Date: Tue, 15 Dec 1998 12:41:29 -0000 From: "Scott, Barry [MDN05:7E26:EXCH]" <barry.scott.tsbarry@nortel.co.uk> To: freebsd-isdn@FreeBSD.ORG Subject: RE: streams implementations Message-ID: <81C8165DD2A7D111AD700000F81F29CB025049E7@nwcwi19.europe.nortel.com>
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Jonathan M. Bresler [jmb@FreeBSD.ORG] said. > the idea of streams is wonderful, the realization is costly. each > layer added (or module pushed) slows down processing and hurts > roughput. ritchie developed streams for serial, if i remember > correctly. streams was then applied to networks. there is an RFC > about layering being bad for networking and the relative performance > of NIT vs BPF prove the case. At DEC we used a comms exec called LES (Layered environment services) that allowed a web of nodes to be connected. The VAX PSI and DEC NIS routers and parts of DECnet Phase V where LES implemented comms. LES ran inside the VAX/VMS OS and in embeded systems like the routers. For design and debug LES ran in user mode simulation. The performance was better then direct call between layers. And having clean OO like seperatation of layers and (literally) message passing made implementation fast. Stream (the concept) can be implemented as a very light weight mechanism. Of course we passed buffers around not individual bytes. And used very smart buffer management. BArry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message
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