Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!apple!oracle!news From: csimmons@jewel.oracle.com (Charles Simmons) Newsgroups: comp.arch Subject: Re: Does anyone know anything about the N-Cubed Hypercube? Message-ID: <1990Jun2.113908.13662@oracle.com> Date: 2 Jun 90 11:39:08 GMT References: <1990May23.172140.17510@portia.Stanford.EDU> Sender: news@oracle.com Reply-To: csimmons@oracle.com Organization: Oracle Corp Lines: 61 In article <1990May23.172140.17510@portia.Stanford.EDU>, dhinds@portia.Stanford.EDU (David Hinds) writes: > From: dhinds@portia.Stanford.EDU (David Hinds) > Subject: Does anyone know anything about the N-Cubed Hypercube? > Date: 23 May 90 17:21:40 GMT > > > It seems that a corporate sponsor is going to give my lab access to > an "N-Cubed Hypercube" for computational biochemistry studies. I don't > know much about the machine - it is supposed to be based on Intel 432-like > processors, with 16MB of memory each, and up to 8192 CPU's. The model we > are getting will have only (!) 32. Does anyone have any experience with > these machines? It seems that it would be difficult to parallelize code to > make good use of a fully-distributed memory system like this. How do the > processors communicate? > > -David Hinds > dhinds@portia.stanford.edu David -- Seeing as how my current favorite piece of hardware is an NCube, allow me to correct a few of your small pieces of mis-information (if they haven't been corrected already). The name of the company is NCube. Although the principal designer of the processor worked for Intel back in the days of the 432, the NCube processor looks a lot like a Vax, and has nothing in common with the 432. 16 general purpose registers, each 64-bits long, can hold either an integer or floating point value. IEEE floating point. There is also a PC and SP register. User and Supervisor states. No paging. There are 4 segments. Addressing modes: register direct, register indirect, immediate, predecrement, postincrement, offset+register, offset+register indirect, indexed, direct, and a couple of others. Each chip has 14 on-board communications channels. Each channel is two wires wide -- one input and one output. 13 of these channels are used to create the hypercube -- thus the limitation on 8192 nodes. The 14th channel is used to connect to one or more I/O nodes (in a fashion that I don't really understand). The communications hardware uses wormhole routing and seems to be quite efficient. I haven't had to carefully position my processes on the 'cube to get efficient communications. I disagree that it is difficult to make use of the distributed memory. I do believe that it requires coming up with a good model for how you want to break up an algorithm. Our current machine also has 32 nodes, each with 16 MB of memory. There may be a couple of things you'ld like to pick up from us. We have ported GCC (the GNU C compiler) to act as a cross compiler from a Sun to the 'cube. Our GCC compiler is, in my opinion, about 30-50% faster than the compiler you will get from NCube. We do fun little things like pass arguments in registers. I've also got some fun Mandelbrot software that you might want to have lying around. The compute portion runs on the 'cube, using a color Sun terminal running X as its output device. -- Chuck