Lisp Machines started at MIT, some of that code is actually available online now (http://www.heeltoe.com/retro/mit/mit_cadr_lmss.html). That software became the basis of two companies: Symbolics and then later, Lisp Machines Inc (LMI). This Wikipedia entry does a good job at explaining the impact this part of history had on RMS: http://en.wikipedia.org/wiki/Lisp_Machines#Folklore_about_LM...
So, here is where the history of Genera is non-existent or murky. Yes, you can download a torrent of Genera. But how do you obtain a legal license Genera? Who actually owns the IP to Genera?
In learning the answers to those questions, I was left with even more respect for RMS and an amusing, if not ironic, anecdote showing how his vision for the future turned out to be correct.
> How do you obtain a legal license Genera?
You purchase a copy of Open Genera for the DEC Alpha for $5000 from David Schmidt.
> Who actually owns the IP to Genera?
John Mallery (http://www.csail.mit.edu/user/926). He's the most recent owner. Before he got the IP, it was owned by a series of law firms and ex-Symbolics employees.
Why do I find this this amusing? Well, the software that RMS worked so hard to protect and that ultimately helped "inspire" him to start GNU has been relegated to the footnotes of history. Meanwhile, GNU software is used on millions of machines.