My new VAXstation

I’ve known about this website for a while but although the author had made some (considerable) progress enhancing the VAX simulations in ‘simh‘ until a few months ago there was no code available to run on Linux.

When I noticed that the source code for ‘simh’ has been updated and now included simulations for the VAXstation I and II, I decided that at some point I was going to have to try it out, even though I had been quite successful in using my Linux PC with DEC windows.

Today I finally got around to it. Why – because I can…!

Getting Started

First you will need to download and compile the current version of ‘simh’, then if you want to be able to access the network from your simulated VAXstaton you will need to configure the tun/tap network interfaces.

Note – You will need to compile ‘simh’ with SDL support to be able to use the emulated video.

Configure SIMH

When starting the simulation you will need to tell it what devices are configured and several other options, the most important in this case being the cpu model.

; vaxstation.cfg
;-- Load CPU microcode and attach non-volatile RAM
load -r ka630.bin ; Modified firmware to emulate a MicroVAX II.
attach nvr vaxstation.bin
;-- Set MAC address and attach Ethernet to a network interface
;   to eth0 (If using DECnet the MAC address should be set to
;   match the DECnet address).
set xq mac=AA-00-04-00-10-32
attach xq tap:tap0 ; Assuming tun/tap used.
;-- Attach defined drives to local files
set rq0 rd54
attach rq0 vax$station.dsk ; Boot disk
set rq3 cdrom
attach -r rq3 vax$vms.iso ; Installation media
;-- Disable unused devices. It's also possible to disable individual
;   devices, using a construction like "set rq2 disable" if desired.
set dz lines=4 
;set xq disable ; If not using the network.
set rl disable 
set ts disable 
set tq disable ; Tape drives
set rq1 disable
set rq2 disable
;-- Select HALT operation
set cpu conhalt ; Retuern control to VAX console.
;set cpu simhalt ; Return control to simh
;-- Set console port and break character (used to return control 
;   to simulator).
set console notelnet, wru=10 ; Ctrl-P to exit, do not use telnet
;-- Set CPU parmeters and boot.
;set cpu autoboot
set cpu idle=vms
set cpu 16m ; Must be not more than 16 megabytes
set cpu model=vaxstation ; The important bit!
boot cpu
; Exit the simulator.

Starting SIMH

To start ‘simh’ all you need to do is invoke the simulator and pass it the name of the configuration file.

$ microvax2 vaxstation.cfg

The simulator will then start and (unless you uncommented the autoboot entry in the config file) wait for you to enter the console command to boot the system.
VAXStation-II-DECwindows-001If you have already installed VMS and enabled DECwindows then after a while you should see a familiar login screen..

VAXStation-II-DECwindows-002Unfortunately the display is only black and white (that gray window border in the screenshot below is achieved by using a pattern). In the future I hope ‘simh’ will be able to simulate the GPX colour graphics display on a VAXstation 3100 Model 76, but for now I’m very happy as I can now run my Xwindows code natively on a ‘real’ VAXstation.

VAXStation-II-DECwindows-004And of course VMS always was Y2K compliant!

This entry was posted in Linux, Retrocomputing, VMS and tagged , , . Bookmark the permalink.

2 Responses to My new VAXstation

  1. Matt Henrysditch says:

    Hi, What are you display settings in VMS to display DECwindows image in simh? I see only mouse pointer in my emulator if I try to start ex. decwclock…

    • mike632t says:

      If you are using the local display then you don’t set the display settings in VMS explicitly, the operating system determines the resolution, colour depth and so on based on the hardware installed – which in the case of simh is a VCB01 (QVSS).
      Are you sure DEC windows started – by default the screen background should be grey as in my screen-shot, not black. If I remember correctly there is a logical in systartup that needs to be set to true for DEC windows to start but I’m not sure what the default is.
      Unless you are using the system account on a fresh install in might be worth checking that the system/account are you using have the necessary privileges and quotas?
      If it is a fresh install did you run autogen after you installed DEC windows?

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