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UNIX, Mach, and more |
What exactly is Mac OS X ?
Set to appear in the autumn, Mac OS X will look very similar to Mac OS 8, but its underlying software is something else entirely. Where OS 8 was just a cosmetic enhancement, OS X is a rebuild from the ground up. Nothing on your Mac will ever be the same again.
When it first appears, Mac OS X will be aimed at the power user - the Mac devotee who runs the fastest machine with the most RAM to perform the most demanding tasks. It will bring benefits like extraordinary speed for producing graphics and unstoppable sense in robustness in critical systems like Web servers. It will protects your programs, so that others are guaranteed to keep running even if one program crashes. It will support multiple processors running in parallel within your Mac, running your software at breathtaking speed on machines that don't cost the earth. And boy, will it run games as well. Yet, for all that it represents a ground-up rewrite of the Mac OS, this symbol of the future is actually baes on 20-year-old technology, since Mac OS X is derived from the powerful Unix operating system. Unix may be old, but it's fast and it's rock-solid.
What's at the very inside of Mac OS X ?
Mac OS X has at its heart a Unix-based piece of programming code called Mach (no relation to Mac), which controls all the computer's most essential functions. This is the core of the OS, the Mach Kernel. Around this core is a combination of ideas and technology taken both from the Mac OS and from NextStep, the OS created by Steve Jobs's previous company, NeXT Software.
Apple has ensured that the minimum effort will be required to write new code for Mac OS X, using a set of libraries called Carbon.
Carbon? What's Carbon ?
Last year's release of Mac OS 8.5 defined a starting point for many of the operating system changes Apple already has planned for this year. Without at least this version of the operating system, which works only on PowerMacs, you could find your activities increasingly restricted in the future.
The reason for this lies deep within the layers of programming that comprise an operating system, the software that tells your Mac how to behave. Setting out its new agenda last year for the future of the Mac OS, Apple announced it was modifying its original plans to launch a new OS codenamed Rhapsody, and would use the core of Rhapsody to create Mac OS X instead.
The key difference between the two would lie deep beneath the Mac-like surface they shared. Rhapsody worked in an entirely different way from the Mac OS, and this would mean that developers would need to totally rewrite their software to take advantage of Rhapsody's advanced features. None of the big names in Mac software publishing had shown any interest in doing so.
Apple's change of tack involved linking the Mac OS to its Rhapsody technology, so that developers could support a new OS without investing much money in redevelopement. This is exactly what Mac OS X promises.
Essentially, Apple has gone through the key instructions Mac developers use, weeding out redundant commands and implementing new ones, to create a system that would work using just the core software Mac OS X will use to function. Apple has called this revised set of programming commands "Carbon".
The
idea of it is that if a developer makes his program work with
Carbon, it will work on Mac OS X, and most programs require only
a couple of days' work to get them working. It's that simple.
The move to Carbon means that many more programs are likely to
be ready to take advantage of Mac OS X's new features when it
appears this autumn. But a little-published change in Mac OS
8.5 means that it, too, can run Carbon-compatible programs. This
makes little difference to anyone now, but as sales of Mac OS
X take hold, Carbon will become the new yardstick for Mac software
development, so you may find that some future releases, particularly
programs aimed at professional users, won't run on anything earlier
than Mac OS 8.5.
Mac stalwarts like Adobe, Quark and Macromedia have already declared their support for Mac OS X.
Text
taken from: MacFormat 71, February 1999
Picture by me, but based on apple.com info
