Re: [TUHS] STREAMS performance

[Tony Finch <dot@dotat.at>]

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joe mcguckin <joe@via.net> wrote:
>
> I seem to remember that Sun was trying to sell boxes to the airline /
> reservation industry, and one of the ways they came up with to make
> Solaris handle thousands of ascii terminals was to push the character
> discipline code into streams in order to eliminate the multiple
> user/kernel crossings per character being handled…

I encountered this feature when deploying some new Solaris 2.5.1 / 2.6 web
servers in about 1997/8. We were chroot()ing the user login daemons
(telnet and ftp) to improve security, and they wouldn't work on a freshly
rebooted server. Eventually I worked out that telnetd loaded a kernel
module on demand, and this didn't work when it was chroot()ed, but telnetd
could skip it if the module had previously been loaded. (I could see from
truss and/or strings that telnetd was specifying an absolute path to the
module rather than expecting the kernel to know where to find it.) I was
kind of impressed by the performance engineering, and it stuck in my
memory because it took me so long to understand why it sometimes didn't
work...

Tony.
-- 
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