Comment by SassyGrapefruit

>You've never been at a company that finds it needs to upgrade from $old_version_control_sytem to $newer_version_control_system?

I've done this maybe a dozen times. Its always been big bang and I've never lost any history I didn't choose to lose. In fact I just did this last week for a 10 year old project that moved from SVN to GIT.

If you work somewhere where someone tells you this isn't possible consider finding a new job or alternatively become their new source control lord with your new found powers. Moving things between SCM systems is about the easiest thing you can do. Its all sequentially structured and verifiable. The tools just work everytime.