[TUHS] Mach for i386 / Mt Xinu or other

Noel Chiappa jnc at mercury.lcs.mit.edu
Wed Feb 22 02:25:30 AEST 2017


    > From: Diomidis Spinelli

    > Arguably, the same can also be claimed for the networking system calls.

Well, it depends on exactly what you mean by "networking system calls". If
you mean networking a la BSD, perhaps.

However, I can state (from personal experience :-) that the I/O architecture
circa V6/V7 was not very suitable for TCP/IP internetworking (with its
emphasis on an un-reliable network, and smart endpoints). The reason is that
such networking doesn't really fit well into the 'start one I/O operation and
then block the process until it completes' model.

Yes, if you have an application running on top of a reliable stream, you
might be able to coerce that into the 'uni-directional, blocking' I/O model
(if the reliable stream implementation is in, or routed through, the kernel),
but lots of other thing don't work so well. (Think, e.g. an interface with
asynchronous, un-predictable, RPC calls in both directions.)

	Noel


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