At this month's MacWorld Expo in San Francisco, Apple finally unveiled its new Mac Operating System strategy based on the December 20 acquisition of Next, and its NextStep/OpenStep OS.
Apple will develop and ship both the current Mac OS (System 7) and the new Mac OS 8 in parallel. Apple will deliver four more releases of System 7:
System 7.6, code-named Harmony, is a minor upgrade to the current System 7.5 and will ship by the end of this month.
In July, Apple plans to ship Tempo, which will probably be called System 7.7. That OS will include the first fully PowerPC-native Finder, the Java Virtual Machine for Macintosh to run Java programs, support for multithreading in the Finder, and a more 3-D-looking interface.
In early 1998, Apple will ship the Allegra update to System 7, probably calling it System 7.8.
And in mid-1998, Apple expects to release the Sonata update to System 7, probably calling it System 7.9.
Meanwhile, Apple will also be developing the Next-based Mac OS, which has the code name Rhapsody. Apple expects to offer developers the first version of Rhapsody in the third quarter of this year, with the first general release to the public around January 1998, and the first release that is Mac-program compatible in mid- to late-1998.
Apple expects to support both System 7 and the new Mac OS for several years, even after Rhapsody ships to the public.
The game plan for the next OS
Apple plans on developing a compatibility box for the Next-based OS that will let it run most System 7 programs. The so-called Blue Box is not hardware but a Window within the OS in which any System 7 program that doesn't communicate directly with the hardware should run. The programs would include system extensions and control panels, but not drivers, and some utilities that do work directly with the hardware. This level of compatibility is more than was planned for Apple's original Mac OS 8 effort, known as Copland. That OS would not have run extensions and control panels.
According to IDG sources, the Blue Box will be bug-for-bug compatible with System 7, so programs patched to work around bugs in the current OS will not need to be modified to run in the Blue Box compatibility window. That also means that technologies such as QuickDraw 3D, QuickTime, OpenDoc, QuickDraw GX, and the DayStar multiprocessing API will be supported in the Blue Box environment. The Blue Box will not be a Mac emulator but the actual System 7 OS running on the new Mac OS microkernel, the part of the OS that manages the hardware and basic system operations.
But the new Mac OS is the Yellow Box, or in other words, the Mac OS 8 to be based on the recently acquired NextStep OS's OpenStep version. Unlike Copland, Yellow Box will be fully pre-emptive, multithreaded, and have full mem-ory protection. This means that programs can work in parallel without causing each other to crash if something goes wrong.
It also means that users should be able to run several tasks in parallel, such as faxing while printing, or doing a database sort while reading e-mail. Under the Copland plan that Apple killed in August, only some parts of Mac OS 8 would have had these capabilities.
Rhapsody's Yellow Box will also support fully symmetrical multiprocessing, in which any available CPU can run any program or program thread. System 7's multiprocessing architecture reserves one CPU as the traffic cop, which divides the tasks of programs specifically written for multiprocessing among the available CPUs. The primary CPU is less available for task sharing because of its role as traffic cop.
Apple plans to rework the NextStep OS's interface so it is Mac-like. While Apple will adopt some NextStep conventions, the company is convinced that the Mac OS's human interface is the best available and wants to ensure that this approach is maintained. Within the Next-based OS, Apple will hide the remnants of its Unix command-line interface.
Like the abortive Copland effort, the Next-based Mac OS, in the Yellow Box window, will support multiple looks. Thus, you will be able to customise the interface's visual appearance and how some of its features operate, such as preventing network access for some users.
Programs running in the Blue Box will be able to share some data with programs running in the Yellow Box, and vice versa. According to IDG's sources, programs in the two environments can share data via Apple events (Apple's OS-based messaging technology) and via copy and paste. However, direct interapplication communications probably won't be allowed, so the two environments can't cause each other to crash if something goes wrong in one of the boxes. Not yet clear is how users and programs will be able to deal with files created by programs running in the two environments. While the hope is to let both Yellow Box and Blue Box programs access each other's drives and folders, it is too early in the Rhapsody development effort for Apple to know whether, or how, it can accomplish that goal, at least in the 1998 releases.
Under Apple's new OS plan, Rhapsody will work on all currently shipping PowerPC-based Macs from Apple and the licensed Apple clone makers (DayStar Digital, Motorola Computer Group, Power Computing, Umax Computer, and, in Japan, Pioneer Electronics) and their sublicensees.
Apple has also committed to supporting all future Macs, including systems based on the Common Hardware Reference Platform architecture developed by IBM and Motorola. Apple says the CHRP design should become available to licensees later this year and will spur the interest of even more Mac clone makers.
Apple is exploring support for previous Power Macs, such as those using the NuBus peripheral bus, but is making no commitments, IDG's sources say.
Apple will continue to support and sell the Intel x86 and Sun Sparc versions of the NextStep OS, but its main focus will be on the Macintosh development.