[gclist] gcfaq cleanup

[David Chase]

Hello all,

I am on vacation, and feeling guilty for my lackluster maintenance
and editing of the faq.  I won't be able to update the official copy
until John Levine returns from vacation, but I can make the edits
now.

In particular, I am behind on correcting addresses for contributors,
and there have been some (published) advances in GC algorithms.
Some that I know of are:

1) concurrent card mark processing (someone at Sun does this)

2) elision of redundant card marks between safe points (Sun and
    NaturalBridge do this, at least).

3) Bacon's (?) reference counting improvements (per-thread
    cache of inc/dec operations, periodically processed)

4) a way of implementing copy-on-write where the old contents
    of a cell are stored in a per-thread buffer, are thus the
    "copy" for purposes of a snapshot.  I don't know the reference,
    but I think it was someone in France.

How much else is worthwhile?

David Chase