The Agenda VR3: Real Linux in a PDAby Chris Halsall
It looks like Agenda Computing will claim victory in the race to produce the first PDA that runs Linux out of the box and can be purchased by consumers. Unless delayed (again), consumer versions of the VR3 should begin shipping May 21st, 2001, with three colors to choose from.
A few different developer's editions of the VR3 have been available since November of 2000, for those willing to put up with alpha and beta quality software. These units are functionally identical to the commercial VR3 models, except for their blue-and-white translucent color scheme, and on earliest models, slightly different internal designs.
The VR3 is the smallest of the three Linux PDAs we're looking at in this series, on many scales. It is lighter than the iPAQ or the Yopy, weighing only 4 ounces, and it's physically smaller at only 3.1" by 4.4" (7.8cm by 11.3cm). It's also the least expensive, with the consumer version costing $249 US.
On some scales, however, being smaller isn't best. The VR3's display has the lowest resolution of the three, at only 160 by 240 pixels, 16-bit gray-scale. Think of the display as the same size, physically as well as in resolution, as the new Palm m100/m105 models, except with renderable space on the VR3 where the fixed Graffiti writing area exists on the Palm.
For the CPU, the VR3 uses the NEC VR4181 MIPS-based chip, a 32-bit processor running at 66 MHz. Both the developer and initial consumer models are equipped with 16MB of flash memory, and 8MB of regular RAM. A future model, the VR3r, is expected with additional RAM available, although when such models will actual appear may be the subject of more than a few betting pools.
User input is by way of a stylus on the touch-sensitive screen, which also includes a thin row of seven "soft buttons" at the very bottom of the input area. There are also seven physical buttons around the device (including power), plus a handy switch inside the stylus storage chamber. The VR3 wakes up when the stylus is removed, and returns to sleep when it is re-inserted.
Previously in this series: Linux on Your PDA
From your view, what are the advantages of running the Linux OS on your PDA compared to Palm or PocketPC?
Digital Io can be accomplished by way of the IrDA port, or a regular RS232 connection exposed by way of a cable plugged into the interface port on the bottom of the device. This port also has a proprietary interface which Agenda Computing have not yet documented, but plan to "in the future."
The device also has mono audio record and playback ability when a microphone and/or set of headphones are plugged into the audio jack. A piezo buzzer is used for normal audio generation needs. As an interesting extra feature, the VR3 includes a "Consumer IR Port" -- a high-intensity IR LED intended to allow remote control of consumer multimedia devices such CD Players, from distances much beyond normal beaming range.
Overall, the VR3 feels nice and natural in the hand, although those used to the Palm's textured plastic say that the smooth plastic finish of the VR3 is a bit different. One physical design feature I really like on the VR3 is the fact that the battery compartment cover, holding 2 AAA batteries, screws closed. I once lost an entire trade show's worth of contacts because of the Palm's insecure battery cover, so I really appreciate this feature.
The First Boot
When you first turn on an Agenda VR3, or reset it, it will take about a minute before it's ready to be a PDA. Fortunately, going through a full boot sequence is a rare requirement, as the device is in suspend mode most of the time, immediately available when the power button is pressed.
During the boot process, a full Linux 2.4.0-test9 kernel and OS environment is launched. The very first thing which runs is a boot-loader called PMON, that is the VR3's rough equivalent to the BIOS and LILO boot steps of a PC. Interactive control of PMON, along with upgrading the Linux images, is covered below.
Assuming PMON doesn't receive notice otherwise, it will transfer control to the installed Linux kernel, passing in which device to use as the root partition as a parameter. On the screen you'll see a console display, in a very tiny font, of the process of a Linux boot sequence.
After about 30 seconds, a screen calibration tool will appear, and the boot sequence will halt until the stylus has been pressed at five locations on the screen. Once completed the console display returns for a couple of seconds, and then a wonderful sight appears: the familiar cross-hatched pattern and X cursor of a launching X Windows system!
It takes a few more seconds for vrwm, the default window manager to initialize itself, and then the LaunchPad runs. This is a icon-based browser for launching applications, similar to the application icon view on the Palm OS. The LaunchPad is optional, and can be exited to save memory.
At all times, applications can be launched by selecting one of the soft buttons at the bottom of the display. On the far left is the Agenda logo which brings up a menu of applications. The other buttons launch applications directly, and by default bring up Contacts, To Do, Schedule, Notes, the Calculator.
The last soft-button on the VR3 is the Keyboard icon, on the far right of the button bar. It is special in that it launches (or hides) the virtual keyboard application, which also includes the handwriting recognition engine used for the VR3, recd. The character input engine is based on Xscribble, and is covered below.