MUMPS compiler/interpreter preservation

I don't know how many of you fine people are familiar with the MUMPS programming language, but MUMPS development accounts for about 50% of my income. Considering that it has as storied of a background as UNIX (having been first implemented in ~1966), and is old, I'm wondering if any of you have any thoughts about it. Also, I'm wondering if any private collections have any older MUMPS implementations around, not necessarily so that I can try to get them, but so that I can find out if they've been preserved. Since InterSystems bought out Digital Standard MUMPS, as well as contemporaries from Micronetics and DataTree, these old implementations seem rare and hard to find. I've long wanted to get ahold of a VAX-based MUMPS implementation, but the closest thing I've ever found is an installed copy of DSM for Alpha on a cluster I picked up, with no media. Any thoughts or information? jpw