> I got a CD-ROM just now and am able to install NetBSD from CD. Ok,
> I boot from the NetBSD alpha CD, it seems fine, but finally it stops
> at the point with a line: SWITCHING TO SERIAL CONSOLE. What shall
> I do now? What's the meaning of serial console?
> 
> My machine is a DEC3000/500.

Sounds like your framebuffer/video card is not supported.  It wants you to
use a TERMINAL for a console.  Get a terminal, or terminal program running
on another computer, set it to 9600 and 8n1 and plug it in to your alpha's
MMJ or serial port via Null-Modem cable.