Install 4.3BSD Berkeley UNIX with VAX780 SimH Emulator and TCP/IP Networking

by Ramses Soto-Navarro, 7/11/2023

Compile SIMH
Prepare OS Binaries
Inspecting the Dumps
Install the OS
Configure Native Networking
Telnet via Serial Interface
RSH and RCP Login


Welcome, computer historians! Find here brief steps for the install of 4.3 BSD UNIX for VAX780, circa 1986; using the SIMH simulator. This setup is configured with native networking. Other sites demonstrate telnet connections by using the DZ11 emulator for the VAX780 Unibus serial line card. However, here we will use native networking via SIMH’s XU emulator for the VAX780 Unibus DEUNA/DELUA Ethernet controller. In this way, from other terminals on the network, we’ll also be able to connect and upload to 4.3BSD, via FTP. This exercise is significant because it demonstrates what it was like to run and interact with the operating system that first used TCP/IP networking. It is also a good starting point for those that would like to study the origins UNIX, TCP/IP, and other operating systems.

In April of 2006 InformationWeek Magazine declared “The single Greatest Piece of Software Ever, with the broadest impact on the world, was Berkeley UNIX 4.3BSD; representing an unmatched peak of innovation, and the single biggest theoretical undergirder of the Internet. Moreover, the passion that surrounds Linux and open source code is a direct offshoot of the ideas that created BSD: a love for the power of computing and a belief that it should be a freely available extension of man’s intellectual powers–a force that changes his place in the universe.” Find the article here.

Classic original BSD will not run on any x86, including virtual apps such as VirtualBox, KVM or qemu. 4.3BSD was compiled for the DEC PDP and then the DEC VAX line of computers. So, you will need a VAX emulator such as SIMH.


  • Installing 4.3 BSD on SIMH
  • SimH - Installing 4.3BSD on emulated VAX 780

    Without the help from the sites above this document would not be possible. Thank you so much and Stephen’s Machine Room Youtube Channel!

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