Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!usc!alicudi.usc.edu!crum From: crum@alicudi.usc.edu (Gary L. Crum) Newsgroups: comp.sys.next Subject: Re: NeXT Motorola 88K Machine? Message-ID: Date: 12 Jun 91 05:39:11 GMT References: <1991Jun12.031302.13645@leland.Stanford.EDU> Sender: news@usc.edu Distribution: na Organization: University of Southern California Lines: 64 Nntp-Posting-Host: alicudi.usc.edu In-reply-to: melling@cs.psu.edu's message of 12 Jun 91 03:46:33 GMT Originator: crum@alicudi.usc.edu As the InfoWorld article mentioned, an interesting and delicate issue is architecture migration. Sun moved SunOS from Motorola 68k to SPARC architecture and dropped 68k, and SiliconGraphics moved from Motorola 68k to MIPS and dropped 68k. HP is still supporting Motorola 68k while selling HP-PA architecture. Would anyone like to speculate how NeXT might make a transition, given NeXT's interest in the personal computer low-cost shrink-wrapped style? Sounds fun to me... I personally hope that NeXT adds operating system software support for high-performance processors like the 88110 ("Hurricane") while retaining an assumption that the main processor continues to be a Motorola 68k processor (or at least, with the assumption that a 68k processor is always somehow available to execute old applications and so current NeXTstations won't be obsolete soon). So for example, the 88110 chips would be introduced this fall as an optional coprocessor NeXTbus board. Hopefully the price of a NeXT computer with NeXTbus slots, i.e. the NeXTcube or a new computer with NeXTbus slots, will be reduced to be more attractive compared to NeXTstation slabs. In such a scenario, the "hostinfo" command would report that the kernel can support multiple CPUs, and the myraid of processor set control system calls introduced in Release 2.0 would start to be exercised. Given conventions for organizing binaries for different architectures (which the very general Mach object file format supports), the operating system could be setup to use 88110 CPUs if available but revert to using 68k processors if not. That way, NeXT software buyers would need not be concerned about what architecture a given software package requires. The would start to be stickers saying something like "uses 88110 if available". Alas, NeXT didn't do that type of thing with the Intel i860 processor on the NeXTdimension board. (That's not to say that such type of processor support can't be added in a future release.) But, I don't think development tools (e.g. compilers) for i860 processors are as appropriate as current tools for 88k processors when it comes to making a processor available for general purpose use. Once heterogenous multiprocessing support is introduced and functional in NeXT Mach, perhaps 3rd parties would be free to design boards using other processors, and require little operating system change. Lots of processor types are already defined in the NeXT Mach include file /usr/include/sys/machine.h, including i386, MIPS, SPARC, HP-PA, Motorola 88k , but not i860. Those machine type constant definitions were inherited by NeXT Mach from the CMU release of Mach, however. I think that Data General is currently selling a multiprocessor configuration of its Aviion workstations which use the currently available Motorola 88100 processor. I'm not sure what the communication and memory architecture is like, though. I wonder if NeXT can sell a board with two or four 88110 processors on it for less than $5000. As for I/O bottlenecks, I think NeXT Mach (and UNIX systems in general) can nicely support multiple I/O interfaces, such as multiple SCSI interfaces. That's one area where the original Macintosh and MS-DOS specifications fall very short -- they assume that there is a small, fixed numbers of I/O ports (e.g. serial ports) and applications were written to let the user choose only one of those ports (e.g. two or four serial ports). I'm having lots of fun learning things like mpadmin(1), sproc(2) and sysmp(2) on a Silicon Graphics multiprocessor system, and I hope a lot of NeXT users can start doing this type of thing soon. (Is anyone out there using BBN or Encore multiprocessor systems running Mach?) Gary