[plt-scheme] Continuations

Hi

I am a new joinee on this list, and recently I have been looking at
continuations implementation in PLTScheme. I have a few questions and
any help and answers would be greatly appreciated. The questions are-

1. Does PLTScheme use a C stack or a stack of its own for scheme
programs, specifically for continuations (saving and resumption
thereof) ?

2. Lets say I have a particular program running in two instances of
PLTScheme runtime (R1 and R2). I am looking to advice and conceptual
issues associated with an attempt to serialize a continuation in R1
and later deserialize in R2 and invoke it.

Some issues related to (2) that I'm aware of are related to what I
refer to as "connectors to world", i.e. file descriptors, sockets etc.
But lets forget them for a while, and for a start concentrate on
conceptual/holistic issues related to the task.

Hoping for replies

Sincerely
- Akhilesh