[lug] Quote of the Day

[Sean Reifschneider]

On Tue, Jan 30, 2001 at 04:14:13PM -0700, D. Stimits wrote:
>because unix doesn't thread right, that the threads were just forks. I
>guess he didn't understand the implications of a connectionless protocol
>like http, and it sounded good.

HTTP is connectionless?!?  How do you mean?  It uses TCP...  Do you mean
stateless?

People say "threaded" like it's an inherently good thing.  You get a
different perspective on this when you program Java where you have to
everything with threads...

Threads are another way of handling multiple things happening in a
program.  Other ways are forking with IPC and select/poll
multiplexing.  The Apache API actually does have the ability to
do threading in it's lower-level platform-independent code, but
that's not the way it goes for Unix.

Apache pre-forks processes and keeps a pool of processes that are
ready to handle an incoming event.  If no fork is required on incoming
connections, it doesn't matter if you're doing a heavy-weight process
or light-weight thread as far as latency.

You can implement the algorithms in any of these ways, it just depends
on what you're most comfortable with and what fits the job best.  For
example, I implemented a multi-plexed SMTP sink which was blazingly
fast.

However, forking does have one kind of nice advantage.  If the process
handling a connection dies or freaks out for some reason, it doesn't
impact any other connections or the server overall.  Not necessarily
true with threads or multiplexing.

Perhaps threads are contributing to the instability IIS?  (The one client
we have using IIS found their http server would just die about once a
week).

Sean
-- 
 "I want to see more of you around the lab."  "Fine.  I'll gain weight."
                 -- Chris Knight, _Real_Genius_
Sean Reifschneider, Inimitably Superfluous <jafo at tummy.com>
tummy.com - Linux Consulting since 1995. Qmail, KRUD, Firewalls, Python