Ok, I'm making myself a COMPAT_10 kernel and will try to stop asking
stupid questions for a while.

before I do pipe down, can I beg for a short description of which (if any)
of the COMPAT_* flags in a kernel config file are worth keeping these days?

COMPAT_9 might well be bogus...
COMPAT_43 is probably still useful
COMPAT_BSDI I need for running some multicast code

I have also yet to understand why I might want IBSC. Is the acronym decoded
anywhere or is a stab-in-the-dark (b)inary (s)co (c)ompatibility it?

-George