The VAX (officially I think it stood for "Virtual Address eXtension" but those of us who had to program them often said "Virtual Architecture: eXperimental!) was Digital Equipment Corporation's follow-on to the successful PDP-11 line of minicomputers. DEC often referred to is as a "superminicomputer" but it was really no comparison to the real supercomputers of the day like the Cray-1, CDC Cyber 205, Cray X-MP, etc.
The original VAX 11/780 showed up in the late 1970s and it was the first commercial 32-bit computer. It was generally considered capable of executing one million instructions per second (MIPS) and the "VAX MIPS" became a de facto standard against which other computers CPU performance was measured. The "Virtual Address eXtension" bit meant that the VAX had memory management designed to use the disks as an extension to main RAM memory: Virtual memory. Physically a VAX 780 was at least 4 feet wide (more once you add disks, tapes, extra memory, etc.), 5 feet tall, and 3 feet deep. It lived in computer rooms on raised floor tiles.
The original VAX operating system was VMS (Virtual Memory System). It's been said that Dennis Ritchie took all the good stuff from the old (and huge) Multics operating system and created Unix, then Digital took what was left and created VMS. If you liked typing, VMS was a wonderful OS for you. I remember getting a directory listing by typing stuff like "DIRECTORY/FULL SERVER::USER$DISK:[PATH.TO.DESIRED.DIRECTORY.SEPARATED.BY.DOTS]FILENAME.EXTENSION;VERSION" Seriously.
Ken Olsen (founder and CEO of DEC) hated Unix and took every opportunity to trumpet the superiority of VMS. He often used odd measures like the size of the documentation set, proudly stating that the VMS doc set took up over 15 feet of shelf space while with Unix "you only get that one thin manual." He went through a bit of shock and denial when he found out that 1/2 the VAXes going out the door didn't have VMS licenses (and VMS service contracts, and the attendant big revenue for both) included because people were loading Unix on them. Grudgingly he decided that DEC should do their own Unix for the VAX, and "Ultrix" was born. Armando Stettner was the project manager for Ultrix and he hated the name. He told me (yes, I've been around that long) that he thought it sounded like a toothpaste brand. He had a military gas mask that he used to wear whenever he went to meetings with the marketing folks, just to let them know how he felt.
The VAX 780 was followed by the lower cost, lower performance 750 and 730. Then came the higher performance 782 and 785, the MicroVAX line of desktop and deskside systems, and finally the 8000 line. The later (around 1990) VAX 6000 line mixed in the new 64-bit Alpha CPU, so the waters got a bit muddy there.
VMS was eventually renamed OpenVMS to try to convince the masses that a simple name change made it a player in the buzzword-compliant area of "open systems" which was dominated by Sun, Apollo and HP with Unix-based systems. In the 1990s Microsoft was working on a replacement for Windows 3.x and Windows 95 with IBM (actually IBM was doing all the real work, since Microsoft had never actually written anything from scratch) that eventually became OS/2. One of the lead VMS designers left DEC with the source to the new version of VMS he was working on and went to Microsoft. OS/2 quickly got kicked to IBM and Windows NT was born from VMS (again Microsoft wrote nothing from scratch) with the Windows 3.1 GUI sitting on top of it. Later this morphed through a few versions of Windows NT before becoming Windows 2000, then Windows XP, and currently Windows 2003. The Windows 3.x line died, replaced by Windows 95. Win95 got updated to Windows 98, Windows 98 SE, and finally Windows ME (Millenium Edition) before dying off. Some feel that Windows ME was already brain-dead.
So the VAX was a fairly revolutionary and powerful machine in it's day, but it was no supercomputer, despite DEC's marketing efforts. While the VAX was crunching out 1 MIPS (Meaningless Indication of Processor Speed?) as a general-purpose system, real supercomputers of the time focused on floating-point performance and the Cray-1 did 133 peak megaflops (million floating point operations per second) in pre-VAX 1976. During the mid-1980s VAX heyday the Cray X-MP (1982) did 500 megaflops and the the Cray-2 did 1900 (1985) did 1900 megaflops. Quite a performance difference over the VAX, but also a big price differential. The Crays would have made interesting folding machines. Generally they were used by the government for weather simulations and whatever "other stuff" the NSA, CIA, and Department Of Defense did with them.
Now isn't that more than you wanted to know about Mesozoic computing?