IRHG - Input needed on alternative GC implementations

Dear Core,

   I am just completing chapter 5 of Ruby Hacker Guide
English Version ---  GC - Garbage Collector!

   There was a discussion in old document about possible
Garbage Collector Variations.

   Now, I am not a GC Wiz -- But if any of the core players
who focused on GC implementations would like  to write
a short couple paragraphs on their Favorite GC I will try
to include them in the final document.

  Ideas that may merit exploration are:
          **  Generational GC's
          **  Compaction
          **  Better Memory Mapping (hand roll a new
malloc??)
          **  COPY-ON-WRITE Friendly GC
          **  Other?

  Any contributions would be appreciated and helpful

  Thank You,

         Chuck T.