New Video and Serial Buses promise much improved performance

by Alan Zisman (c) 1997. First published in Canadian Computer Wholesaler, April 1997

For the past few months, we?ve been looking at up-and-coming hardware changes?ways that the computers that you?ll be selling as 1997 progresses will be ?new and improved? over last year?s models. Not just faster, but implementing new technologies to let users do more in a simpler way than in the turbo-charged super-ATs that we?ve all become accustomed to.

We?ve seen how Intel?s MMX chips are adding the first major change to the processor?s instruction set since 1985?s 386. And how USB?Universal Serial Bus?will let users add peripherals with ease.

Well, get ready for yet another computer industry three-letter acronym? in this case, AGP.

AGP is another Intel innovation?in this case, standing for Accelerated Graphics Port. It?s designed to get around a potential problem with another three-letter acronym from Intel, the PCI bus. The PCI bus is the high-speed internal expansion bus on the current generation of PCs, and now on PowerMacs as well. Its 132 MBps bandwidth provides lots of room for future growth for hard drives, network adapters, almost anything we care to throw at it.

Except for video.

As video moves to 3D (a move hastened by MMX?s multimedia instructions), it threatens to overwhelm the PCI bus. Intel?s solution is moving the video to a new, dedicated bus?AGP. AGP is dedicated to graphics?it provides a direct connection between the CPU and the graphics processor, unlike the current PCI bus where the graphics card has to share bandwidth with the hard drive, network card, and other PCI devices. It?s specified to run at 66 MHz?twice PCI?s speed, and can be clock-doubled to a blazing 133 MHz.

As well, AGP devices can use some of the system?s general memory to store 3D textures. This will provide an effective way to produce more realistic 3D, without needing tons of memory on the video card. And because it uses the system?s ram, it?s available to the rest of the system when it?s not needed for 3D.

AGP requires new video cards, but also requires changes to the motherboard?s chipset?as a result, users won?t be able to upgrade current systems to AGP. Intel is only planning to add AGP support to Pentium Pro (or Klamath MMX) motherboards such as the 440LX models expected later this year, but it?s expected that other motherboard vendors will be adding AGP support to plain Pentium or Pentium-MMX motherboards later this year. Expect AGP-compatible graphics adapters from most of the usual culprits at about the same time. Cirrus Logic?s Laguna 3D graphics accelerator family will support AGP, for example, and should be widely available at the same time as Intel?s motherboard chipset?the second half of 1997.

AGP will also require operating system-level support. This is also forthcoming. Microsoft has promised AGP support for Windows 95 later this spring, with additions to the Direct Draw programming interface, and to Windows NT 4.0 hoped for later this year. Since this is a hardware change that will only be usable with new machines, don?t be surprised if Microsoft makes these upgrades available only with its OEM release for new hardware?not as a downloadable upgrade for the general public.

Not a 3-letter Acronym: Firewire

Our next new technology lacks a three-letter acronym, so obviously, it didn?t originate with Intel.

Firewire, in fact, was originally developed by Apple, and is also known by the totally unmemorable IEEE 1394. Like USB, it?s an external peripheral bus?a way to attach hardware devices to your computer from the outside. But it?s not really a competitor to USB.

Firewire promises to be about 8 times as fast as USB? 12.5 MBps vs 1.5 MBps, with promised future enhancements going up to a blistering 125 MBps. Like USB, however, Firewire also promises hot-plugging and plug-and-play, and will support peripherals that require electrical power from the system.  But while USB promises the capability to plug in up to 127 devices in a row (compared to SCSI?s seven), Firewire will be limited to a mere (!) 63 devices.

As a super-high performance port, expect Firewire to take longer to catch on than USB, and expect it to cost more, at least at first. The first units will be on PCI adapter cards (Adaptec has already announced such a model), while USB support is already being built-into current motherboards.

But while USB is aimed at keyboards, monitors, scanners, and the like, Firewire will make it possible to connect high-bandwidth devices like camcorders. Users will be able to connect currently-available devices like Sony?s digital camcorder right into their computer?sending digital data without needing to convert from analogue. Look for a new generation of video conferencing devices. Similarly, expect to see new generations of audio and scanning devices lining up for a piece of this bus. In fact, Firewire has the potential of allowing users to connect virtually any consumer electronics device? at Fall 1995 Comdex, Sony demonstrated a prototype Firewire system connected to a whole wall full of audio-video gear.

Even hard disks may eventually come out in high-speed Firewire versions, freed from the hassles of SCSI terminations and device numbers. Of course, all this is dependent on operating system support. While Microsoft has already rolled out a USB driver for its OEM-SR2 version of Windows 95, the best it has done for Firewire is to promise to support it in both Win95 and NT?eventually. Apple has promised Firewire on the motherboard of all its models?desktop and notebook alike, but not until 1998.

While we?ll be seeing hardware and operating system support for AGP and Firewire sometime this year, don?t expect either to be mass-market factors that soon. But start planning for both now; so you?ll be able to anticipate the demand for these products that will be coming down the road a piece.

Next month, new models for memory.

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Alan Zisman is a Vancouver educator, writer, and computer specialist. He can be reached at E-mail Alan