[RC5] Pluggable client modules...

Wilson, Bruce bwilson at fers.com
Mon Dec 6 13:52:51 EST 1999

Hash: SHA1

|-----Original Message-----
|Hello all,
|I was wondering how difficult it would be to implement a client which
|automatically updated itself.
|Maybe it could determine whether or not there is a newer 
|version available
|(from one of the key servers , or another proxy, using a 
|similar method to
|determine when new contests start..?), and if so, switch over 
|to that newer
|version. It would make things a lot easier if , say , you had 
|a few hundred
|clients installed.

Quite difficult, actually.  Have you ever tried replacing dnetc.exe (or
rc5des.exe) while the client was running?  Can't be done, and even if
it could, you'd still have to stop and restart the client for the new
version to take effect.

Let's say you do think of a way to copy the file while it was in use
(such as copying it to a new filename, stopping, renaming files, and
restarting).  If you stop the client, what application is going to
perform the renames, and cause the client to start again?  Sounds like
you'd need a second application on each client machine to supervise the
upgrade.  This is technically possible, but it adds some complexity to
the system.  Ignoring the security risks (which are significant), how
do you write such a thing so it is portable across Win32, Mac, Solaris,
Netware, Un*x, Win 3.1/DOS, OS/2?  What happens when the upgrade fails?

Finally, even if you could get all that working, how do you upgrade the
upgrade application when a new version comes out?

I think the idea suggested elsewhere about notification is the best
approach.  Rumor has it a future version of the client will allow
plug-in type addons.  This might also include querying the
client-version (so you can find the machines that need an upgrade), and
requesting a shutdown.

Nugget and Decibel and I have talked about the possibility of sending
an e-mail to participants who still have one or more clients on an
older version (probably only if you were dangerously out of date).  The
e-mail could list the problem version, the IP address, and whatever
other identifying information might be useful to you.  This is still in
the "wouldn't it be nice if..." stage.  Any comments?

Bruce Wilson, Manager, FERS
bwilson at fers.com, 312.245.1750, http://www.fers.com
PGP KeyID: 5430B995

"Give me ambiguity or give me something else."

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