14 Apr
2020
14 Apr
'20
4:54 p.m.
joe mcguckin <joe(a)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.
--
f.anthony.n.finch <dot(a)dotat.at> http://dotat.at/
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