Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!ames!lll-winken!uunet!mcvax!ukc!warwick!inmos!wraxall!roger From: roger@wraxall.inmos.co.uk (Roger Shepherd) Newsgroups: comp.arch Subject: Re: Message queues Message-ID: <1446@brwa.inmos.co.uk> Date: 9 May 89 09:01:15 GMT References: <279@inmos.co.uk> Sender: news@inmos.co.uk Reply-To: roger@inmos.co.uk (Roger Shepherd) Organization: INMOS Limited, Bristol, UK. Lines: 36 In article <5668@inmos.co.uk (Michael Winser) writes: >In article <279@inmos.co.uk (Jim Hutchison) writes: >>Has anyone seen/heard of an architecture which aided kernel message passing by >>supplying hardware message queues for *fast* message queueing and dequeueing? > >The transputer, I believe. > Well, no actually. The transputer does have fast mesage passing and scheduling but is has NO message queues. The model of message passing implemented is that of CSP, processes synchronise when they pass messages; if the receiver is not ready to receieve when the sender sends, the sender suspends. If the sender is not ready when the receiver wants to receive the receiever suspends. This model is supported, not only for processes running on the same transputer, but also for processes running on distinct transputers joined by trasputer links. The choice of synchronised message passing has many advantages both to the implementor and to the user. One advantage is that it eliminates the need for message queues (and hence message buffers) to be associated with every communication channel. If another style of message passing is required it can normally built from the process and message passing primitives in the machine. A fuller discussion of the issues here can be found in Communicating process architecture INMOS Ltd Pub: Prentice Hall ISBN 0-13-629320-4 Roger Shepherd, INMOS Ltd JANET: roger@uk.co.inmos 1000 Aztec West UUCP: ukc!inmos!roger or uunet!inmos-c!roger Almondsbury INTERNET: @col.hp.com:roger@inmos-c +44 454 616616 ROW: roger@inmos.co.uk