oreilly.comSafari Books Online.Conferences.


The Sharp Zaurus -- A Lovely Little Computer

by Simson Garfinkel

Editor's Note: The Sharp Zaurus SL-5500 retails for $499. This new GNU/Linux-based PDA is making a splash in the open source community, and we recently asked Simson Garfinkel to take it for a spin and give us his opinion of the device. Simson is the author of Web Security, Privacy & Commerce, 2nd Edition, Database Nation, and co-author of the recently-released Building Cocoa Applications: A Step- by-Step Guide.

With its GNU/Linux-based operating system and applications, Sharp's new Zaurus SL-5500 palmtop computer is turning heads in the open source community. Powered by the Qtopia desktop from Trolltech (the makers of Qt), this is a handheld that's equally at home viewing Web pages with its Opera Web browser, running enterprise C++ and Java applications, or managing your contacts. For people and companies who are used to programming desktop computers, the SL-5500 provides an easy way to get those programs into your pocket and on the road.

But while it's tempting to focus on the SL-5500's open source roots, doing so actually does a disservice to this machine. The SL-5500 is completely usable by folks who don't care that they can get at this computer's source code. For them, the real strength of the SL-5500 is not its software, but its hardware.

The SL-5500 is the sort of PDA that James Bond would use: although it looks small and unassuming at first, each side opens up, slides away, or unfolds to reveal capabilities that are both unique and useful.

Starting with its face, the SL-5500 has a brilliant 65,536-color reflective LCD screen that is equally visible in total darkness, dim light, room light, and in direct sunlight. The screen is protected by a frosted polycarbonate visor that flips up or detaches. Directly beneath the screen are two LEDs: one indicates charging, the other blinks to indicate that you have mail, part of the SL-5500's expected wireless Internet service.

Beneath these indicators are the now-standard complement of PDA buttons that bring up the calendar, contacts book, menu, email, and applications browser. There's also a circular "cursor button" that lets you steer up/down/left/right, an OK button, and buttons labeled "On/Off" and "Cancel."

Photo of a Zaurus.
The Zaurus SL-5500 with the keyboard exposed.

Like other handhelds, the SL-5500 has a touch-sensitive screen you can use for launching applications, clicking menus, and entering text using either an onscreen keyboard or handwriting recognition. Or, you can be like James Bond and pull down on the sides of the SL-5500, which causes the PDA to open up and reveal a 37-key QWERTY keyboard that's reminiscent of RIM's BlackBerry.

Along the top edge of the SL-5500 you'll find a headphone jack (this device can play MP3s and MPEG-1 Videos), a hole for the stylus, a hole for a handstrap, and a full-size compact flash (CF) socket, meaning you can put a gigabyte of storage on the thing using the IBM Microdrive. The left edge has an infrared port and a slot for an SD card.

The bottom edge has a "Sharp I/O Port" (used for the docking station) and a power jack (so you can charge it without docking). And the back panel opens up to reveal the replaceable Lithium-ion battery, which means you can pack extra power for those camping trips. (Unfortunately, you'll need it: the 950 mAh battery only supports one hour of continuous use with the back light turned on, or 10 hours of 'typical' use with the back light turned off, according to Sharp.)

Compared with a Compaq iPAQ3800-series, the SL-5500 is half an ounce heavier (7.4 vs. 6.8), and both taller and thinner. (The SL-5500 is 2.875" x 5.6" x 0.825"; the iPAQ is 3.25 x 5.25 x 0.62). Powered by the Intel StrongARM 206Mhz processor (the same as the iPAQ), the SL-5500 comes with 64MB of RAM that's divided into 32MB of scratchpad and a 32MB RAM disk. Integrated software allows you to back up the system to compact flash or the SD slot.

All in all, the hardware is super cool -- the only significant flaw is the tiny plastic door that covers the Sharp I/O Port, a door which must be manually opened when you drop the SL-5500 into its cradle and manually closed when you take it out. Where the Zaurus falls down, ironically, is with its software.

The SL-5500 is very Linux-like: it's got a ton of cool features, but they are poorly integrated. What's worse, many of the advances in usability developed over the years on other platforms are simply missing from the SL-5500. It's as if this machine's developers spent their time studying photographs and screenshots of existing products, rather than actually using them.

To be sure, the SL-5500 comes with a lot of built in applications -- more than two dozen (see Table 1). You can access them by clicking the "home" button that's over the cursor key. You can also get an application menu by clicking the Trolltech logo in the lower left-hand corner, which functions like the "start" menu in Microsoft Windows. It all looks familiar, but it's subtly different.

For example, the Qtopia "start" menu is somewhat buggy -- although you can click on the menu, drag to the application that you want, and release, the menu doesn't work properly if you are in the habit of selecting each submenu with its own click. Presumably, click-dragging is the method the developers used, and they never bothered to adequately test the other gesture.

Similarly, if you click the calendar button on a computer running PalmOS, the calendar immediately opens to show today's appointments: press the button again, and you'll cycle through views of the current week, the current month, and so on. Likewise, repeatedly pressing the Calendar button on the SL-5500 causes the Calendar application to cycle through the day, week and month views -- but the developers forgot the critical step of instructing the application to show the view for the current date. As a result, when you click the Calendar button, you need to manually check the to make sure that the Zaurus is actually displaying today, as opposed to next week. (Even worse, there is no "today" button --- you have to choose the "today" command from the "View" menu.)

Related Reading

Building Cocoa Applications: A Step by Step Guide
By Simson Garfinkel, Michael Mahoney

Click on the calendar to make an appointment, and you'll discover another usability problem: this gesture, which is universal among calendar applications, doesn't work on the SL-5500. To create a calendar entry, you need to choose "New event" from the "Data" menu. Similar usability problems permeate the companion Qtopia desktop that runs on Windows-based PCs. Fortunately, since this is an open source system, it will probably get better.

Sharp says that all of these usability problems are being addressed, and to be fair, there are already some applications available for download from SourceForge that overcome these missteps.

I hope they can fix the SL-5500's on/off problems as well: although you can turn on a PalmOS-based computer or a PocketPC by pressing any of the special buttons on the bottom, the only way to turn on the SL-5500 is by pressing and holding the On/Off button along the bottom. Sharp told me this behavior is so that the computer doesn't accidentally turn on in your pocket. I think there should be a better way.

Like PalmOS- and PocketPC-based systems, the SL-5500 comes with a cradle that does double-duty for both charging and synchronization. The cradle connects to a Windows-based PC over a USB port. But here the similarity ends. Whereas other PDAs open up a serial connection between the desktop and the PDA, the SL-5500 actually runs TCP/IP over the network, using a proprietary version of PPP that Sharp developed to run over a USB bus -- a brilliant move on Sharp's part.

Using TCP/IP for sync means that the SL-5500 is equally at home syncing over USB, Ethernet, or an 802.11 wireless LAN. (In fact, the Linux OS includes built-in drivers for the most popular 802.11 CF cards.) It also means you can do a lot more than just sync your Zaurus over the USB.

You can browse the Web using its built-in Opera browser. You can transfer files with "ftp," or log into remote systems with "telnet" (the Zaurus doesn't come with ssh and scp pre-loaded, but you can download them.) In theory, Sharp should be able to further capitalize on its use of TCP/IP and the open source Qtopia desktop, and support people using Mac OS X, Linux, FreeBSD, and other operating systems. Perhaps one day -- but for now, Sharp only supports Windows, at least officially.

In my testing, getting the SL-5500 to sync with either Outlook or the Qtopia Windows desktop was not difficult, although the Qtopia Desktop has usability problems similar to those with the handheld environment. My only problem happened when I installed it on Windows XP and ran afoul of XP's built-in firewall: unless you disable the firewall, the USB-based TCP/IP doesn't work.

Looking forward, Sharp needs to push Trolltech to improve the usability of the underlying software. Sharp should also add a USB hub to the Zaurus so it could be used with external keyboards, like the Happy Hacker, as well as other USB devices like cameras, printers, and camcorders.

Sharp is firmly pitching the SL-5500 as a mobile organizer. But it's important to remember that this computer is more powerful than most desktops were just a few years ago. With its ease of application development and deployment, I expect the SL-5500 to become a favorite at universities and among the open source elite.

Table 1: Built in SL-5500 Applications


Address Book
City Time
HancomPresenter (PowerPoint clone)
HancomSheet (spreadsheet)
HancomWord (wordprocessor)
Help Browser
Image Viewer
Media Player
Opera Browser (Web browser)
System Info
Terminal (must be separately downloaded)
Text Editor
To-do List
Voice Recorder


Mindbreaker (Mastermind)
Mine Hunt
Patience (Solitaire)
Word Game

Insignia Jeode Java Runtime

Control Panes

Add/Remove Software
Application Key (reprograms buttons)
Backup Restore (to SD card or Compact Flash)
Beam Receive
Internet Wizard
Light & Power
Network & Sync
Proxim Configuration (802.11 wireless support)
Wireless LAN

Simson Garfinkel is a developer with 24 years of programming experience, the author or coauthor of 14 books, an entrepreneur, and a journalist. He is the founder and Chief Technology Officer of Sandstorm Enterprises, a Boston-based firm that develops state-of-the-art computer security tools.

Return to the Linux DevCenter.

Linux Online Certification

Linux/Unix System Administration Certificate Series
Linux/Unix System Administration Certificate Series — This course series targets both beginning and intermediate Linux/Unix users who want to acquire advanced system administration skills, and to back those skills up with a Certificate from the University of Illinois Office of Continuing Education.

Enroll today!

Linux Resources
  • Linux Online
  • The Linux FAQ
  • Linux Kernel Archives
  • Kernel Traffic

  • Sponsored by: