Wow, they invented the slogan. Sun alumni seem awfully thin-skinned about not getting credit for every little thing they did, which is why it's pretty unforgivable to deny DEC credit for anything more than "some work on hardware". I was working on DECnet-based remote file access software in 1989. It wasn't new, but NFSv2 was. DEC already had real clusters doing real work before Sun did. Within the company there was already a globe-spanning LAT network. I had friends at Apollo who were also way ahead of Sun wrt distributed computing. AT&T's RFS was at least contemporary with NFS, as were Netware and Vines. Sun was definitely a player in that space and made some seminal contributions, but to say they were the first even to think about it is unmitigated BS.
I am not a Sun Microsystems alumni. I wish I was, just as I equally wish I were an SGI alumni.
Yes DEC did have clusters, and I remember booting my Alpha workstations from a Sun SPARCStation 20 over DECNet as an AutoClient and I know DEC had hardware clustering and VMS working together as a distributed system, but since I came at the end of that era and only worked with Ultrix and DECUnix, I don't know any more about it which is why I couldn't go into detail. I only go into detail when I know about something and usually I've done that something myself.