[tex-live] installing parallel (by year) versions

[Reinhard Kotucha]

On 2013-05-13 at 21:13:40 +0100, David Carlisle wrote:

 > > i stand by what i said.  i'm not keen to advise an "ordinary
 > > user" to maintain a second tree.
 > >
 > > tex's had enough "bad names" in the past ... to encourage people
 > > to believe they need to download a massive object to acquire a
 > > single file ... seems to me to fly in the face of all the hard
 > > work that has been done.  sigh.
 > >
 > > robin
 > >
 > 
 > I'm with Robin here. Not long ago someone on tex.stackexchage was
 > discussing how they'd installed a _virtual machine with a different
 > operating system_ so as to install the latest texlive to get an
 > update to a single package. Several people commented on the thread
 > as if that was a perfectly rational approach. Scary....

Sure, if it's all about a single package, the best solution is to ask
either here or on texhax.  For a normal user it's probably difficult
to get an older release of a package which isn't on CTAN anymore but I
can easily retrieve everything which is not older than 6 or 7 years
from the TeX Live svn repository.  Furthermore, package authors care a
lot about backwards compatibility.  If a newer version of a particular
package doesn't work anymore, then I'm absolutely convinced that the
author appreciates the feedback.  I remember that bugs in packages
shipped with TeX Live were fixed within two or three days.

Robins statement

 > > i'm not keen to advise an "ordinary user" to maintain a second
 > > tree.

is something completely different.  Of course, it's useless to install
an older release as an "ordinary" user without a good reason.  I also
don't recommend to upgrade unless I know that the upgrade solves a
particular problem.  In most cases it doesn't because the user did a
mistake himself.  Upgrading an ancient release makes sense though
because a lot of things are much easier now than in the past, consider
pgflots, for example.

But there is absolutely no reason to *delete* an older TeX Live
release before or after installing a newer one.  TeX Live supports
parallel installations for years and MacTeX even provides a user
interface for switching between them conveniently.

It's not necessary to revert to older releases in most cases but it
never hurts to have them.  I've written many luatex/texlua scripts
which probably don't work anymore with the new Lua-5.2 in TeX Live
2013.  It's not a problem as long as I can run TL-2012 and TL-2013 in
parallel.  It's easier to adapt the code then.  And I'm not in a hurry
because I have something which still works.  I suppose that many
people sleep better if they keep olderer releases, regardless of
whether they ever have to revert to them or not.

Having different versions installed never hurts.  Robin used the word
"to maintain".  Well, one can only maintain the latest release, the
others are frozen anyway.  Hence no extra work needed.

Regards,
  Reinhard
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Reinhard Kotucha                                      Phone: +49-511-3373112
Marschnerstr. 25
D-30167 Hannover                              mailto:reinhard.kotucha at web.de
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