I posted the following (in shorter form) in another thread, but seems to me it deserves its own topic here since some of us do long-distance collaboration (and many of the rest of us are interested in it for obvious reasons):
Take a look at "Unison" file synchronization software
This file synchronization software is quite different from PDM software. There is no checking out files and checking them back in, but it seems to perform SOME of the important functions that PDM software does. It compares different versions of the same filename, not merely on the basis of the date/time of the last edit on the file, but also by comparing file contents. If a conflict arises that the software cannot resolve by the "rules" you set up for it to follow, then someone has to manually resolve the conflict and decide which file is the "good" one, or reconcile by combining differences manually. At any rate in this manner it doesn't just automatically overwrite files, and it does better than just asking you if you're sure you want to overwrite a file with an older or newer version. I'm pretty sure it can also take into account the difference between time zones in comparing file dates and times, and if computers at both ends of the line have time automatically adjusted via one of the many online methods available then at least comparative times will be accurate. These kinds of software can automatically or semi-automatically maintain sychronization between two different sites and most can apparently do it at specific times in the day, or specific time intervals during the day, or upon demand. This synchronization can be BI-directional, which could mean that Toolbox files, Palatte Part files and Template files (etc) can remain current between both sites. You're PROBABLY able to exclude bi-directionality for specific files or directories that require administrative priviledge to change. One nice thing about such software is that it typically optimizes bandwidth use by using sophisticated algorithms -- sometimes even editing not-currently-in-use-files in real time to transfer only the differences between files -- so that so that you're not always having to wait while huge file transfers are occurring.
I don't know whether Availl or Unison or any of the other similar softwares function as well as touted. Even if they do everything as they say and as easily as they say, they surely don't entirely prevent problems from occurring, but they may do well enough to prevent much time being consumed in the process and may prevent ALMOST all problems from occurring. A little process design and planning might pretty well prevent disastrous errors from occurring at all, but of course there's never any guarantee. For that matter, though, somebody can always do something thoughtless while sitting in a cubicle on-site that could yield results as bad as anything one can do remotely, and even PDM software isn't idiot proof. It's hard to make that argument to a client in another city, however. Most won't buy it, and for probable good reason.
If anyone has had experience with Unison in particular or any of the other file synchronization applications out there in general I hope they'll post something about their experiences.
Mark 'Sporky' Stapleton Watermark Design Charlotte, North Carolina