The Basics of The Palm Pre Linux

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Table of Contents

0. Introduction
1. SDK Installation
2. Start to work with Linux
3. Program Installation
4. System folders review
   1. Standard system directories
   2. Specific Directories of Web OS
5. Work with FTP on the Palm Pre
   1. Data exchange procedure
   2. Work with console client ncftp
6. References

Introduction

This article describes the process of initial configuration and basic work with Palm Web OS on the lower level than it's described in Palm SDK docs.

Palm company released (http://www.palm.com/us/products/phones/pre/) the new smartphone managed by GNU Linux based operating system. This product becomes more and more popular due to the cute GUI, well-documented SDK and easy start on the development. But nevertheless many low-level features of this system are poorly documented.

This article will be useful for those who start working with the console interface of GNU Linux generally and Palm Web OS in particular. It may be useful also for the developers who need more capabilities than Mojo SDK provides to solve their task.

In this article, we'll consider such questions:

1. SDK installation and configuration
2. Accessing Linux using "novacom" utility. Basic Linux commands
3. Installation of additional utilities (sudo, package manager etc.). Configuration of the virtual machine (virtualbox). Install\remove packages.
4. Short description of the system files and directories specific for Palm Pre
5. Work with FTP on Palm Pre, review of some file content

This article is some kind of review.

1. SDK Installation

I used emulator from the Palm Mojo SDK package to research the features of Web OS.

You can download it from the official site, or use this link (no registration).

Choose the platform you need on the download page (Figure 1) and then follow the instructions on the site and in Install Wizard. It's better to install Java first, then VirtualBox, and then SDK. Such order decreases the possibility of errors.

During the installation, the virtual machine for Palm Web OS will be created. You don't have to create it manually.

2. Start to Work with Linux

To start work with Web OS Linux, start the emulator. You can use either the shortcut created by the installation program (figure 2) or VirtualBox interface (figure 3).

If everything is ok, then you'll see the Emulator window (figure 4). We'll need the Internet connection for further work. It should be configured only in the host system (in our case, it's Windows). You can check if there is Internet on Emulator simply starting Web Browser. To do it, choose Programs (right bottom icon) => Web. After that, try to open some site just like on the computer. Search something for example (figure 5).

Now we should use the novacom.exe utility to connect to the device. To get the full information about the program options, enter:

novacom.exe --help

The command:

novacom.exe -t open tty://

opens the Linux terminal window.

Note: Like in the usual Linux, more than one terminal can be opened in Web OS.

First let's browse the file system. ls command is used for this. After entering it, we see the content of the current directory (root by default).

To distinguish files from directories, we an use option ls -F.

Directories now have / symbol at the end. So as you see, we have only three files in the root directory: wget, log.txt, md5sums.

When using ls -F, some other symbols can occur at the end of the file names.

You can see the examples by entering commands:

ls -F /bin

ls -F /tmp

More detailed information about the file system element type can be obtained by means of file utility. This utility is disabled in Palm Web OS by default. Later, we'll consider how to install it.

To browse the file content, use the command cat <filename>.

For example,

cat md5sums

To obtain full information about the command, enter <command> --help, or search the Internet with keywords "man <command>". You can also read the help in the full Linux version entering "man <command>".

I propose that the reader also learn such commands as rm (remove files\directories), mkdir (make directory), touch(create file), cp (copy), pwd (get current path).

3. Program Installation

The process of the program installation for Linux is a bit different from this process in Windows. Unlike other systems, Linux has repositories. Repository can be considered as the database that contains program, libraries, and relations between them. There is some special software that manages repositories and installs software on the local computer. Such software is called “package manager”. The package manager compares software versions on the computer and in the repository, downloads software, resolves conflicts between packages. More information about package managers can be found in the articles [4],[5],[6],[7].

By default, Palm Web OS does not have a package manager. To install it, use the guide available here.

The script optware-bootstrap.sh performs the following:

1. Formats /dev/hdb for its needs
2. Installs package manager ipkg-opt
3. Creates the list of repositories /opt/etc/ipkg/optware.conf
4. Installs the sudo program, creates the user with the root (administrator) rights
5. Installs ssh, sftp server.

In the original script, some of the mentioned actions cannot be performed on the emulator (for example (4)). It's also required to have /dev/hdb device. By default, there is no such device on the emulator so you should add it manually. Detailed instructions can be found here.

I've put the fixed version of this script into the attachments to this article. It allows the user to change disk for installation and also is free from the limitations for the emulator.

To start the fixed script, you should get it on the device using the wget command. To organize file exchange with the device, you can install FTP server on your computer or other computer in your local network.

After entering the command...

wget ftp://192.168.0.60/optware-bootstrap-edited.sh

... the file will be uploaded to the device файл to the current directory (IP address should be of the computer with FTP server of cause). DON'T use symbol names of the machines, for example..

wget ftp://my_computer_name/optware-bootstrap-edited.sh

... as far as Web OS won't be able to convert them to the address correctly.

So, we have executed the script and installed a lot of useful programs. Now we have package manager and so we'll be able to install all missing programs. To do it, use the following command:

ipkg-opt install <package name>. 

For example:

ipkg-opt install file

The list of the packages can be browsed by the command:

ipkg-opt list 

or by following this link.

Developers and enthusiasts may want to install gcc compiler, gdb debugger, make utility, python interpreter and other great things. The presence of these utilities allows program installation by means of building from the source texts.

4. System Folder Review

Let's start from the folders that are common for all Linux systems.

4.1 Standard System Directories

1. /bin, /lib, /home,

   These are folders for standard utilities from Linux package, shared libraries (Windows *.dll analogues) and user files correspondingly.

2. /mnt, /media, /lost+found

   The access points to the external data storages (floppies, hard disks, optical disks) are stored in these directories. In the Palm memory card (micro sd) can be mounted to this directory. And there is nothing interesting there on the emulator.

   Note: The lost+found directory is specific for the extX (ext1, ext2, ext3, ext4) file systems.

3. /dev

   Device files are stored here.

   • /dev/hd[a..z][1..N] – logical partitions of hard disk
   • /dev/hda1 – root file directory
   • /dev/hdc – bootloader
   • /dev/hdb – the section we created earlier or the physical data storage of the real device – 8GB (~7GB user available)
   • ttyN – console devices
   • null – «black hole», eating all information that is entered into it

4.2 Specific Directories of Web OS

1. /var/luna/data/dbdata/

   There are databases used by high-level applications of Web OS.

   Bases PalmDatabase.db3 and PalmAccountDatabase.db3 is in sqlite format. There are data of such applications as mail accounts, notes, calendar, chat, memo stored in them.

   They can be browsed by any sqlite viewer (see [9]). I would like to advise this one http://link.osenxpsuite.net/?uid=homepage&id=sqlite2009pro.zip.

   We will discuss how to exchange files with Palm Pre in the next section.

2. /var/luna/data/mediadb.db3

   The data about the locations of images, music, movies etc. are stored here. After analysis, I can say that these data are stored in the directories: /media/internal/, /usr/palm/ and their subdirectories.

3. /var/luna/data/emails

   The text of email messages is stored in this directory in HTML and ASCII formats.

4. /usr/share/dbus-1/system-services

   Here you can find Java services (or, if you like, deamons). Using them in the application developed with the usage of Mojo SDK can get access to the low-level components of the system.

5. /usr/lib/luna/java

   Here java library files (*.jar) are stored, they are used by services.

5. Work with FTP on the Palm Pre

5.1. Data Exchange Procedure

Well, now we know what and where it is situated. But it's not very convenient to research file content directly on Palm Pre. So we have a task of getting files from the device.

One of the methods is FTP protocol. And so you should:

1. Install FTP server (for example this one) to one of the computers in the local network you work in (for example on your own one).
2. Install the FTP client on your computer. It can be the plugin for Far Manager or Total Commander, or it can be separated application – for example FileZilla FTP client.
3. Install FTP client to the Palm Pre:
   

   ipkg-opt install ncftp

4. Use ncftp to transmit data to the server (it will be described later).
5. Get data from FTP server to your computer.

5.2 Work with Console Client ncftp

To connect to the server, enter:

ncftp <url>

or:

ncftp
open <url>

Remember that:

<url> = ftp://<Ip Address>/ 	symbol names are not allowed
<url> = <bookmark name>

When the connection is established, the current local directory is «frozen». Instead of working with the directory, all commands of navigation in the file system are translated in the commands of the FTP and processed by the server.

Now, after you choose the necessary remote directory, data exchange can be performed:

put <filename>
get <filename>

You can also use some mask instead of the argument. For example, put *.txt

To send the directory, use the command put -R <dir_name>

Ncftp also supports such commands as mkdir, rm, rmdir, pwd.

The same commands but with l- prefix are used to navigate in the local file system: for example lmkdir, lls, lpwd etc.

You can find the full list of the commands on the official program site here.

Find more Mobile Development articles at Apriorit site.

References

1. http://developer.palm.com/
2. http://www.palm.com/us/products/phones/pre/
3. http://www.webos-internals.org/wiki/Next_steps
4. http://www.control-escape.com/linux/lx-swinstall.html
5. http://www.linuxforums.org/forum/linux-tutorials-howtos-reference-material/64958-how-install-software-linux.html
6. http://www.linuxcenter.ru/lib/articles/system/rpm_howto.phtml
7. http://www.debian.org/doc/manuals/apt-howto/index.ru.html
8. http://www.webos-internals.org/wiki/PalmDatabase.db3_File
9. http://www.sqlite.org/cvstrac/wiki?p=ManagementTools
10. http://link.osenxpsuite.net/?uid=homepage&id=sqlite2009pro.zip
11. http://ipkg.nslu2-linux.org/feeds/optware/i686g25/cross/unstable/Packages
12. http://filezilla-project.org/download.php?type=server
13. http://filezilla-project.org/download.php
14. http://www.perpetualpc.net/srtd_commands_rev.html
15. http://ncftp.com/ncftp/doc/ncftp.html

History

• 21^st September, 2009: Initial post