While Unix International and the Open Software Foundation are locked in a dogfight for ultimate control of the Unix skies, the groundswell of Unix system and software development continues unabated on terra firma. As they bid to establish their respective microprocessor architectures as the most popular amongst the Unix fraternity – and grab maximum market share along the way – the RISC chip developers are fighting tooth and nail to ensure there is as much compatibility between systems built around their processor architectures via ambitious software projects. One means of achieving much of this in one go is to develop an ABI – Application Binary Interface – a set of rules for hardware and software builders to follow when developing for a specified CPU and its operating system. Most of the major Unix system manufacturers have now committed themselves to developing computers based on one or other of the various RISC processors. The contenders are Intel’s 80860 and 80960, MIPS Computer Systems’ R Series, Motorola’s 88000, Sun Microsystems’ Sparc, Hewlett’s Precision Architecture, Intergraph’s Clipper, Advanced Micro Devices’ Am29000 and IBM’s new Power.

Sparc International

Many of the RISC designs are second-sourced to other semiconductor vendors for fabrication but it is Intel, MIPS, Motorola and Sun that are currently slugging it out to get their designs established as market leaders. Sun and ICL have already developed an ABI for systems built on Sun’s Sparc processor running Unix V.4, and Sun is moving its SunOS Unix operating system – which still contains many BSD features – towards full compliance with the AT&T version. As a bridge between the widely used SunOS version 4.0.3 and Unix V.4, the company releases SunOS 4.1 in April. This version is source code-compatible with System V.4 – so applications written on SunOS 4.1 for System V.4 only require recompilation on a System V.4-based computer to run. It is also binary compatible with SunOS 4.0.3, meaning all SunOS 4.0.3-based applications will run under SunOS 4.1 without modification. A future version of SunOS will be fully compliant with Unix V.4, though Sun isn’t prepared to put a timescale on it. Meanwhile Sun’s supporters club Sparc International, which incorporates Sparc processor, system and software developers, has been quietly revamping its operation over the last few months, and at last month’s UniForum show positioned itself at the centre of the Sparc community by licensing Sparc technology from Sun as well as taking over the Sparc trademark and logo. With this the club takes on the testing and branding of Sparc-compliant systems and software via the Sparc Compliance Definition, Version 1 of which is based on SunOS 4.0.3 and is out later this year. Version 2 will be based on Unix V.4 and the Sparc ABI, but will have to wait until there is a fully V.4-compliant version of SunOS. Furthermore, while Sun retains ownership of the Sparc itself, Sparc International is now charged with the task of directing the technical evolution of the chip, much as Unix International is plotting the course for Unix to follow while actual development is left up to AT&T’s Unix Software Operation. –

By William Fellows

There are estimated to be 1,500 applications currently available for Sparc systems, and over 100,000 Sparc microprocessor sets have shipped, of which there are presently 10 versions announced, ranging from an 18MHz CMOS part to an 80MHz ECL implementation. Former Fujitsu employee Greg Leonard becomes the consortium’s executive director. Motorola has chosen a similar course for its 88000 RISC processor – it has a supporters club called the 88open consortium – although the company retains overall control of both the microprocessor architecture and its future direction. 88open has opted to develop an 88000 Binary Compatibility Standard – more or less the same as an ABI, but at a lower level – covering single and multi-processing 88000 systems with Unix V.4-based operating software, and has opened several testing centres where system and software developers can go to

get their products evaluated. One is in San Jose, California; in Europe they are located at Data General’s offices in Frankfurt, West Germany; in Oslo, Norway at Norsk Data’s Dolphin subsidiary and at Motorola’s own offices in Maidenhead, Berkshire. System manufacturers that have, or are currently, developing 88000 machines include Motorola itself, Data General, Tektronix, Unisys, Sanyo Electric, NCR and Opus Systems. Currently only Opus Systems has 88open-certified hardware, however Tektronix and Data General are said to be close with their systems, and Motorola is a little further off. 88open also has a specific software project called the Software Initiative, which brings together all software houses developing for the part – it reckons there are over 200 members of the initiative, and 100 applications now available. Intel currently has two RISC offerings, the 80860 and 80960, but no formal supporters club. An ABI for the 80860 running Unix V.4 has been developed by Intel – the company is responsible for all processor development and evolution, as well as the testing of system and software compliance. The 80860 ABI has effectively been rolled into the PAX – Parallel Architecture Extension – standard that Intel and Alliant have been developing for single, parallel and multi-processor 80860-based systems. It combines the ABI with an Application Programming Interface – API – and compiler and graphics technology, and there are reckoned to be at least 50 software companies now working on compliant products.

Embeddded systems

Apart from Alliant, 80860 system developers include Altos, Stardent, Stratus, Olivetti, Meiko, Real World Graphics, Tadpole and Multiflow. Intel is also working on an ABI for multi-processor 80386, 80486 and 80860 systems based on Unix System V.4 in conjunction with AT&T and Olivetti among others, but the late arrival of System V.4 has delayed the project, says to Intel. The 80960 doesn’t really fit into the systems picture: it lacks a memory manager and is aimed specifically at embedded systems. MIPS Computer Systems’ R Series of RISC processors has been taken up by a host of major Unix players – DEC, Nixdorf, Sony, Bull, NEC and Pyramid among them – its ABI for the chips running Unix System V.4 is being developed in conjunction with AT&T and is on track for April delivery. However there are a couple of headaches that have yet to be completely cured. Firstly byte-ordering changes DEC has made in its implementation of the processor on the Ultrix-based DECstations has caused problems for developers, and shrink-wrapped software that results from the ABI will not be delivered into the hands of DECstation users because Ultrix is incompatible with Unix System V.4. To try and circumvent the problem a MIPS Application Interface has been developed that will provide source code compatibility for software on any R-series machine via a set of specifications for compilers and user interfaces. MIPS customers can already get advance copies of the finished Interface, but it will not be published in the public domain until the ABI is completed; the two will then be distributed together.