VAXes were 32-bit computer systems from Digital Equipment Corporation (or DEC). They enjoyed huge popularity throughout the 1980's and early 1990's. The VAX was the 32 bit computer that the ancestors of modern UNIXes were made on, and was the standard computer architecture (like the IBM PC is now) of its day. The VAX was also one of the major testbeds for the early Internet.
VAXes come in several shapes and sizes, ranging from the small room sized VAX 11/780 (1970's) through to the desktop sized microVAXes and VAXStations of the 1990's. The VAX architecture and Digital's VAX/VMS operating system are mutually intertwined, so for a review of VAXes see
The VAX Archive
VMS 20th anniversary special
No. The DECstations use the MIPS processor, and have names like
These use the R3000 or similar MIPS CPU. Many of the peripherals are similar to those found in later model VAXstations, but they are not the same.
These were a stopgap for a few years while DEC developed what would become the Alpha processor. I've got one, but I'm not an expert on them, so please don't ask us questions about them.
The DECstations ran ULTRIX/Mips as the only offering from DEC. They never ran VMS. If you have one of these, you can also run;
The following Operating Systems run on a VAX;
The VAX system line has been discontinued, so DEC, now owned by Compaq, no longer sell them. However, occasionally systems for sale do come up on EBay and other on line auction houses. Also look out for companies "upgrading" their VAXes to something more newfangled. Occasionally port-vax (The NetBSD mailing list) or linux-vax (our mailing list) will have notices of VAXes up for grabs.
Practically speaking, for the 3100 series, a keyboard, a mouse, a monitor, and the little switch in the back in the other position. VAXstations were designed for graphical work, and tended to come with better graphics cards. VAXservers just sat there, and used a terminal as the console.
For more information about such details see, for example, The VAX archive