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From Andrew Finkenstadt <kah...@icon-stl.net>
Subject Re: Apache 2.0 ideas
Date Tue, 03 Nov 1998 06:55:42 GMT
On further reflection and after reading the "Halloween Document" (
http://www.tuxedo.org/~esr/halloween.html ) and Microsoft's alleged desire to
more tightly integrate IIS into the kernel, ...

(yes, it's been a long evening of thinking)

if you posit the presence of a large pool of shared memory between processes
of varying flavors (kernel-space and user-space) and the existence of a fast
semaphore capability in the underlying kernel to gate access to critical
segments of that shared memory (which is essentially how Windows NT operates),

then you can gain the zero memory copy capability very easily, by leaving the
various chunks of your data in the pool of shared memory, and sending them
directly from kernel space with a write-multi type system call aka message.

Yes, it would leave behind many flavors of Unix that don't have good support
for shared memory, but it would beat the pants out of Microsoft.

We should take a page from Oracle's book on semaphores and enqueues, by making
the critical sections as small as possible, and as fine-grained as possible,
allowing multiple processes access to the data without road-blocking.

-andy





Andrew Finkenstadt wrote:
> a strong message passing
> architecture (similar to the apache request_rec but designed to minimize
> expensive memory-to-memory copies) would probably suffice to avoid multiple
> independent processes like could be used elsewhere, or the monolithic
> single-threaded (unix) process of LISTSERV.
>

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