The Apple News That Got Buried

An anonymous reader writes, "Apple's Showtime event was all well and good, but the big news today was on Anandtech.com. They found that the two dual-core CPUs in the Mac Pro were not only removable, but that they were able to insert two quad-core Clovertown CPUs. OS X recognized all eight cores and it worked fine. Anandtech could not release performance numbers for the new monster, but did report they were unable to max out the CPUs."

Comments

Re: Bash fork bomb

[Anonymous Coward]

http://www.euglug.org/pipermail/euglug/2005-August /004338.html

Cheers!

You know what happens when you make assumptions.

[Gary W. Longsine]

NeXT multiprocessed the guts of OS X on 2-4 processors. The result is that the mach kernel doesn't scale the processors linearly. There isn't the straightline performance boost of adding another processor beyond 4 cores with Mac OS X's mach kernel.

Let's assume for the moment that none of us in this forum actually know anything factual about how many years Apple (or even NeXT before them) have been running Mach on machines with more than 4 processors on the corporate campus behind locked doors.

However, we can probably reason this out if we try. We're all bright geek types, right? There are several clues. NeXT bought Apple for a negative $400 million or so in what, December of 1996?

The heritage of NeXT that you mention is a pretty big clue. I don't recall off the top of my head how many processors were supported by the production shipping Mach build for SPARC and PA-RISC back in the NeXT days, but let's assume it was 2, just for the sake of argument. Both of those platforms offered ready availability of systems with many processors even way back then. Perhaps there were systems like that in the lab.

Mach was originally a research project with an interesting goal: clean support of certain abstractions in a platform-independent way. One of those abstractions was support for multiple processors, beyond the typical SMP architectures we see today, which means that the author's concept of platform-independent went quite some distance beyond a different instruction set in a different risk architecture. Dig this:

Mach kernel
Unlike UNIX, which was developed without regard for multiprocessing, Mach incorporates multiprocessing support throughout. Its multiprocessing support is also exceedingly flexible, ranging from shared memory systems to systems with no memory shared between processors. Mach is designed to run on computer systems ranging from one to thousands of processors. In addition, Mach is easily ported to many varied computer architectures. A key goal of Mach is to be a distributed system capable of functioning on heterogeneous hardware.

That text is unattributed at the Wikipedia page, but comes from this document: Appendix B from the book: Operating System Concepts

An excellent book entirely about Mach is: Programming under Mach, which also mentions the design intent.

The original project was funded by DARPA, with the specific goal of developing operating systems technologies which would support super computers with hundreds or thousands of processors.

The Mach project developed new techniques which have migrated directly (via actual Mach code to OSF, NeXT, Mac OS X, et. al.) or indirectly into pretty much every modern operating system.

Mach research spanned a very long period of time, and two Universities. Curious, bright, and arguably insane people (or they would have been making money instead of slaving away making Mach on grad-student salary) with access to multiple processor machines with DARPA funded directives to make it scale to hundreds of processors. Hmm... that seems like a clue.

NeXT was, and Apple is a hardware engineering company. Apple has been building multiple processor boxes since before the reverse acquisition. I know, I had the, uh, perverse and shameful pleasure of running BeOS on one of them for sport.

If any joker with a web site can get ahold of pre-