Now that Apple has got the move to PowerPC under its belt, its attention is moving towards a major revamp of the System 7 Macintosh operating system. There is no better way to irritate a Mac aficionado than by declaring that the user interface is looking long in the tooth. In fact many would argue, […]
Now that Apple has got the move to PowerPC under its belt, its attention is moving towards a major revamp of the System 7 Macintosh operating system. There is no better way to irritate a Mac aficionado than by declaring that the user interface is looking long in the tooth. In fact many would argue, with justification, that the Mac Finder can knock Microsoft Corp’s Windows into a cocked hat. However Apple itself has recognised that its operating system can be improved upon and over the past few months has started talking openly about System 7.5, due for launch in the late summer, and two further releases of the operating system, codenamed Copeland and Gershwin, due to make their appearance sometime in 1995 or 1996. The strategy marks the beginning of what will be a major re-vamp for the operating system, perhaps even bigger than the change from System 6 to System 7. Traditionally major releases of the System incorporate aesthetic improvements to the desktop, and these are certainly in evidence in System 7.5. But the changes go much deeper than a graphical user interface facelift. The company also intends, over the next two years, to build a microkernel-based version of the System: one of the jibes occasionally launched at the Macintosh is that, unlike Windows NT, Unix, OS/2 and, soon, Microsoft’s Chicago, it does not support pre-emptive multi-tasking. Pre-emptive multi-tasking enables the operating system to arbitrate between applications competing for the processor.
Memory protection
Each application is forced to hand over control of the machine at pre-set intervals, which means no one program can hog the machine. The Macintosh System, by contrast, relies on ‘co-operative multi-tasking’ in which it is up to developers to ensure that their applications are well-behaved and will relinquish control of the machine at appropriate intervals. Most Macintosh applications these days are well-behaved, but the occasional bad penny still turns up which refuses to drop into the background when asked. The other, linked, problem perceived with the System is its lack of memory protection. There are no absolute barriers to the system memory that an application can tamper with – it is relatively easy, therefore, for an errant program to bring down the full system. It would be an oversimplification to say that a microkernel automatically means pre-emptive multi-tasking and memory protection, but the approach is currently the favourite way to implement them – tuck the core of the operating system out of harm’s way in a package where nothing can interfere with it, and throw everything else applications, extensions, device drivers and the like – out into their own domains where they can harm neither each other nor the operating system. Unfortunately for Apple, such a change cannot be made overnight. Today’s applications expect access to shared memory: without it, many of them would break. So Apple is having to smooth the transition. Details were in short supply at the UK briefing Apple gave, but it seems that Copeland’s architecture will separate the applications from the operating system and Gershwin will implement the architecturally pure version with applications isolated from each other, as well as the System. Mention ‘microkernel’ within the PowerPC community and the question ‘whose microkernel?’ is almost automatically raised. Apple is committed to integrating Taligent object-oriented ‘Frameworks’ into the system at some point. Indeed the company says that OpenDoc will provide a stepping stone to using Taligent technology. Taligent, like IBM’s Workplace OS, uses an IBM-re-engineered version of Carnegie Mellon University’s Mach microkernel.
By Chris Rose
But currently Apple is going its own way: Copeland and Gershwin will use Apple’s own microkernel – the company looked at available offerings such as Mach and found them too bulky, too generic and not sufficiently tailored to the needs of the Macintosh, according to Guerino De Luca, vice-president of marketing at Applesoft. So much for next year and the year after. What is coming in
the rest of 1994? As we have already mentioned, late summer should see the arrival of System 7.5. Currently Apple is indulging in what it describes as the largest beta seed programme in the company’s history. Everyone that attended the worldwide developers’ conference certainly went away clutching a copy. Deep down, System 7.5 is not that different from what has gone before, however the company has really gone to town on the graphical user interface, adding a host of features, some of which originally appeared as third-party Finder extensions, together with much simplified printing, and a truly extraordinary help system. Gone too is Apple’s ill-fated attempt to produce a separate power-user version of the Finder in the shape of Finder-Pro. All the Finder-Pro features are now rolled into a single version, which will be available for both 68000-based and PowerPC Macintoshes. Purists might feel that Apple has gone overboard, throwing every conceivable addition at the elegant simplicity of the Finder, but though the new features are numerous, the brief demonstration we saw suggests they will make the Mac simpler to use for both neophytes and experts. Some of the new features that were demonstrated in the beta: Most recently accessed document or applications. The Apple menu can now contain hierarchical items, two examples are items that record the most recently used documents and the most recently used applications.
Window Blinds. It is now possible to shrink windows so that just their title bars show – useful for those that suffer from cluttered desktops. Simplified Printing. Instead of having to use the Chooser to pick a printer, the Print dialogue presents users with a pop-up menu, from which they can pick the available printers. Printers can also be placed on the desktop as icons it is possible to drag certain documents to the printer to be printed. Portable Digital Documents. Taking a leaf out of Adobe’s Acrobat book, Apple has added a further printer-type portable digital document – printing to this produces a file that can be opened on any other Mac and read, irrespective of whether that machine has the applications or fonts the file was created in. Will portable document readers appear for Windows and Unix? Possible. Improved drag and drop. With properly enabled applications it will be possible to drag elements to be dragged from the desktop straight into documents. PowerTalk mail-enabling middleware included as standard. Every user gets an electronic mail client and unified mailbox. Existing applications are automatically mail-enabled. Mac TCP bundled as standard. AppleScript bundled as standard. This makes it possible to write routines to automate actions, both in the finder and AppleScript-aware applications. Threads Manager included. Threads Manager is one step in changing the way developers write applications – it has been shipping to developers for several months now and enables them to write multi-threaded applications. Next year’s Gershwin version of the System is supposed to implement this, so yes, you will be able to drag things into the waste-basket and copy files at the same time. The new Help system demands a special mention because today’s Balloon Help, lets face it, is awful. Though a system of pop-up explanations sounds a nice idea, in practice no one ever uses Balloon Help’s brief and limited facilities. By comparison, System 7.5 takes context-sensitive help to new heights. It will actually show you how to do things, taking advantage of the scriptable Finder. Say, for example, you want to know how to turn on file sharing. The help system will draw a fat, marker-pen red ring around the Apple menu, indicating that you should select it. If you dither for too long, the menu will open itself with the Control Panel item highlighted in red. And so on, until the task is done. Could be the kind of system to help even the most dedicated compu-phobe. Apple’s plan to re-architect its operating system from the ground up and change the way people think about operating systems is an audacious one, and introducing
memory protection and pre-emptive multi-tasking will be difficult if existing applications are not to break. But in the move from 68000 to PowerPC, Apple accomplished the most masterful transition the industry has ever seen: no one has managed to change processors with as little disruption as Apple. And if it can do it once…
Chris Rose edits PowerPC News, published fortnightly on the Internet and free by mailing add (AT) power.globalnews.com
