April 29, 2005

Windows Pocket PC and the Linux desktop

Author: Basuki Winoto

Linux and Microsoft's Pocket PC platform have different document formats. Since there is no automatic file synchronization program for Linux comparable to Windows' ActiveSync, Pocket PC users have problems not only with disparate file formats, but even file transfer between the two platforms. But there are ways to get them to talk to each other. I tested four of them and found that two worked well for me -- which doesn't mean the others won't work for you, just that I had trouble using them with my hardware and software.My PDA is a Dell Axim X30 equipped with an external memory expansion slot (MMC), infrared (IRDA), Bluetooth, and Wi-Fi (IEEE 802.11b). Therefore I can transfer my files four different ways. Each of them offers pros and cons.

External storage card (MMC) This is the modern equivalent of Sneakernet -- easy but inconvenient. To transfer files via MMC card, you need an MMC card reader for your Linux computer. My card reader is a Billionton SD/MMC Reader which uses the USB 2.0 interface, so Linux recognizes it as a USB drive. I can copy any files to and from it.

Infrared (IRDA) Most PDAs come equipped with IRDA, but most infrared devices refuse to work on Linux, and even if you can manage to make yours operational, you'll find that file transfers are very slow. Unless you already have your infrared device working or you don't have any other choice, avoid this option.

Bluetooth To take advantage of Bluetooth, you need a Bluetooth device on the desktop side. Finding a Linux-ready Bluetooth device may be difficult, and making it work may be more so. I use a Cadmus Bluetooth USB adapter (class 1) with gnome-obex-server. Obex (object exchange) is a protocol widely used for data transfer on small devices for both Bluetooth and IRDA. You can transfer files to and from the PDA by pushing them from the opposite side. Once you succeeded in transferring your files once, the process is convenient from that point on.

WLAN Wireless networking is convenient and relatively secure, but relatively difficult to set up on the PDA side. You need a Wi-Fi adapter and a Wi-Fi access point on your network, plus virtual private network (VPN) software, because WLAN file transfer on Pocket PC requires a VPN tunnel. I used the FreeSWAN project for my VPN.

After trying all four methods, I found external storage to be the easiest, and
Bluetooth the most convenient. IRDA and WLAN were a pain.

File formats

Once you've transferred your files from one platform to the other, you still have the problem of incompatible file formats. By default, Pocket Word uses its own file format. Its files have a .pwi extension. Even Microsoft Word users can't open .pwi files on their desktop.

The good news is that Pocket Word supports Microsoft Word file format
(.doc) as well. You can open .doc files and save files as .doc instead of
*.pwi using Pocket Word. This approach let me open my Pocket
Word files using OOo Writer and also let me read OOo Writer files saved as .doc in Pocket Word.

After spending some quality time with OOo, I found that it has a file format transfer feature called XMerge, but it doesn't work out of the box. You need to have Java and Ant to compile this feature from source. XMerge can merge Pocket Word file format (.psw) to OpenOffice.org Writer file format (.sxw). I hope OOo will add this format transfer feature out of the box someday.

Now that I have all the pieces working, I love to sit in a quiet corner with my coffee, turn on my PDA, and scratch out ideas, then transfer my files to my Linux desktop and edit my work using OpenOffice.org.

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