Path: utzoo!attcan!uunet!decwrl!ucbvax!edinburgh.ac.uk!J.Wexler From: J.Wexler@edinburgh.ac.uk Newsgroups: comp.sys.transputer Subject: H1 (in response to Lindsay Patten's enquiry) Message-ID: <05.Oct.90.10:42:16.bst.330473@EMAS-A> Date: 5 Oct 90 09:42:16 GMT References: <1990Oct2.204634.16609@watserv1.waterloo.edu> Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 69 > Will it really be a 100MIPs, > 100Mb/link processor? > Will those of us who stuck by transputers in the > face of increasingly fast competition be vindicated? 100MIPs: more than 150 claimed, and more than 20 MFLOPS (from tests of early silicon). I think, though, that Inmos are still talking about 100MIPS and 10MFLOPS as realistic speeds for the first generation of these devices that will be marketed. 100Mb/link - Inmos claim 80Mbytes/second total throughput on all four links, which is of the same order as your figure. Vindication: that depends on why you stuck by transputers. It won't be "the fastest chip in the world" in the way that the T800 was (momentarily). It will have slightly better support for operating systems and memory management than the T8, but probably not as much as everybody would like. Inmos refer to this as "an enhanced process model". I doubt whether it will include memory protection and virtual memory support. It will nevertheless be very fast, with a much better balance of processing, transfer and communication-set-up speeds than any other chip, so it will have the edge in large-scale parallelism. It will retain the support for real-time and concurrent systems, still unmatched by other chips. It will still be excellent for embedded systems - but for many such purposes the T2, T4 or T8 will continue to be the best choice, being simpler and cheaper. It will have 16Kbytes of on-chip memory, used by default as a cache but usable directly as RAM if you prefer. The links will not be directly compatible with T-series links (there will be separate chips to interface the two kinds if required). This is because they will offer very important new facilities: multiple channels in each direction supported on a single link (i.e., there will be a firmware multiplexer/demultiplexer), and hardware through-routing so that channels can connect processes on Transputers which are not directly connected. This is achieved by wormhole routing, using a separate chip, which maintains the strict occam model of communication - i.e., termination of transmission implies that the whole message has been received. Thus the typical complement of chips in system using H-series transputers will include Transputers themselves and the new router chips, just as with T-series processors you usually needed C004 switch chips (or equivalent). Single-purpose systems of moderate size may be able to do without the router chips, in the same way that they might not have needed C004s if built with T-transputers. T-to-H link adapter chips are likely to find a lot of uses, (a) in upgrading existing systems, and (b) where it would be wasteful to use H-series chips for all purposes in a system when a T4 or T2 can do many jobs so cheaply. If you just want to use multiple-channels-per-link without through-routing of messages, then the H-series links can do that without any external chips. Personally, I have high hopes of this. As much as anything else, its success depends on Inmos' new openness to giving full support to the languages and systems which potential customers want to use - C and Fortran and so on. John Wexler Edinburgh Parallel Computing Centre _________________________________________________________________________________ Disclaimer: I am not an employee of Inmos, and Inmos has not certified or approved what I have told you. It is fairly old information. It may be inaccurate, misleading, out-of-date, or just plain wrong. I may have remembered some of it wrongly or incompletely. I got it all from (a) published, widely available, sources, and (b) Inmos statements given freely, publicly, and without any request for confidentiality. Neither I nor the University of Edinburgh will be responsible for any use you make of this. No commitment can be assumed for Inmos to deliver any of the specifics that I have described.