It’s here – IBM Corp, Motorola Inc and Apple Computer Inc have published the first complete version of what used to be called the Common Hardware Reference Platform, but has now been shortened to the PowerPC Platform. Readers with understanding bookshops can pop down the road and order the 300-page tome, published by Morgan Kaufman. The new document is described by Todd Moore, architecture programme manager with IBM’s RS/6000 Division, as being much tighter than the PReP specification that it supersedes: PReP talked much more about recommendations… which lead to confusion. The new system replaces many of these recommendations with mandatory requirements. In addition, the new document specifies a register model for the machine and specifies the way that some registers should be used. So what’s new since the general architecture White Paper was published in April? Moore picks out work done on Open Firmware, a new set of ‘run-time abstraction services,’ and support for multiboot, as particularly noteworthy. The run-time abstracts define a skinny set of application programming interfaces that will help isolate the operating system from differences that manufacturers introduce into their individual implementations of the architecture. Operating systems will be able to rely on these application programming interfaces for standardised power management support, to handle the system clock, PCI configuration, Level 2 cache flushing, error handling and exceptions and a few other things. This is a completely new addition, not present in PReP. On the Open Firmware side, Moore says that the bindings have been more closely specified than previously – defining more exactly how adaptors and boot devices should function. Should there be a problem using existing PCI/OpenFirmware boards in the new machines it shouldn’t be a problem he said, but recommends that manufacturers test them. One big change over PReP is formalised support for booting multiple operating systems.
The design team has completely rewritten the format of the data held in the machine’s non-volatile RAM specifically to enable a choice of multiple operating system boot options. On the subject of how expensive the machines will be to build, Moore is adamant that the additional costs above and beyond PReP are minimal. There is the price of the mandatory ROM socket to take the Macintosh ROM, but other than that he reckons that the additional bits needed to support Mac input-output probably come to around $10 to $12. When will the first machines appear? The standard answer from the PowerPC triumvirate is the second half of 1996, but it is worth remembering that FirePower Systems Inc has been making noises about shipping a machine within 90 days of the thing’s announcement. The company hasn’t been so vocal about this timescale lately, and we couldn’t reach them as we were going to press. However, if the timetable still stands, the first machine would appear on January 11. Make a note in your diary. Another company that should prove quick off the mark is Mac OS licensee Power Computing Corp, which says it has been working on a PowerPC Platform project for the last six months. Apple, IBM and Motorola have announced plans to produce PowerPC Platform-compliant systems along with Canon Inc, DayStar Digital Inc, FirePower Systems Inc, IPC Technologies Inc, Pioneer Electronics Co, Power Computing Corp, Umax Data Systems Ltd and Zenith Data Systems. Apple, IBM and Motorola are developing a certification process for PowerPC Platform-compliant systems. – Chris Rose
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