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