Debian/GNU Linux
-:Kernel 2.6.X or higher (generally kept up to date with latest releases, use {{Code|uname -r}} to check the kernel version)
-;Main Filesystem (rootfs)
+. You now have access to the Phidgets that are connected to your Phidget SBC. Try double-clicking one of them to bring up an example.
-:UBIFS (a raw flash type of file system)
-:Mounted in a 460 MB Nand partition (in Read/Write mode)
-;Kernel
+====macOS Client====
-:uImage format
+In order to remotely access Phidgets on your SBC, you should get your client computer set up. Follow the Getting Started guide for macOS below before continuing:
-:Has its own 3MiB partition on bare Nand
+*[[OS - macOS#Getting started with macOS| Getting started with macOS]]
-;Web Interface Scripts and Configuration Data
-:Located in {{Code|/etc/webif}}
-:Modifying these scripts can be done; however, it is very easy to enter invalid data that could cause the system to behave unexpectedly or not boot.
-;User Applications uploaded through Web Interface
+Now that you have Phidget drivers and libraries installed on your client computer, we can test the Phidget Network Server by following the steps below:
-:Located in {{Code|/usr/userapps}}
-;Webcam Device Location
+. Open the Phidget Control Panel on your client computer. You will see something like this:
-:{{Code|/dev/video0}}
-:Numbers increase with more webcams
-;Date and Time
+[[File:Phidgetsbc_networkserver_macos.PNG|link=|alt=|center|]]
-:Set using ntp (network time protocol) at boot
-:The ntp daemon continues to run in the background and will periodically update the clock
-:The network keeps the SBC very close to real time
-:Also there is a real-time clock with battery backup which will preserve date/time across reboots, power removal
-:The real-time clock is synced to system time during reboot/shutdown
-:If power is unplugged suddenly, and the network not restored, the real-time clock may not have the correct time
-;Wireless Networking System
+. You now have access to the Phidgets that are connected to your Phidget SBC. Try double-clicking one of them to bring up an example.
-:Wireless adapter support for the wireless adapter that Phidgets sells is written into the kernel
-:It supports WEP and WPA
-:It is best configured through the configuration interface.
-;Nand Layout
+====Linux Client====
-:The board contains 512MiB on Nand. This nand is split into 7 partitions as follows:
+In order to remotely access Phidgets on your SBC, you should get your client computer set up. Follow the Getting Started guide for Linux below before continuing:
-:0: u-boot		 size: 256K		 Read Only
+*[[OS - Linux#Getting started with Linux| Getting started with Linux]]
-:1: u-boot_env		 size: 128K		 Read Only
-:2: recovery_kernel	 size: 2M		 Read Only
-:3: kernel		 size: 3M		 Writable
-:4: flashfs	 	 size: ~3.625M	 	 Read Only
-:5: recovery_fs		 size: ~ 43M		 Read Only
-:6: rootfs		 size: ~ 460M		 Writable
-: The final size of flashfs/recovery_fs/rootfs depends on the image size at production, and on the number/location of bad blocks in the NAND.
-: '''Note''': U-Boot and recovery kernel and filesystem cannot be written from Linux - this is a safety measure.
-;Boot Loader
-:U-Boot is used for setting up the processor and booting Linux, and is only accessible via a serial connection.
-:Normal users will not need to use or modify it.
-:Be very careful when modifying the u-boot partition. If it is damaged or overwritten, it is difficult to fix.
-:When using U-Boot, a prompt will appear via serial shortly after power on.
-:The environment variables will help you determine how to boot Linux on the SBC
-:You can also refer to the [http://www.denx.de/wiki/DULG/Manual U-Boot documentation]
-;Boot Process
+Now that you have Phidget drivers and libraries installed on your client computer, we can test the Phidget Network Server by following the steps below:
-:From power on...
-:1. Processor loads first 4 bytes from NAND into Steppingstone and runs it.
-:2. Steppingstone sets up RAM, copies u-boot from NAND into RAM and runs U-Boot.
-:3. U-Boot initializes the processor, sets GPIO state, etc., copies the linux kernel into RAM, sets up the kernel command line arguments, checks that the kernel image is valid, and boots it.
-:4. Linux boots, bringing up USB, Networking, NAND, etc. and then mounts the rootfs NAND partition on /.
-:5. init gets run as the parents of all processes, as uses the /etc/inittab script to bring up the system. This includes mounting other filesystems, settings the hostname, and running the scripts in /etc/init.d, among other things.
-:6. inittab then turns the green LED on.
-:7. inittab then sets up a getty on the first serial port, ready for interfacing using the debug board.
-==Appendix==
+. From the terminal, type in the following command:
-===Useful Commands===
-You will likely be interacting with the SBC's operating system over the command line, either via a keyboard and monitor, or, using SSH. This section discusses some useful commands and how to run them.
-'''Note''': You can use the {{Code|man}} command  at any time when using the Phidget SBC to access the system manual:
 <syntaxhighlight lang=bash>
-man ls
+ phidget22admin -s
 </syntaxhighlight>
-To save you some time, we have compiled a list of common commands you may be interested in:
+You will now see something like this:
-====ls====
-The '''ls''' program lists the contents of a directory.
-It will show both files and folders, but not files that start with a "." (these are hidden files on Linux).
+[[File:Phidgetsbc_linuxphidgetadmin.PNG|link=|alt=|center|]]
-*If you also want to show hidden files, use {{Code|ls -a}}
-*If you want more information, such as size and date modified, use {{Code|ls -l}}
-*Commands can be combined, like {{Code|ls -al}}
-====cd====
-The '''cd''' program changes to a new directory.
+As shown in the image above, the server running on your SBC can now be seen over the network. You will now be able to remotely access any Phidgets connected to your SBC.
-For example, {{Code|cd /root}} changes into the directory at the base of the file tree called ''root''.
-Note:
+===What's Next?===
-* Linux uses forward slashes
+Now that you have seen the Network Server in action, you may be interested in implementing an application that takes advantage of all it's features. Luckily, every programming language we support comes with example code on how to do this! Jump to [[#Programming|programming languages]] above.
-* The base of all directories is "/" (not "C:\")
-* The tilde symbol (~) is short for your home directory (i.e. when you are root, this is short for "/root")
-* The double dot ".." means move one directory higher (for example from {{Code|/root/data/}} to {{Code|/root/}})
-====pwd====
+==Advanced Information==
+===Writing Image to SD Card===
+{{SDCardImage}}
-The '''pwd''' program prints the current directory you are working in.  ('P'rint 'W'orking 'D'irectory)
+===Checking System Logs===
-For example:
+The SBC maintains two logs: a kernel log and a system log.
-:{{Code|root@phidgetsbc:~# pwd}}
-:{{Code|/root}}
-====cp, mv, and rm====
+The kernel log is for low-level occurrences, such as devices attaching and leaving the USB hub, recording what drivers are being used, and so on.
-These programs are copy ('''cp'''), move ('''mv'''), and remove ('''rm''').
+The system log (syslog) is for normal chatter from the operating system.  Any program with the right permissions can use it (though you need to know the method to write to it, information all around the Internet can help) and it contains everything from the Ethernet going up and down, to webserver requests, and so on.  If you don't run many programs or services on the SBC, the syslog will essentially be a mirror of the kernel log, because the kernel is the only thing talking.
-Copy copies a file from one location and pastes it to another.
+You can check these logs by using the web interface in the {{Code|System &rarr; Logs}} tab.
-For example, if you have a file {{Code|data.txt}}, typing {{Code|cp data.txt data_backup.txt}} will put a copy of the file {{Code|data.txt}} into {{Code|data_backup.txt}}
+Or you can perform more powerful filtering and displaying via an SSH terminal.  For example, {{Code|dmesg}} is the command to display the kernel log, and {{Code|tail}} prints the last ten lines of input.  So, if you are trying to see if you can get a device to be detected on USB, you can run <code>dmesg | tail</code> to print the latest ten lines of kernel log data.
-Move moves a file (this is also useful for renaming files) to a new destination.
+The actual locations of the log files (for filtering and reading) are:
+* {{Code|/var/log/syslog}}
-For example, if you have a file {{Code|data.txt}}, typing {{Code|mv data.txt data_backup.txt}} will put the contents of {{Code|data.txt}} into {{Code|data_backup.txt}}, and then will remove {{Code|data.txt}}.
+* {{Code|/var/log/dmesg}}
+But don't edit them directly!  Always follow the advice and procedures around the Internet on how to properly log items to syslog.
-Remove deletes a file.
+==Further Reading==
-For example, typing {{Code|rm data.txt}} will delete {{Code|data.txt}}.
-Note that '''rm''' is final.  Once you remove a file using {{Code|rm}}, it is gone forever.  There is no recycle bin, no temporary trash, nothing other than backups you may have personally created in the past!
-Directories can only be removed with {{Code|rmdir}}, and then only if they are empty.  If you want to remove a directory and all the files in it, use {{Code|rm -rf directory}} but be '''very, very careful''' with this command.  Trying to remove everything within a directory (e.g. {{Code|rm -rf *}}) is one of the most dangerous commands you can run on a Linux system, as running it from the wrong directory will result in Linux happily removing everything under that directory -- which could be your entire filesystem.
-====find====
-The '''find''' program does what it says - it finds things.
-Unfortunately for the casual user, the find program is very flexible and powerful, and thus not especially intuitive to use.  But, here are some examples:
-{| style="border:1px solid darkgray;" cellpadding="15px;"
-|-
-! SSH Command
-! What it Does
-! Example
-|-
-| {{Code|find folder -name file.txt}}
-| Looks for all files in a folder (/ for root - or all - folders) with a certain name (* for wildcard)
-| {{Code|find / -name *.jpg}}
-|-
-| {{Code|find folder -mtime +X}}
-| Looks for all files in a folder modified less than X days ago
-| {{Code|find /root -mtime +30}}
-|}
-====grep====
-The '''grep''' program takes text input and searches for a term.
-For example, if you type {{Code|mount}} to view what devices are mounted (e.g. loaded) on your SBC, you will see:
-<div class="source">
-<syntaxhighlight lang=text>
-root@phidgetsbc:~# mount
-tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
-proc on /proc type proc (rw,noexec,nosuid,nodev)
-sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
-udev on /dev type tmpfs (rw,mode=0755)
-tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
-devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
-rootfs on / type rootfs (rw)
-procbususb on /proc/bus/usb type usbfs (rw)
-/dev/sda1 on /media/usb0 type vfat (rw,noexec,nodev,sync,noatime,nodiratime)
-</syntaxhighlight>
-</div>
-This may be a lot of information you don't need.  If you are only interested in a USB key attachment (as described in the [[#Using USB Data Keys|Using USB Data Keys]] section), you can use grep to filter that one response:
-<div class="source">
-<syntaxhighlight lang=text>
-root@phidgetsbc:~# mount | grep sda1
-/dev/sda1 on /media/usb0 type vfat (rw,noexec,nodev,sync,noatime,nodiratime)
-</syntaxhighlight>
-</div>
-====nano====
-The '''nano''' program is a small text editor that you can use within an SSH terminal.
-Nano can be surprisingly useful for writing short lengths of code right on the SBC, so there is no need to transfer files and keep track of different file versions on different computers.
-Nano has all keyboard commands which are listed at the bottom of the screen at all times as a reminder (Ctrl-O to save, Ctrl-X to exit, these expand with a larger terminal window).  And, nano provides what is called 'syntax highlighting', which colours reserved keywords, comments, strings, and so on as appropriate to the programming language you are using.  Nano detects the programming language via the extension of the file ({{Code|.java}} for Java, {{Code|.c}} for C/C++, and {{Code|.py}} for Python).
-Typing {{Code|nano test.py}} on an SSH command line and then entering a few lines of Python into the new empty file results in:
-[[File:sbc_nano_python.png|link=|alt=]]
-====apt====
-The '''apt''' program allows you to install, uninstall, upgrade, and search software available for the SBC.
-For a non-Linux user, the apt framework may be daunting at first, but it actually allows you to keep your system up to date and install and manage software quickly, easily, and for free.
-'''Note:''' Before installing anything on the SBC, make sure that the ''Include full Debian Package Repository'' option is checked in the web interface under {{Code|System &rarr; Packages}}.
-{| style="border:1px solid darkgray;" cellpadding="15px;"
-|-
-! SSH Command
-! What it Does
-! Example
-|-
-| {{Code|apt-cache search term}}
-| Looks for all programs (packages) that have {{Code|term}} in the title or description
-| {{Code|apt-cache search opencv}}
-|-
-| {{Code|apt-cache show package}}
-| Shows a lot of data about {{Code|package}} including size, version, etc
-| {{Code|apt-cache show unzip}}
-|-
-| {{Code|apt-get update}}
-| Gets the most recent listing of available software
-| {{Code|apt-get update}}  (No options)
-|-
-| {{Code|apt-get install program}}
-| Installs {{Code|program}} from the internet
-| {{Code|apt-get install python}}
-|-
-|}
-====mount====
-The program {{Code|mount}} shows you all of the mounted devices on your SBC.
-For example:
-<div class="source">
-<syntaxhighlight lang="text">
-root@phidgetsbc:~# mount
-tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
-proc on /proc type proc (rw,noexec,nosuid,nodev)
-sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
-udev on /dev type tmpfs (rw,mode=0755)
-tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
-devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
-rootfs on / type rootfs (rw)
-procbususb on /proc/bus/usb type usbfs (rw)
-/dev/sda1 on /media/usb0 type vfat (rw,noexec,nodev,sync,noatime,nodiratime)
-</syntaxhighlight>
-</div>
-For the non-Linux user, the concept of a device may be quite strange.  To give a short summary, everything on Linux that you can read or write is a file.  Webcams are files (i.e. you can 'read' photos from them), USB keys are files, and each filesystem (tmp storage, the kernel portion, the main filesystem) are also themselves files.  These files specify what and how something can be written.  These are not necessarily linear, for example, you can see above that the USB key ({{Code|/media/usb0}} is mounted ''within'' the root file system {{Code|rootfs}} which is /.
-So mount gives you an idea of what devices have been 'mounted' for reading or writing, and how you can read and write to them.  More information on mount (and its various forms, like {{Code|umount}}) is available widely around the Internet.
-====which====
-The program {{Code|which}} tells you if and where a program is installed.
-For example, on a default SBC, typing {{Code|which python}} will return no results.  But after successfully [[#Installing Python | installing python]], it will return {{Code|/usr/bin/python}} as the location of the python program/binary/executable.
-===Some Useful Commands to Install===
-These are other programs you may find useful on the command line.  Although they are not on the SBC by default, these and other programs can usually be installed simply by using [[#apt|apt-get install]], with the exception of gcc.  For example, {{Code|apt-get install wget}} will download and install [[#wget|wget]].
-'''Note:''' This section and the section on [[#Some Useful Commands|pre-installed commands]] can hardly cover all of the complexities and power of the Linux operating system.  There are many excellent tutorials online, and between them and using [[#apt|apt]] to find and install programs you should be able to learn a lot and perform any number of complex useful tasks.
-====gcc====
-The '''gcc''' program is the C compiler for Linux.
-If you are an experienced C/C++ user on Mac or Linux, or if you've already read our [[Language - C/C++ | C Language page]], you might think you need to install gcc via {{Code|apt-get}} to compile C code.  However, gcc is not in the package repository for the SBC, so {{Code|apt-get install gcc}} will fail.  Rather, to install gcc, you can do it via the web interface, as described in the [[#Installing C/C++ and Java|Installing C/C++ and Java]] section.
-After installing it via the SBC web interface, you can use {{Code|gcc}} normally.
-====less====
-The '''less''' program displays the contents of a text or source code file.  When displaying the file, {{Code|less}} allows you to scroll up and down to read it.
-This is useful if you are writing your sensor readings to a data file, and you want to read the data file while it is being written by your main code.  If your data file is called {{Code|data.txt}}, you can type {{Code|less data.txt}} and see the lines in the file, and what they are.
-The {{Code|less}} program output can also be piped into another program.  For example, you can use {{Code|less}} and the word search program {{Code|grep}} to find lines within a file with a search term.  For instance, if you have a C source code file {{Code|Program.c}} on the SBC, and you want to see all the lines in {{Code|Program.c}} that contain a variable name {{Code|var}}, you can type:
-:<code>less Program.c | grep var</code>
-====wget====
-The '''wget''' program allows you to get an online file (over http) and download it to the SBC.
-For example, to get the source file (HTML) from the Phidgets home page, you can type:
-<div class="source">
-<syntaxhighlight lang=bash>
-wget http://www.phidgets.com
-</syntaxhighlight>
-</div>
-This is most useful for downloading libraries, drivers, or anything (zip, tar, etc) you need from the web which is not available by [[#apt|using apt]].