CERN Developing For The Macintosh Nubus

YY a CErn -PREeE §9- O10 EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH 9 & SEP. 1989 DEVELOPING FOR THE MACINTOSH NUBUS B.G. Taylor CERN, Geneva, Switzerland CERN LIBRARIES, GENEVA OMAN CM-P00062891 invited paper presented at the EuroBus 89 Conference, London 4 - 6 September 1989 Gq DEVELOPING FOR THE MACINTOSH NUBUS B.G. Taylor EP Division, CERN, 1211 Geneva 23, Switzerland Abstract This paper presents introductory guidelines for European developers of NuBus electronics modules for the Apple Macintosh II family of personal computers. It is based on experience at CERN in developing MacVEE, which interfaces the Macintosh to multi-crate VMEbus and CAMAC systems for data acquisition in large high-energy physics experiments. 1. Introduction While a collaborative truce is being declared by the major open systems bus-war participants, the personal computer market continues to be stimulated by a spirit of lively competition. After navigating quieter waters for over seven years, NuBus emerged into the turbulent mainstream of personal computing with the launch of the Macintosh IT in March 1987. Prior to its adoption by Apple Computer, the bus was little used outside artificial intelligence workstations by Texas Instruments and Lisp Machine. But as the central architecture of Apple’s growing family of ‘Modular Macintosh’ computers, over 250,000 NuBus systems have now been installed worldwide. Apple Europe revenue for 1988 exceeded $1000M, and Europe is now a substantial market for third-party developers of NuBus products. The Apple NuBus is based on minor adaptations of ANSI/IEEE Standard 1196 [1], a concise 70-page specification published in August 1988. This standard is in turn a development of the Texas Instruments NuBus specification [2] first published in 1983, and ‘NuBus’ is a trademark of Texas Instruments Incorporated. The original NuBus was conceived by C. Terman and S. Ward at the Massachusetts Institute of Technology, and was developed by MIT and Western Digital Corporation between 1979 and 1983. NuBus entered the controversial personal computing world just after full 32-bit microprocessors moved into high-volume production, and as the established industry standard architecture based on the PC/AT bus was showing signs of serious fragmentation. Because of Micro Channel licensing restrictions, board size limitations and compatibility issues, different manufacturers chose to follow the patented MCA and open EISA routes in their PS/2 clones. To add to the diversity, IBM themselves introduced an 80286 version of the PS/2 Model 30 based on the older AT-style bus, but for PC-height cards, while confirming that additional MCA enhancements will be introduced in the new 33 MHz Model 75, presumably using undefined reserved lines in the original specification. Since the formation in April 1988 of NuGroup, the association of NuBus manufacturers and users, many organizations have gathered forces around the alternative NuBus architecture 100…