[tex-live] Installing TeX live on MacOS X

[Richard Koch]

Angelo,

You installed with the TeX Live install script rather than MacTeX, but
maybe an explanation from the viewpoint of MacTeX would help explain this.

When we constructed the 64 bit binaries for the Mac, we did some 
benchmarking. The benchmarks showed that the 32 bit binaries were
very fast and there wasn't a great need for 64 bit versions.

We used that fact to argue that if we were to provide 64 bit binaries, those
binaries should be compiled on Apple's latest system, currently Snow Leopard
and possibly Lion in future years. However, we couldn't add those binaries to the
universal-binaries which contain both PPC and Intel code because if we 
did, Leopard 64 bit systems would select them and then crash.

So the TeX Live install script always selects 32 bit binaries for the Mac,
although it allows you to add 64 bit binaries as well if you want. I argue
that this is the correct behavior because the 32 bit binaries are very fast.
The alternative is to add complicated code to the install script which determines
the users operating system. Then that code would have to be modified in the
future as Apple introduces more systems, and it would be difficult to maintain
but make virtually no difference for users.

In MacTeX, we always install both binary directories (these directories are
small, 32 megs compared to 1.5 gigs of TeX stuff). But we add an extra
Preference Panel which selects the active binary, and that Pane contains
the logic to select 64 bit versions only on Snow Leopard and above. The
result is that the people in TUG with the difficult task of dealing with the
whole system working on all possible architectures don't have to worry about this
picky detail, and the Mac folks can keep their small piece of it up to date.

Dick Koch