Computer Graphics World

November 2008 28 n n n n Hardware business class or better, there is usually avail- able power on the plane. Let's get back to the initial question, though: Can a workstation actually be por- table? Display size, resolution, and graphics performance are usually critical to a work- station user, and those features are major power drains. So, if a portable workstation can survive on battery operation for more than two hours, that's considered pretty good. And when you pack that much power into a mobile machine, it ends up weighing as much as eight pounds (3.6 kg) or more. Workstation Displays e new crop of portable workstations has a 17-inch WUXGA (1920x1200) screen with 400-nit brightness. (More about nits later.) is year, LCD display technology has improved to the point where users can get an almost-perfect color representation. In the film industry, judge the color correct- ness by comparing it to Adobe's RGB color space, developed in 1998 to encompass most of the colors achievable on CMYK color printers. Today, some of the new mobile worksta- tions are expressing their display capability in terms of a percentage of Adobe color space. is is an awkward description be- cause of the seven-dimensional nature of the color space, and it begs the question: Which part of that color space is compromised? at undoubtedly will be a mar- keting debate among the suppliers. No matter, Lenovo maintains that it supports 72 percent of the Adobe color space, and HP maintains it sup- ports 100 percent, albeit with an exter- nal DreamColor monitor. e idea is to be able to pick a color on the screen and expect that color to show up on the printed page. Remember WYSIWYG? Well, we're getting pretty close to it now. e Lenovo inkPad W700 worksta- tion has a unique built-in color calibrator. A small sensor is located in the base, just below the space bar. When you close the lid, the display runs through a series of test colors and patterns; this process is moni- tored by the sensor, and the system then calibrates the screen so it is as color-accu- rate as possible. HP, on the other hand, is promoting the DreamColor aspect of its EliteBook 8730w mobile workstation. DreamColor is a per- fectly color-corrected monitor that HP intro- duced recently, starting with the LP2480zx monitor for the film and photo market. e LP2480zx external stand-alone monitor has a set of RGB LEDs to extend the color range. e LED panels fit as part of HP's DreamColor technology initiative, which encompasses higher-precision (true 30-bit, 3x10-bit per channel) and color- calibration technology. In the context of HP's mobile worksta- tions, the DreamColor external monitor provides calibration technology, but on a foundation of more conventional 24-bit (3x8-bit) color precision. Nevertheless, they are equipped with a WUXGA RGB LED backlight panel, and while HP is still tweaking the color spaces, the company is targeting 132 percent of the Adobe space (and 151 percent of RGB). e Dream- Color panel option on the mobile worksta- tions just recently began shipping. In addition to color balance, the screen's brightness and contrast are important as well, especially during DCC applica- tions. Brightness—or more correctly, lu- minance—is expressed in nits; one nit is equal to one candela (a unit of measure of the light's intensity) per square meter (1cd/ m 2 ). And bigger is better, so you want the most nits, or candelas, you can get for the dollar when selecting displays, whether as a stand-alone or on a laptop. Contrast, meanwhile, is a ratio and is based on black as the reference point. However, LCDs don't project a very good black; typically, the best they can offer is a very dark gray. So polarizing and wave fil- ters are placed in front of them to achieve a "blacker" black. is requires a brighter backlight, which in turn drives up power consumption. Contrast ratios for a good home theater TV will be between 5000- and 10,000-to-1. A midrange laptop will have a ratio of between 500- and 1000-to- one, and it is important to note that the contrast ratio impacts the display's ability to reproduce the color spectrum. e HP 8730w delivers 300 nits and an 800-to-1 contrast ratio, while the Lenovo W700 offers 400 nits with a 500-to-1 con- trast ratio. Powering the Displays e new mobile workstations are equipped with powerful GPUs, but have limited memory compared to their desktop coun- terpart. Typically a desktop will have a graphics add-in board with 1gb of video RAM, whereas a mobile workstation will typically have a maximum of 512mb. In the evolving mobile workstation mar- ket, Nvidia has jumped to an early lead, with vendors such as Dell, Fujitsu, HP, and Lenovo usually positioning the Quadro FX3700M and FX2700M in the standard configuration, with the AMD ATI FireGL V5725 offered as an option. GPUs from both companies support OpenGL 2.1, but The Lenovo ThinkPad W700 has some unique features, including a built-in Wacom tablet below the keyboard.

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