The Sharp Zaurus SL-5600 is the flagship of the Linux-based PDAs. Thanks to its hardware and software, the device has the potential to rival any PDA on the market. Unfortunately, Linux has traditionally been synonymous with the phrase "difficult to use." Can a Linux-based PDA be easy to use? Can it stack up against a Palm or Pocket PC offering? I decided to take a look.

The Hardware
After installing and charging the rather large lithium-ion battery, the Zaurus sprang to life. The 3.5” reflective TFT LCD front-lit display delivers a very bright picture—bright enough to be used in full daylight. With 65,536 different colors, the palette is lush and saturated. The 240 x 320 resolution gives the image space a fair amount of real estate; the screen doesn't appear crowded or cramped. Except in very bright sunlight, the glare on the display is well within tolerable limits.

This Zaurus SL-5600 comes with a QWERTY keyboard hidden underneath a sliding navigation panel. The thumb-typing keyboard allows for much improved typing speeds. It has a function key that permits additional characters on the tiny surface. In my testing, I had a few problems with the keyboard. First, no Esc key is available. This might not seem a major problem, but programmers who are devoted to the VIM text editor know that they can use the Esc key to switch between modes by default. The VI improved editor was one of the first software packages that I installed on this hardware. Another problem I experienced is that the keyboard becomes useless in the dark—with no light on the keys, touch typing with thumbs is impossible. The other hardware input device, the stylus, is a tad short.

The 400MHz Intel XScale processor does an excellent job driving the graphics. The 512KB of ROM allows for acceptable response times. However, these features lead to an underwhelming battery life. On average, 3 hours was the most it could muster in my tests. I’m sure that the shortened battery life was partly due to the extended use I gave it because of its "new toy factor." The Zaurus SL-5600 has features that attempt to extend its battery life. It turns off the front light if it registers no activity for a couple of seconds. The media player lets you turn off the display when you're listening to music. These features help, but if you're entering lots of text or just playing games, don’t expect much more than 2 to 3 hours of battery life.

The navigation panel has buttons for the Calendar, Address Book, Home, Start Menu, Email, Cancel, OK, and a finger mouse. The finger mouse gives you a workable input device for games. The other buttons are useful in their default configurations, but you can also assign them different functions. I didn't like that the navigation panel's Cancel button doubles as the On/Off button.

The Zaurus SL-5600's form factor offers some good and some bad. The hidden keyboard is a nice feature, permitting an acceptable overall length. The thickness is also on par with some of the more powerful PDAs on the market. The bad news is the location of the battery, which adds additional thickness and an unsightly bump on the back of the PDA. The Zaurus SL-5600 comes with a clear plastic flip-style screen cover. This cheap-looking screen cover is actually quite sturdy and functional. It definitely doesn’t add to the looks, but it does its job without requiring you to purchase a leather-style case.

You can add goodies onto the Zaurus SL-5600. A digital camera card is available, and connectivity software for the camera is provided on the CD-ROM out of the box. More than one wireless card is available, as are two versions of a full-sized keyboard. Wireless versions connect through the IR port on the side, and hard plug-in versions plug into the cradle port.

The GUI
Trolltech provides a Qt-based GUI called Qtopia. The GUI's layout and controls are familiar and easy to use. The main screen consists of a tabbed desktop that divides the application offerings. The main interface permits personalization with color themes and background images, and you can also customize the tabbed navigation. Navigation is intuitive. The desktop metaphor is understandable and never hinders operation. However, this isn't a Pocket PC—it shares much more in common with the Palm OS. The full version of Qt gives you more control over the appearance of the buttons, and I would have liked to see that level of control in the Qtopia package.

Detailed Tech Specs
Hardware: Intel XScale (400MHz)
Platform: OS:Linux 2.4 (OpenPDA), Linux based embedded operation system (OpenPDA)
Memory: Flash Memory: 64MB (User area: Approx. 33MB)
ROM: 512KB
RAM: 32MB SDRAM
Display: Reflective TFT LCD with front light 3.5" with 240 x 320 pixels, 65,536 colors
Input device: Touch panel and QWERTY keyboard
I/O device: Serial/USB (via Docking Station port, IR (IrDA, 115.2Kbps), stereo headphone jackCF card slot, SD card slot (no copyright protection feature)
Power: AC adapter: “EA-70” 5.0 V (DC)Battery: “EA-BL08” 3.7 V (DC) lithium-Ion battery
Power consumtion: 3.4 W (with battery)
7.8 W (with AC adapter)
Battery life: When you display the Day view mode screen of the Calendar application continuously with the frontlight turned off:
Approx. 18 hours
When you play MPEG1 files continuously with the frontlight turned on at its brightest level:
Approx. 2 hours
Sharp 5600
The Software
The pre-installed software that comes with the Zaurus SL-5600 is also user-friendly. However, although application compatibility is good, it's by no means complete. The Hancom office applications seem to be able to open even the most complex documents, spreadsheets, and presentations. Unfortunately, complex formulas, graphics, and macros tend to suffer. The applications sometimes warn of incompatibilities, but sometimes they don't. Nevertheless, I was impressed with the Hancom office suite. Compatibility was good for software that's not made by Microsoft. The included email, calendar, to-do list, and address book were all quite functional with big, clear interfaces. But the base software packages contain some annoying flaws. For example, the calendar alarm doesn't provide an easy way to change the .wav file. I was able to find the file myself and replace it, but the software made the task difficult. I would have liked to have seen a more robust set of options for all the included software.

Numerous third-party software offerings for the Zaurus SL-5600 are available on the Internet—both commercial and free offerings galore. I found drawbacks in the third-party software. Some common useful applications are either unavailable or of low quality. I was disappointed by the lack of a decent banking package.

The graphical keyboard takes up a lot of screen real estate and is slow to use with the stylus. The Zaurus SL-5600 also has a handwriting-recognition mode. The software uses natural character recognition opposed to the simplified letter forms of Palm’s Graffiti. I had difficulty getting the handwriting application to consistently recognize uppercase and lowercase versions of letters. However, the handwriting application began accurately recognizing letters with just a minimum of training. The two other offerings for input are the Pickboard and the Unicode graphical inputs. The Pickboard is a quick method for entering words. The Unicode input method gives a list of all special characters that are available in the Unicode character set.

Connectivity
You can obtain synchronization software for the Qtopia desktop for Macintosh, Widows, and Linux using the RPM package format. (A few more synchronization packages are available on the Windows side.) The synchronization software on the Windows side works brilliantly. Unfortunately, I can't say the same for the Linux side. I used the SUSE 9.0 distribution method and thought this distribution would already contain this software. The Zaurus SL-5600 has been out for some time now. Not only did the distribution provide no Zaurus synchronization software but the SUSE distribution couldn't connect to the PDA without the addition of a kernel module. I was able to find instructions for connecting the USB cradle to the SUSE distribution on a user support site. The procedure wasn't terribly difficult, but I would much rather that the support be built into the distribution.

Internet
The Zaurus SL-5600 has no built-in wireless capability, although it supports a Compact Flash (CF) wireless card. All the utilities necessary for wireless connectivity are present. I was able to test the Opera browser only with an HTML file that I imported onto the Zaurus. I'm a fan of the Opera browser because it's easy to use. This version has a scaling feature that permits more information on screen by zooming in or zooming out. Opera doesn't, however, permit landscape viewing. The Qtopia email client has one small drawback: It doesn’t format HTML mail. The rest of the email application is intuitive and functional.

Media Player
The unit's media player and voice recorder are straightforward. MP3 playback, with headphones plugged into the stereo jack, is comparable to that of most digital audio devices. Playback on the mono single speaker is of unbearably low sound quality. The 64MB of built-in flash memory lets you store a fair number of songs before you need to add a CF or Secure Digital (SD) memory card. The video playback of the media player is barely acceptable, and even low-quality MPEGs shear and drop frames. I wouldn't have believed that a PDA could have played a MPEG movie in the first place. The voice recorder works well through a built-in microphone and provides acceptable output through the built-in speaker.

OS
The saving grace of the Zaurus SL-5600 and of Linux in general is its flexibility and versatility. You can accomplish full ROM conversions and a myriad of alterations. Palm OS emulators are even available. I don’t believe that you can program on any other PDA with this kind of ease. With a few simple changes, you can have your Zaurus SL-5600 and desktop Linux looking exactly alike. The embedded Java Virtual Machine (VM) gives developers two choices when developing for this platform. Although Qt is easy to use and has ample documentation, Java has even more. By adding on one of the available full-size keyboards, you could leave the laptop at home.

A Love/Hate Relationship
So what's my final evaluation of the Zaurus SL-5600? I'm experiencing a kind of love/hate relationship with this device. Everything about the PDA itself is easy to use. It connects to the Windows platform without any undue stress. As a hobby toy for developing in unlikely places, maybe even surfing the Web at the local coffee shop hotspot, it is a likable PDA. As a business tool to rival the rest of the PDA offerings, the Zaurus SL-5600 falls short. The HP iPAQ puts a huge hole in the argument for the Zaurus SL-5600. The iPAQ has a QWERTY keyboard, a Linux OS ROM conversion, better Windows application compatibility, and much better software. I would be hard pressed to recommend this PDA to anyone but a Linux user. However, I'm distressed by the lack of support in most of the Linux distributions, in particular SUSE 9.0. The Palm OS enjoys a bevy of software offerings, but the Trolltech Qtopia desktop and the Evolution productivity software package were the only connectivity packages I could find for the Zaurus SL-5600.

The next generation of the Zaurus SL-5600 is already available in Japan and will eventually be available in the United States. The device has moved to a clamshell design. However, I don’t believe the design of the Zaurus SL-5600 is its weak point. The device needs better software, and I would like to see better support on the Linux OS. In time, the Zaurus SL-5600 will enjoy better support on the Linux distributions and better tie-ins for the major desktop offerings and their corresponding productivity suites of email, contacts, and calendars software.

Connected Home Magazine Rating (10 possible)
Hardware GUI Connectivity Interoperability Overall
7 6 5 4 5