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

[Barbara Beeton]

On Mon, 13 May 2013, 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....

i don't think installing a complete new
tex live to get a single file makes sense.
however, if a user has a major project
underway that depends on an earlier version,
that version is >= 5 years old, and the user
is also working on other, newer projects,
then having parallel versions *does* make
sense so that the newer projects can take
advantage of the many changes without
disrupting the "legacy" project.

having spent many hours trying to figure
out and repair files that depended on
particular versions of packages (whether
newer or older than the ones currently in
use for a massive production system), i'm
grateful for the information available
from \ProvidesPackage and the ease with
which this information can thus be
obtained from the originator of a file
simply by requesting the log of the
successful run.

i'm not advocating extreme measures for
"average" users; just in exceptional
cases, of which we encounter more than
one would wish.  (my "favorite" is the
author who, already under contract for
a book, first contacted us with texnical
questions in 2004, still hasn't delivered
the promised manuscript, and turns up
again maybe twice a year with some new
question; surely he's still using his
original installation, and i hope his
computer holds out until he finishes,
so that we don't have to hand-hold him
through a new installation and recovery
of files that surely will not produce
the same results with 10-years-newer
versions of packages.)
						-- bb