However, most software that requires large amounts of high-speed calculations generally relies on floating-point math. High on this list are graphics programs, especially for CAD and graphic design. The floating-point unit is a separate math coprocessor chip in early 680x0-based machines, but in the 68040 machine, it is an integral part of the main CPU. (A less-expensive version of the 68040 without the integrated floating-point unit-the 68LC040-also is available.) In contrast the floating-point unit not only is an integral part of the PowerPC chip, it is an essential source of its long-term performance potential.

Apple says that for native applications, Power Mac integer operations should be two to four times faster than a Quadra 950 and floating-point operations as much as ten times faster. Therefore, while most programs for Power Mac will initially be simple ports, second-generation software will probably make use of floating-point math for as many jobs as possible to gain maximum use of the PowerPC chip.

Presumably, at this point we'll start seeing products with features that simply are not possible with the 68040 Macs. Right now, the music-software vendors, at least, probably haven't had time to consider the possibilities beyond porting their existing products. Besides, as we'll see, fancy digital-audio tricks might be done better with third-party DSP cards than on the PowerPC CPU. But it seems likely that faster multimedia operations means smoother, more responsive interactivity.

Unsurprisingly, you will need more memory for native-code software. Apple recommends you add at least 4 MB to your current RAM to account for larger applications. Power Macs ship with 8 MB soldered on the motherboard, though, so you have a head start.

The Power Macintosh 7100/66 resembles the Quadra 650 and should appeal to musicians for many of the same reasons: three NuBus slots, scorching speed, a desktop-size case, and a modest list price.

Not So Fast, Buster!
Some kinds of programs, including MIDI applications, have real-time operations that won't necessarily benefit from being written in native PowerPC code. This is true because at this juncture, System 7.1.2 itself is not entirely native. (Presumably, this was done to ensure backward compatibility with existing software.) In particular, the interrupt handler-the code that tells the processor when to stop what it's doing and deal with a higher-priority task-uses the 68LC040 emulator. Whenever there's an interrupt, the PowerPC switches to emulation mode, which takes time; when the priority job is done, the CPU goes back to native mode. This is a system operation, so it occurs regardless of whether the application itself is native.

Operations that call be done in the background without interrupting the processor-such as screen redraws or printing-don't force the processor into emulation mode and can be accelerated dramatically in native code. However, real-time operations, such as reading and writing MIDI bytes, have to be handled immediately, requiring the processor to interrupt its other work, The time required to switch to and from emulation mode to handle the interrupts could mean you wont see it lot of real-time performance improvements from native MIDI programs.

If the MIDI application uses emulation mode all the time, however, there is no switching. Therefore it might be better for real-time music applications to be written in mixed code, with 680x0 code for time-sensitive operations and

Power Windows

One of the long-standing (and overblown) arguments in the computer world pits Mac users against Windows aficionados. We're not quite to the point where everyone can quit fighting, but we're getting closer.

Insignia Solutions has a line of programs that let you run DOS (Soft PC Professional) or Windows (Soft PC with Windows) on a Mac. Unfortunately, even if you have a fast 68030- or 68040-based Mac, it can't exceed 25 MHz 80386SX performance when running applications in Insignia's environment. PC MIDI applications have never been tested.

Insignia Solutions’Äô Soft Windows for the Power Macintosh lets you run DOS and Windows software simultaneously with Mac software, in a separate window. You can transfer data between programs via the Mac clipboard.

With Power Macintosh, some of this, at least, is changing. Insignia Solutions licensed the Windows source code from Microsoft and also struck a deal with Apple. The result is that under Insignia's Soft Windows, Windows 3.1 applications run on a Power Mac 7100/66 as fast as on a 25 MHz 80486SX. When Windows 4.0 comes out, Insignia will have the source code to emulate that, too. You can even run System 7 and Soft Windows simultaneously, in separate windows, and transfer data between them via the clipboard. Estimated list price for the program is $499, and at least 16 MB of RAM is required. The company expects to ship when Apple ships the first Power Mac. In fact, Apple will optionally bundle preinstalled Soft Windows with Power Macs that have 16 MB of RAM or more.

The first version of Soft Windows for Power Mac emulates the 80286, albeit at 80486 speed. Later this year, an 80386/486 emulator is planned that will permit running Windows software in Enhanced mode. PC veterans might notice that hard-drive access is a tad slower, because the Macintosh does more data-integrity checks than a PC when accessing a drive.

Unfortunately, the initial offering won't support digital-audio recording (e.g., Sound Blaster 16 emulation), though it permits PC system beeps. Digital-audio support is also on the 1994 agenda. Insignia still has not tested their environment with MIDI software, but we're pressing them, and they have promised full MIDI tests in the near future. By the way, if MIDI works under Soft Windows, it should work under Insignia's Soft PC programs, too. Stay tuned.

Overall, I got the impression that Insignia is not hip to the relatively small music-software market. But even without MIDI and audio support, Soft Windows lets the Power Mac user run specialized nonmusic programs from the PC world.

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