8514/A Standard: Who
Wants It?
IBM forges on with 8514/A standard: But who wants it?by Tom Williams, Computer Design V27, n16 Sep 1, 1988 pgs 36-40
With the inexorable force of flowing lava, the 8514/A graphics standard oozes from the depths of IBM-regardless of whether the world wants it. The questions "Is it good? Is it appropriate?" pale next to the fact that it's there and third-party graphics hardware and software manufacturers are rallying to support it. They're also working to improve its performance and price.
Conceived by IBM as an option that would allow the high resolutions needed by CAD applications to run on its Personal System/2 family, the 8514/A offers 1,024 x 768 pixels at either 4 bits (16 colors) or 8 bits (256 colors) per pixel. The 8514/A chip set makes up a drawing processor that takes commands from the host CPU to update pixels in its frame buffer. This is a departure from earlier IBM graphics modes-Color Graphics Adapter (CGA), Enhanced Graphics Adapter (EGA) and Video Graphics Array (VGA)- in which the host had direct access to the frame buffer's memory map.
In addition, the 8514 display specification has two modes: 1,024x 768 pixels interlaced, and the VGA display mode of 640- x 480-pixel non-interlaced scan. Although the 8514/A controller doesn't run VGA graphics software, it can input VGA signals via a special-feature connector and display them on a multiple-frequency monitor at the VGA resolutions.
IBM hasn't released specifications on its controller hardware but has published a document describing the Adapter Interface, or AI, the software interface to the 8514/A silicon. The AI is the interface to which IBM recommends all third-party software developers write their code. IBM's stance forces hardware and software
developers who want 8514/A functionality to make an important decision: do they follow IBM's recommendation and write to the AI, or do some daring hardware companies try to reverse engineer the silicon so that software can be written directly to hardware registers? Additional issues revolving around 8514/A involve
devising ways that let the earlier applications written to EGA and VGA work with 8514/A hardware and lowering the cost of high resolution monitors needed to meet the display requirements.
"Hardware Compatibility-is it useful? Maybe, but probably not.''
- Walt Penny, Media Cybernetics
Reverse engineering tempting
The question of writing directly to the hardware is probably the most crucial. Reverse engineering worked well with EGA and VGA, and a large number of companies are building boards using register-compatible chips supplied by five or six IC manufacturers. It appears tempting on the surface. "In all cases, you'll get better performance by writing to the hardware," says Walt Penny, vice-president of engineering for Media Cybernetics (Silver Spring, MD), maker of a graphics toolkit called Halo, which has found wide acceptance on current graphics hardware.
The only problem is that IBM has warned that it may change the silicon underlying the 8514/A AI at some time in the future, in which case software written to earlier silicon wouldn't work.
"IBM said that about everything CGA, EGA and VGA," asserts Greg Reznick, director of marketing for Video Seven (Fremont, CA), whose company currently provides a VGA board using a register-compatible chip and is now developing an 8514/A chip set. Video Seven is banking on the assumption that IBM's warnings
will turn out to be as empty as they've been in the past.
Others, however, aren't so sure. Media Cybernetics' Penny, for example, says that this time he's taking IBM seriously, noting that the Entry Systems Division-producers of PCs and PS/2s - has recently been more closely tied to the corporate center. And IBM's corporate tactic for dealing with plug-compatible manufacturers
that are trying to emulate its hardware has been to keep changing the hardware.
Verticom (Sunnyvale, CA), which is readying a family of 8514/A-compatible
products, is also being cautious. "We're probably at a point where the warning is going to go teeth in it," says Robert Dickenson, president and chief executive officer at Verticom.
Al has serious flaws
Despite disagreement over whether IBM will change the silicon underlying the 8514/A AI, just about everyone agrees that the AI as it currently stands is seriously wanting. Video Seven's Reznick calls it a "not-too-far- removed plotter driver." Indeed, while the 8514/A AI specification does include bit block transfer (bitblt)
commands, it's heavily oriented toward line drawing and has quickly gained a reputation for being poor at large block transfers.
Furthermore, some criticize Al's lack of a full suite of graphics commands. "AI isn't full-featured," claims F. Stephen Andes, president of Enertronics Research (St. Louis, MO), producer of the Aurora 1024- one of the first 8514/A boards for the
AT bus. "Even in CAD/CAM applications, we wish it had an arc routine and a circle routine." And Media Cybernetics' Penny, comparing the AI to Hitachi's HD 63484 advanced CRT controller and Intel's 82786, says, "The AI doesn't do a lot of the
things that are native instructions in other graphics processors. We wrote the Halo toolkit to the AI because we had no choice."
Given such dissatisfaction with the features and functions of the AI, it's no wonder that third-party vendors are divided into two camps. One camp is trying to improve the AI while staying within the safe fold of striking out to reverse engineer and
write directly to the hardware, the risks be damned. Indeed, Microsoft (Redmond, WA) itself has gotten the 8514/A hardware specifications from IBM. Its sole purpose is to write Windows and Presentation Manager drivers-not drivers for application programs-to the 8514/A silicon because the performance simply wasn't
acceptable when the drivers were written to the AI.
But what happens if IBM does change the hardware? "The driver for Presentation Manager [and Windows] will have to change," says Verticom's Dickenson.
Video Seven, which claims to have successfully reverse engineered the 8514/A chip set, will be offering the specifications under nondisclosure to selected software companies so they can write both to IBM's present hardware and to Video Seven's yet unannounced hardware. This news hasn't exactly set off a chorus of cheers, however. "Can Reznick prove it's 100 percent compatible? It can't be 99
percent," cautions Kathleen Hunter, marketing communications director for Enertronics. And Media Cybernetics' Penny wonders, "Hardware compatibility-is it useful? Maybe, but probably not."
Working around compatibility
Graphics-based user environments, such as Windows and Presentation Manager, and toolkits for building graphics applications, such as Media Cybernetics' Halo, have already adapted to a lack of hardware compatibility. Media Cybernetics has
written a version of Halo to the AI, but is also preparing a version that directly accesses not the 8514/A hardware but the TMS34010 graphics processor from Texas Instruments (Dallas, TX). This is significant because the initial third-party 8514/A products appearing on the market such as the Aurora 1024 from Enertronics, the Cobra/2 from Vermont Microsystems (Winooski, VT) and the
MX series from Verticom - implement a version of the AI but use the 34010 as the under lying hardware.
Large software vendors who provide system-level graphics environments such as Halo and Windows want to get as close to the hardware as possible because most application developers will want to use a toolkit of some kind rather than writing in
terms of low-level graphics primitives. This makes it vital that such toolkits be as efficient as possible. Media Cybernetics, for example, worked hard to write Halo to the AI because there were certain things that Halo does that aren't directly supported by the Al's functions. These Halo operations had to be worked out by the CPU in terms of the limited AI command set rather
Page 39 multiple columns
capability on the card, but are viewed as transition products.
Another issue regarding the 8514/A is that of cost for the required high resolution monitor. When one moves from 640x480 to 1,024 x 768 pixel resolution, the price of the monitor needed for display takes a quantum jump from less than $1,000 to around $3,000. This price differential represents a barrier to wider acceptance of 8514/ A, although there are indications that prices will soon come down. For this reason, says Verticom's Dickenson, "For the next 12 to 24 months, the high-resolution market is still a vertical one."
It's possible to use a multisynchronous monitor such as the NEC Multiscan with an 8514/ A card and get the graphics performance it offers (a definite improvement over VGA) but at the VGA screen resolution. This may provide an impetus for the three-element feedback loop that Dickenson sees as essential for lowering prices:
standards, software and low-cost monitors. "The critical thing for something being mainstream is that it has to be accepted as a standard, and then it feeds on itself," he says. Software developers have something to write to, and the existence of applications presents a market to which monitor manufacturers can sell at higher volumes and, hence, reduced unit prices.
"The 8514/A isn't the ideal controller for shading operations, and it's not very fast.''
- George Krucik, Autodesk
Whatever criticism one may have of the 8514/A, it still represents a defined standard, if only because it comes from IBM. Large software vendors such as Autodesk (Sausalito, CA), which produces the AutoCAD drafting program, are supporting it, but they're also trying to influence IBM to extend the AI. "The 8514/A still isn't the ideal controller for shading operations, and in its current incarnation,
it's not very fast," says George Krucik, manager of future development for Autodesk. But he adds that IBM has solicited comments from Autodesk about improving performance characteristics and may implement some of those suggestions.
The big question is, Will those improvements come in the form of extensions
to the AI, changes in the silicon or both? Until an answer begins to emerge, the prudent software developer would do well to stick with the AI, for all its present faults.