http://www.soundonsound.com/sos/1996_articles/feb96/applenotes.htmlALL ABOARD THE PCI BUSS
After last month's look at PDS, SCSI and NuBus, this month's topic is the PCI buss. Here's some questions and answers.
I started to talk about the Peripheral Component Interconnect (PCI) buss in the November 1995 Apple Notes. It provides a platform-independent solution to the problems of producing add-on cards for computers -- which brings us to the obvious question:
Will a PCI card work in my PowerMac?
The answer currently seems to be that provided that a PCI card manufacturer implements the PCI 2.0 specification, complies with the Open Firmware standard (IEEE 1275) for booting PCI cards in an operating system-independent environment, and provides a Mac Operating System-specific driver, then that PCI card should work in a PCI-equipped Macintosh.
If that sounds like quite a few caveats, then the usual advice of 'try before you buy' applies -- and as with any change of technology, test thoroughly in your specific setup, not one that is merely similar to it! Even so, given the wide acceptance of PCI outside of the IBM PC-compatible world, PCI card manufacturers should rapidly catch on to the fact that they have a larger potential market of PowerMac and Workstations like Dec Alphas, and will ensure that they are compatible. Most IBM PC-compatibles already seem to implement PCI 2.0, for example.
What sort of PCI cards will be produced?
Because the PCI buss is intimately connected with the main buss inside the computer, it can provide a number of expansion capabilities that take advantage of the high-speed access that is available. Graphics accelerators and network cards are probably going to be the most common uses, but you can expect some to be Mac-specific, like DOS/Windows compatibility cards with 486 or Pentium processors. Mac music-related cards will include PCI-to-Nubus adapters, as well as PCI-to-SCSI adaptors intended for driving RAID disk arrays. Companies like Digidesign are now producing PCI cards, often with a NuBus-to-PCI exchange scheme.
What about the future of PCI?
In the near future, PCI 2.1 should improve the data transfer speed for some real-time applications -- particularly video editing and perhaps audio direct-to-disk. In the longer term, PCI 3.0 should double the throughput of data to over 200Mbits per second -- but the exact method which will be used to achieve this is still uncertain. The current 33MHz clock could be increased to 66MHz, or the buss could be widened from the current 32 bits to 64 bits. There are pros and cons to each approach, and the PCI 3.0 specification is not due out until 1997 -- so watch this space.
What about 3.3 volt PCI cards?
After many years using 5 volts as the main logic power supply voltage, the ongoing reductions in chip size and power requirements, and increases in speed are forcing the computer industry to lower the supply voltage. 3.3V chips are already being used in many applications: some Pentiums and PowerPC chips use 3.3 or 3.6V supplies, and there are many support chips that use 3.3V. If PCI 3.0 uses a 66MHz clock, then this will force the use of 3.3V. Long-term, the future seems to be 3.3V for almost all computing hardware.
APPLE NEWS IN BRIEF
• IT'S SOUND!
Hidden away in QuickTime 2.1 for Macintosh, the Sound Manager 3.1 System Extension provides enhanced audio recording and playback performance on PowerMacs (see the Opcode news item for suitable models). As well as 'plug-in' architecture for additional third-party audio compression codecs, it also includes two new 16-bit audio compression formats: IMA (Interactive Multimedia Association) 4:1 and µ-Law 2:1 -- which also provides compatibility with WAV and AU format audio files.
• DIGITAL PERFORMER REACHES v1.7
Mark of the Unicorn (MOTU) have a new release of their Digital Performer due very soon. They have produced a CD which showcases some very impressive time-stretching and pitch-shifting capabilities -- well worth an audition. Contact MusicTrack on 01462 733310.
• FREE CD-ROM FROM SYMANTEC!
I was most surprised to receive a free CD-ROM from Symantec recently. They have decided to send out the CD-ROM Subscription free to all registered owners of C++ 8.0. All it requires is for you to fill in and return the subscription card. You then get two updates to the original purchase, and each CD-ROM has updates, new utilities and source code examples.
• GOING NATIVE -- LOGICALLY
Emagic's Logic and Logic Audio v2.5 are now available in native PowerPC form, which should significantly improve performance for PowerMac users. Upgrades (£25: if only all upgrades were this affordable!) can be obtained direct from Sound Technology. Contact 01462 480000.
• NEW VISION FROM OPCODE
Vision 3.0, OMS 2.0 and Galaxy 2.0 for Macintosh have been announced. Vision 3.0 now includes Sound Manager digital audio support for audio waveforms alongside MIDI data, and replaces Studio Vision AV (upgrades are available). Macs with support for Sound Manager digital audio include: Power Macintosh 7100, 8100, 8500, 9500; Quadra 660AV, 840AV; and the PowerBook 520 and 540.
The long-awaited Open Music System 2.0 is now available. Automated studio setup and MIDI instrument detection should make setting up even easier, and there's more use of colour, to make the studio setup easier to understand.
Galaxy 2.0 now supports MIDI Bank Change messages, and the patch linking between Galaxy and Vision has been made more transparent. Contact TSC on 0171 258 3454.
Topic: "all aboard the pci bus" (Feb 1996 article) (Read 3638 times)