Accelerated X

In the past, Unix (and Linux)-based

computing was largely associated with simplistic, old-fashioned (and sometimes plain ugly)

text-based displays.

But these days, most computing under Unix

and Linux is done in a highly graphical environment, based on MIT’s solid and

well-seasoned X Windowing System. In fact, it’s not uncommon to find users of such

systems spending their entire working life using environments such as KDE or Gnome, which

provide a highly user-friendly desktop, complete with drag-and-drop, pop-up windows and

the other nice things one has come to expect of a modern computing environment.

Under commercial systems such as Solaris, the X environment is

provided by commercial software that usually ships with the operating system.

However, Linux being largely free in nature,

is a special case. Linux (and other free-Unix environments such as FreeBSD) developers

cannot purchase X licenses for their chosen environment. href="http://computersathome.com/nov99/novissue.html"

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This led to the XFree86 project–a port

of the X Consortium’s standard X platform to Linux, but completely free.

X consists of two components–an X

server, and X clients. Contrary to what one would expect, X servers are actually installed

on the client platr.Because of the free nature of the XFree86 project, developers are

usually hampered by the fact that many graphics card manufacturers don’t wish to

reveal their source codes. While X servers for most graphics cards do exist in the XFRee86

environment, they’re usually "clean-room" ports, not based on source code

provided by the manufacturer. This typically leads to some inefficiencies that can slow

things down. (It should be noted, however, that most XFree86 drivers perform as fast as,

if not faster than, their equivalents under environments such as Windows).

Usually, this isn’t a problem, because

for most applications, the speed of the XFree86 X servers is more than sufficient. But for

applications like CAD, or some games, the performance of the free X servers can be a

show-stopper.

This is where Accelerated-X from Xi

Graphics steps in.

Accelerated-X is a set of drop-in

replacement X servers for many platforms (including many commercial ones such as Solaris)

that isn’t hampered by the unwillingness of developers to sign a nondisclosure

agreement (NDA) that many graphics cards manufacturers insist on before they provide

detailed documentation and even source code for driver development.

Xi Graphics obviously knows its business.

We installed their two Accelerated-X suites (one for desktop usage and one targeted at

notebooks) on a variety of platforms, ranging from low-end PCs, through high-end CAD

stations and low-and high-end notebooks. In each case, the performance difference was

startling.

For example, on my IBM Thinkpad 770

notebook, the standard X benchmarks showed a difference of nearly 20 times to the

performance of the equivalent XFree86 driver! (This was using XFRee86 3.3.3.1. A

subsequent release of version 3.3.5 added hardware acceleration to the driver for this

chipset, reducing the gap in performance to about 15 percent). Installation of the Accelerated-X products

was quite simple–drop in and mount the CD, run the provided setup program, supply the

serial number and registration information, and sit back while the setup program figures

out the best driver and settings.

Once installed, the Accelerated-X servers

neatly took over the functionality of the earlier X server, providing performance boosts

and sometimes a lot of features not available in the XFree86 product.

Accelerated-X products are highly modular

in nature, and driver updates are frequently available on the company’s Website,

offering new features as well as better performance.

A product like Accelerated-X is

sometimes a bit difficult to justify cost-wise, especially because the performance of

XFree86 drivers is usually very good for most supported accelerated display cards

(Accelerated-X provides performance boosts only on display cards built on accelerated

graphics chipsets, such as Trident, Matrox, NeoMagic, etc).

However, if you’re stuck with a

display card that you simply have to use, but for which no XFree86 driver is available or

whose performance is not up to the required level, then Accelerated X is the right product

for you.

Atul Chitnis is a director at Exocore Consulting www.exocore.com