In CI No 2,415, we noted that IBM Corp is so far known to be working on two personalities for its Mach microkernel-based Workplace OS – the OS/2 personality and the MS-DOS/Windows personality. Combined, these two produce OS/2 for PowerPC. At the heart of the MS-DOS/Windows side sits an Instruction Set Translator, which converts iAPX-86 instructions into PowerPC code on the fly. In principle, IBM’s Instruction Set Translator is similar to that used in Insignia Solution Ltd’s SoftWindows, detecting code loops and storing them in a cache so that they have to be translated only once. However, while IBM declines to give details, the noises coming out of its emulation labs sound very gung-ho. To date, the best description of IBM’s emulation approach, comes not from IBM itself, but from the April edition of Byte magazine.

Bizarrely

An excellent article by Tom Halfhill suggests that IBM’s Instruction Set Translator performs an initial discovery pass of the iAPX-86 binary code, to construct a directed graph that represents the application’s flow of execution. This means that the program can be split into basic blocks, which are then translated. The range of optimisation techniques that the article outlines is impressive and the writer quotes IBM as saying that the emulation delivers the performance of a full 33MHz 80486 on a PowerPC 601 processor. Unfortunately, it neglects to mention at what PowerPC clock speed this was achieved. As previously reported (CI No 2,390), the Instruction Set Translator is bizarrely not available to the actual OS/2 module, so your existing OS/2 for iAPX-86 applications will need to be recompiled for the new processor. In addition to the Instruction Set Translator, IBM continues to take advantage of its rights to the Windows source code up to release 3.1 – the last release to which it has such rights. The company has taken this source and compiled a number of the applications programming interfaces into native PowerPC code. How long it can maintain this approach, as Microsoft’s Windows code diverges from 16-bit Windows 3.1 towards 32-bit Windows 4 (Chicago) remains to be seen. An alternative approach to running Windows might be to use the Wabi technology from Sun Microsystems Inc’s Sunsoft unit. IBM’s AIX division is taking this tack, but Wabi currently lacks breadth of application support and Giangarra was dismissive of its abilities: We in the OS/2 world do not believe that Wabi will support enough Windows applications he says, adding I personally don’t have that much faith in Wabi’s ability to provide a good Windows facility for OS/2 users. As for other personalities, an AIX module is also planned to appear at some unspecified time in the future. It is not seen as a priority since the IBM Unix will run quite happily on the Power Personal machines when they first appear. The biggest question that seems to be in a lot of users’ minds is will I be able to run Macintosh software on IBM Power Personal machines? To be more precise, it is a question that is interesting a lot of Mac users at the moment. The answer is no, at least not under Workplace OS.

By Chris Rose

IBM says that there is no development going on to produce a Macintosh personality for WorkPlace OS. The slightly longer answer is yes, you will be able to run Macintosh software, but only under the forthcoming PowerOpen-compliant version of AIX, which is due in the second half of the year. This will include support for Macintosh Application Services. IBM has made it clear that people should not hold their breath waiting for an Macintosh System 7 personality. Which leaves Taligent. Taligent, originally a joint venture between Apple and IBM, but now with Hewlett-Packard Co added, would make a feature in its own right. It was originally conceived as a project to build a top-to-bottom object-oriented operating system, but the focus has gradually changed, until now the emphasis is on producing a rich set of object-based developers tools and frameworks. A framework is a large grouping of objects, which together form the basis of a simp

le application-ette. A framework could be a graphing engine, a text editor or a file-system. Developers can take frameworks and customise them accreting their own objects, or customising those supplied. IBM’s plan is to gradually pull Taligent technology into WorkPlace OS in an evolutionary way. Eventually Taligent may exist as the full operating system it was intended to be, but in the meantime Taligent parts will be added to the OS/2 Personality where it will enhance features such as the graphical user interface. At the same time, other bits of Taligent will appear as Personality Neutral Services, adding object extensions to any other operating systems hosted by Workplace OS. The biggest unknown about OS/2 for PowerPC and Workplace OS is when it will appear. Generally, IBM is simply saying that it will be in the second half of this year, and some observers suspect that this means the fourth quarter. In fact the schedule seems to be slipping. As we went to press, an IBM minion acknowledged that the finished product may not appear until the beginning of 1995. It may appear in beta test this summer however.

Half-cocked

IBM also says WorkPlace OS will appear in beta test form with the first of the Reference Platform-compliant PowerPC machines when they appear in the second half. No wonder IBM is so keen on getting Windows NT converted over. Without the Microsoft Corp offering, the only finished operating system available would be AIX. Even with NT, however, the first Power Personal systems will lack the finished Human-Centric interface that is so important to the division’s success. The sight of IBM and Motorola Inc paying for the privilege of converting NT to the PowerPC chip has enraged some OS/2 aficionados – a particularly lively debate is under way on the CompuServe PowerPC Forum at the moment. However, IBM is caught in a cleft stick. It cannot afford to rush the operating system out and have it go off half-cocked. That was the fate of the first incarnations of OS/2, and IBM has learned its lesson. WorkPlace OS has the potential to be an excellent and innovative operating system, but one false move at the start could kill it. Neither is AIX the kind of operating system that will capture the hearts and monds of the vast majority of personal computer buyers. So, Power Personal is left with NT as a stop-gap. However, if Workplace OS is as good as IBM says it is, it should have the potential to blow NT away on the client machines: We aim to raise the bar on what people expect from a personal computer says Giangarra, and it is a bar that could do with some raising.