William F. Hammond writes:
 > In practice *today* only Lamport LaTeX has a chance of being viewed
 > as portable.  LaTeX2E appears to lack a wide enough distribution at
 > this point.
grrrrrr.

*LaTeX* is as described in Lamport's book, of which only the 2nd edition
can be bought now. That describes LaTeX2e, ie standard LaTeX. The older
LaTeX209 is deprecated, unsupported, etc etc.

 > Portability aside my guess is that, as a theoretical matter, there
 > exist no _fully_ _automatic_ _failsafe_ _translations_ from legal
 > Lamport LaTeX to _any_ format that is not DVI or constructible from
depends on the target DTD. systems like TeX4ht, VTeX, and Omega, which
use TeX as their translation engine, cannot fail if you make the
target relaxed enough

sebastian