| Early next year, you should be able to buy a
PowerPC-based computer that will run Mac software about as
fast as a Quadra 700, Windows software as fast as a 486,
and native Unix software as fast as a Sun SparcStation 10.
The high-speed RISC chips, system software, and
breakthroughs in emulation technology that make this
possible are coalescing under an umbrella known as the
PowerOpen Environment. The ambitious goal of PowerOpen is
to support a scalable PowerPC-based platform that lets
users choose from several different libraries of
applications software running atop the most popular user
interfaces. PowerOpen is a fast-track hybrid: It's an ABI (Application Binary Interface) that is derived from IBM's AIX and optionally includes the X Window System and the Open Software Foundation's OSF/Motif. An optional MAS (Macintosh Application Services) environment provides a Motorola 68040 emulator and a PowerPC version of Apple's Mac OS Toolbox to support Mac applications. PowerOpen promises to run most programs written for IBM RS/6000 workstations and all software written for 680x0-based Macs at near-native speeds. Third-party emulators now under development are expected to run Windows software as fast as a 486. For full-blown performance, PowerOpen will natively host Unix applications from multiple vendors and a new generation of Mac software written especially for PowerPC. The choice of user interfaces will be equally wide. You'll be able to run character-based Unix programs from a traditional command line or launch graphical applications from an OSF/Motif desktop, including the COSE (Common Open Systems Environment) Dashboard. Some people may prefer the Mac Finder or Windows 3.1. Moreover, PowerOpen is designed to let you juggle all these environments simultaneously, even exchanging data between them. Announced in 1991 by IBM, Motorola, and Apple, PowerOpen is in the hands of the PowerOpen Association (Billerica, MA), an independent corporation whose founding members also include Groupe Bull, Thomson-CSF, Harris, and Tadpole Technology. The seven founders are recruiting additional members, who together will promote PowerOpen and guide its future evolution. You won't be able to buy a product called PowerOpen; it's actually a term for compliant operating systems sold by the members of the association. A major goal of PowerOpen is to avoid the binary incompatibility that currently fractures the Unix world. You'll be able to buy a certified PowerOpen application from any software publisher and be sure it will run on your PowerPC-based computer no matter who made the hardware or who wrote the operating system. Developers won't waste time supporting variations of the same platform, and there will be a larger unified market for compliant software. The PowerOpen ABI is subdivided into an API and a KPI (kernel programming interface). The API is a library of routines for applications programmers, and the KPI provides the interface to kernel processes and device drivers. PowerOpen is designed to isolate software from the complexities of device I/O — an important consideration for a platform capable of accommodating I/O buses as varied as ISA, NuBus, Micro Channel architecture, PCI, S-Bus, and VME. At its heart, PowerOpen is a character-based Unix. The OSF/Motif and Mac layers are extensions that vendors can optionally include with their PowerOpen operating system. PowerOpen's window manager, built on X, supports both OSF/Motif for graphical Unix applications and the Mac GUI. Because the COSE Dashboard runs atop OSF/Motif, it offers yet another option. You can use the Mac Finder for systemwide file management, because even non-Mac files will appear as icons on the Mac desktop. To run a Mac program under PowerOpen, you first launch a System 7 session that executes within an X window. Because the Mac session runs in an independent X window, it can coexist with other X windows running other tasks. The X clipboard lets you cut and paste between different sessions. As with any X window, you can resize or move the Mac session around the screen. In every respect, it's a fully functional System 7 environment with its own local multitasking, so you can run several Mac programs simultaneously. Mac programs will multitask cooperatively within their session, because Apple's System 7 doesn't yet support preemptive multitasking. But PowerOpen does support preemptive multitasking, so independent Mac and Unix sessions can preempt each other to win processor cycles. Even though the PowerPC and the 680x0-series chips' instruction sets are incompatible, existing Mac applications will nevertheless spend most of their time running natively on the PowerPC — thanks to the MAS architecture. The MAS is Apple's key contribution to the PowerOpen alliance. For the first time, Apple has agreed to license its proprietary Mac OS Toolbox to rival vendors — in this case, for use in their PowerOpen operating systems. In May, PowerOpen was shown running Mac applications and a QuickTime movie on three workstations: an IBM RS/6000, a Sun SparcStation, and a Hewlett-Packard series 720. The MAS isn't just for backward compatibility, however. It also supports a new generation of Mac software that has been written or ported to run natively on PowerPC. Several major developers — including Microsoft, Quark, Aldus, Adobe Systems, Frame Technology, and WordPerfect — have already announced they will move their applications to the new platform. If PowerOpen delivers on its promises, it will achieve the Holy Grail of hardware independence — high-performance compatibility with the world's most popular software on a single platform. Supported Industry Standards— AT&T's Base System V Interface Definition— BSD 4.3 — Posix (portable operating system for computer environments) — TCP/IP networking — X/Open Portability Guide, issue 4 (XPG4) — X Window System version 11, release 5 — Open Software Foundation's DCE (Distributed Computing Environment) and DME (Distributed Management Environment) may be adopted in the future Illustration: PowerOpen-compliant operating systems are built on a character-based Unix foundation derived from IBM's AIX. A common ABI ensures that any PowerOpen application will run on any PowerOpen operating system. OSF/Motif and the MAS are optional extensions. The MAS includes a native Toolbox and a 68040 emulator that support existing 680x0-based Mac applications, and a new generation of PowerPC-based Mac applications. Tom R. Halfhill is a BYTE senior news editor. You can reach him on BIX as "thalfhill." Copyright 1994-1997 BYTE |