My Computer Collection
MicroVAX 3100M30

Photo of MicroVAX 3100M30
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The MicroVAX 3100M30 is among the first machines of the 3100 series. The CVAX processor chip is the slower 90ns version, resulting in a performance of roughly 3 VAX-Mips, as the model name already tells :-). The case is the typical BA42 case Digital used for a lot of DECstations, VAXen and even external SCSI boxes. It is a 'headless' machine, i.e. it has neither a video card nor keyboard or mouse interface. The two serial ports freed by this are used as standard serial ports, to attach e.g. terminals or serial printers, so in theory you can attach 4 VT100 terminals to the machine in theory (though that wouldn't be too much fun with today's software...). Since there is no video on the main board, the SCSI host adapters sitting on a daughtercard in VAXstation machines could be moved to the main board. The machine however still has a daughterboard carrying the internal SCSI connector and some other strange-looking things I have no ideas about. Maybe it's in conjunction with the DB50 and 36-pin Centronics connectors. I have heard there were machine variants with an additional MFM hard disk controller, which might explain the DB50 connector, since this connector was also used on the VS2000 for the second hard drive.

Rear photo of MicroVAX 3100M30
Click here or onto the photo for a full size version of this picture.

DEC CVAX, 11.1111 MHz
at least L1, size unknown
Integer Performance:
3.0 VAX-Mips, roughly like a 386/16
16 Mbytes (options range from 4M to ...)
Interfaces (onboard):
  • 4 x Serial
  • 1(2?) x SCSI (narrow)
  • 10 Mbps Ethernet (AUI+BNC)
Add-on cards:
busless machine, apart from graphics board
Operating System(s):
  • NetBSD 1.3 + patches

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©1999 Alfred Arnold,