This is a guide for installing NetBSD/vax in the SIMH emulator.

  1. Install Open SIMH, typically from the pkgsrc open-simh package.
  2. Download a NetBSD/vax CD ISO image.
  3. Create a file netbsd-boot-vax containing the following:
            ;set cpu autoboot
            set cpu simhalt
            set cpu 64m
            set cpu idle=netbsd
            attach nvr /path/to/netbsd-vax-nvram.img
            set rq0 ra92
            attach rq0 /path/to/netbsd-vax-hd.img
            set rq1 cdrom
            attach rq1 /path/to/netbsd-vax-cd.iso
            attach xq0 nat:
            boot cpu
  4. Start the emulator:
            simh-vax netbsd-boot-vax
  5. At the VMB prompt, select your preferred language. Set the default boot device, then boot once from the install CD:
            set boot dua0
            boot dua1
  6. Install NetBSD, perhaps omitting X11; SIMH doesn't emulate a frame buffer. (Prior to 6.0, you'll need to change the CD drive from /dev/cd0a to /dev/ra1a when prompted.)
  7. When installation completes, halt the system. SIMH will automatically exit.
  8. At the top of netbsd-boot-vax, uncomment set cpu autoboot. Then restart the emulator:
            simh-vax netbsd-boot-vax
  9. It boots unattended to multiuser. Welcome to NetBSD!

Now consider adjusting your SIMH configuration (download doc):

If you are interested in helping this document cover other NetBSD ports, or have any other comments or suggestions, please contact Lars Brinkhoff <>, or the NetBSD WWW group.


The initial version of this HOW-TO was written by Lars Brinkhoff. Some of the information in this page was derived from an email sent by Mirian Crzig Lennox .

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