Apple Starts to Fill in the Blanks
by Steven Noble
from the February 1997 issue of Australian MacUser magazine
Apple computer has bought NeXT Software, and is going to use that company’s high-performance operating system (OS) NeXTstep as the basis of the next major revision of the Mac OS - code-named Rhapsody. This is good news, because NeXTstep has many of the features that bring speed, stability and strength to next-generation operating systems, including protected memory, preemptive multitasking, and a modern virtual memory system.
So what will this hybrid OS be like, and how will its development affect the Mac OS 7.x that all of us use and some of us love? Apple is starting to fill in the blanks, albeit slowly, and has posted a list of frequently asked questions at http://macos.apple.corn/macos/releases/rhapsody
Here’s how things look at writing:
The heart of the system
The heart of any OS is its ‘kernel’, which handles ’low level’ tasks such as utilising the processor. NeXTstep uses the Mach kernel, as do several versions of the stable-but-sinister OS called Unix. This has contributed to the portability of NeXTstep, which was first bundled with machines that used the 680x0 processors found in older Macs (not Power Macs) and then rechristened ‘OPENSTEP/Mach’ and · ported to run on Intel and Sparc processors.
At writing, Apple was still not committing itself on the kernel front, saying only that “Apple will be using a modern microkernel as the foundation of Rhapsody, designed to provide preemptive multitasking, protected memory, and other modern operating system capabilities. Apple will provide more specifics on kernel capabilities in early 1997.”
Mach is one obvious contender for kernel-of-Rhapsody status, as is NuKernel, which was created by the Copland team. As Mach and OPENSTEP/Mach already run on PCs and some workstations, analysts have openly wondered whether Rhapsody may one day do the same. At writing, Apple is saying that it will continue to support OPENSTEP/Mach on multiple hardware platforms, and that Rhapsody will support Power Macs and the PowerPC Platform (PPCP). All other kinds of hardware - PCs, workstations, older ‘040-based Macs, and Macs with PowerPC upgrade cards - may or may not be supported by the new OS. We await further announcements.
Seen on the screen
NeXTstep uses Adobe’s Display PostScript to draw shapes (characters, lines, dots) onscreen; the Mac OS currently uses QuickDraw, and Apple has developed its own high performance alternative, QuickDraw GX. QuickDraw GX would have been the cheaper but “Apple intends to adopt the PostScript imaging model for Rhapsody.” The upshot? Expect what you see (on your monitor) to be closer to what you get (when you print to a PostScript laser printer). And hope that the company brings the functionality of ColorSync, QuickDraw GX and other best-of-breed Mac OS graphics technologies to the new operating system. At writing, such “technical details . . . are still under investigation,” but ColorSync should be ported to Rhapsody.
The look and feel
Those who complain about the Mac OS complain about crashes and the like. Those who praise it love its interface: the Trash can, the File menu, the folders and windows and scroll bars. Knowing that this interface is the source of many users’ loyalty to Apple, the company has declared that “Rhapsody’s user interface will combine elements from both the Mac OS and NeXTstep, but will be closer in look and feel to the Mac OS Finder.” In other words, expect Command-Q to still mean Quit.
Preserving value
Feeling like the Mac OS is one thing, running Mac OS software is another. Most programs that run under System 7.x will run under Rhapsody in an environment called the ‘Blue Box’ (see diagram). Apple is emphatic that this ‘Blue Box’ will not be an emulation environment; it will be native Mac OS code. To the user, this Mac OS environment will appear as a window on the Rhapsody desktop - a window that can be blown up to fill the entire screen, looking like the current Mac OS. Some software will ‘break’ with Rhapsody - mostly ’low level’ stuff that might try to do things that Rhapsody itself is taking care of - and need to be rewritten to work in the new environment.
For those who can’t or won’t upgrade to the new OS, Apple will continue to upgrade Mac OS 7.x in six-monthly increments, and will continue to support that environment for years to come.