The overall design has also been called an "open notebook" because it looks like a small handheld notebook computer that's been opened. There is no screen hinge here, however, as the 8640 is a tablet. It's fairly compact with a footprint of about 9 x 7 inches. Its thickness varies between an inch-and-a-half and two inches, and it weighs about 2.5 pounds with the battery installed.

This is actually an interesting design solution that was also explored by Husky in several ruggedized Windows and Windows CE designs. That company was later bought out by Itronix, which is now General Dynamics Itronix.

While some tablets are a bit awkward to hold, that is not the case with the 8640. It has a very ergonomic design and is easy to hold and operate. If you look at the unit's backside shown in the image to the right, you can see bulges on the left and right side of the unit, and deep grooves inside of them. This way, you can comfortably hold the computer with both hands or with either the left or the right.

The centerpart inbetween is what makes the 8640 so versatile. Underneath the thick plastic cover is an expansion bay that can accommodate a variety of options. Our review unit contained a PC Card Type II slot and a SDIO Card slot. There is plenty of space in front of the PC Card slot so that it can handle extended cards. There is also an additional connector for other integrated peripherals. The cap itself can include different interfaces or house custom-built peripheral options. Ours had a USB host connector and a 9-pin serial plug. The cap is secured down with four screws and is totally waterproof thanks to a rubber O-ring seal.

The two bulges mentioned above also do more than just provide a good grip for you hands.

One of them houses the 17.8 watt-hour (7.4Volt/2,400mAH) rechargeable Lithium-Ion battery pack that, according to DAP, is good for as much as four working days under depending upon operating conditions. That's pretty phenomenal. To remove or replace it, you turn a spring-loaded thumbwheel until the battery pack is released. With this kind of battery life, take a spare with you and you never have to worry about finding an outlet.

The other side can contain either an integrated 1D and 2D CMOS imager or a 1D laser scanner. A rubberized trigger button sits in an ergonomically molded indent so you cannot miss it.

Below you can see the front of the very sturdily built 8640 and all of its sides. As if the super-tough ABS plastic body were not rugged enough, the device also has thick rubber bumpers on both the left and right sides. They cover all eight corners, making the unit virtually invulnerable.

The left side has a carry strap that also has an elastic loop to stow away the bright-yellow plastic stylus when it is not needed. The strap can be attached to either the left or the right side.

The top of the unit shows the power jack on one side and the scanner window on the other. Our unit came with serial and USB ports; other port arrangements can be ordered as well.

The bottom shows the surface-mount charging/dock connectors. Surface-mount connectors are more reliable and last much longer than pin-based connectors. To the right of the contact banks is an infrared window.

Below the screen, the 8640 has an integrated 61-key keyboard with separate numeric keypad. The alpha keys are arranged in the standard QWERTY layout. It is a 64%-scale arrangement -- small, but not too small to type. The oval keys are labeled black on gray, white or light-green backgrounds. They are easy to read and illuminated in the dark. The keyboard is full-featured, with F1 through F12 function keys and pretty much everything else you'd expect in a full keyboard. The keys provide both tactile and sound feedback (sound can be disabled). You need to press them fairly hard to register, and, as is the case on most most keyboards of this kind, they feel a bit wobbly.

How do you use the keyboard? From the looks of it you might think using the unit like a BlackBerry in thumbtype mode works best. That's the case to some extent, but the unit is too wide for the right thumb to comfortably reach the QWERTY keys. What that means is that, like with all mobile and handheld computers, every user will develop his or her own style.

There are some caveats. LCD manufacturers always focus on whatever's hot and in demand. The iPhone screen, for example, is so sleek and terrific because Apple needs millions of them and that pays for perfecting and then amortizing the latest technology. The 6.5-inch 640 x 240 pixel format, on the other hand, hasn't been much in demand for a decade, and even then it was a low volume product. As a result, the one used in the 8640 is far from state-of-the-art. It is transflective, which is good as that provides outdoor readability, but it uses older passive STN (super-twisted nematic) technology. STN is much slower than what we're used to in modern screens. There are also color shifts as you vary the vertical viewing angle. There was really not much DAP could do to improve the situation and still stay with the interesting "open book" design.

Internal memory consisted of 128MB of SRAM (about half of which was used by the OS), and 256MB of Flash (about 192MB available to users). Pop in a SD card and -- bingo -- gigabytes of storage. To see if larger format cards worked I inserted a 2GB SanDisk card. The 8640 immediately saw the card and loaded the 10-megapixel pictures on it without any problems.

DAP includes a number of additional programs like the CE Pad editor, a wave file recorder, a FTP server, etc. To get an idea of the real power of the system you need to look at the settings and control panels. Our test unit had over 30 of them. Many are the exact equivalent of panels you find in Windows XP whereas others are specific to Windows CE. There are also device-specific panels such as one that handles the integrated scanner or several that deal with connectivity, communications and security. In some areas the OS shows its mid-1990's origin as in numerous references to modems and dial-up, and some of the utilities and panels get pretty technical.

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