Re: continuations in the real world?

["Paul Q.Graham" <address@hidden>]

It depends on the granularity at which you divide stuff
over multiple machines.  At Viaweb each user was sent
to a given machine after logging in, and for the rest of
their session talked to that machine.  When you have numbers
of users/machine in the hundreds or thousands (and you 
have a weird application if the numbers are lower) the
sample size is large enough to dwarf variations in loads
between users.  --pg

--Mario Latendresse wrote:
> 
> Avi Bryant <avi@beta4.com> writes:
> 
> > session state.  For those who use it, even (especially?) those who know
> > nothing about continuations, it's not just of academic interest to be able
> > to layer normal control flow over the HTTP request/response loop and get
> > transparent backtracking to boot.  I know from personal experience that
> > the use of continuations has a profound simplifying effect on the
> > architecture of large web applications, and from what I'm hearing from
> > early users of the framework, they're discovering the same thing -
> > smalltalkers may not be used to dealing with full continuations, but they
> > know good magic when they see it.
> 
> If you scale an application over several machines, the use of
> continuations require a distributed implementation of the underlying
> runtime system. Without such a distributed implementation, which is
> the current state for all functional implementations I am aware of,
> this lack of scalability is a major problem. May be you have a
> different solution or indeed such a distributed runtime system?
> 
> Mario