Computer Archeology – ULTRIX

Todays exercise we are going to concentrate on the MIPS architecture, particularly on the DECstation 5000/200

If we have no access to the actual hardware, we will use the excellent machine emulator called GXemul which runs quite well (after some tweaks on a modern Linux machine)

GXemul is available here

wget ""

When compiling on Linux via a modern GCC please bear in mind that the emulator wont work correctly if compiled with -O optimization flags. Please use -debug configure option to disable such optimization

$ ./configure --debug

I was building GXemul on Mint 18.2, and had to change the generated Makefile as such in order to build the -X framebuffer support : Edit the GXemul Makefile as such :

XLIB=-L/usr/include/X11 -lX11

Now you can build the emulator via a standard make command.

$ make

Once we have the emulator compiled, lets get the ULTRIX system

Download ultrix-Ultrix-RISC-4.5.img.gz

Gunzip and place to your working directory

Read the howto on

On my Panasonic CF-53 screen is 1366×768 and the GXemul
machine: DECstation 5000/200 (3MAX, KN02) (25.00 MHz) X framebuffer is
1024x864x8 so we need to do this

xrandr --output LVDS1 --rate 60 --mode 1366x768 --fb 1366x1024 --panning 1366x1024

The installation is pretty straight forward  – create an empty disk

dd if=/dev/zero of=rootdisk.img bs=1024 count=1 seek=800000

Run the first stage of install according to


gxemul -X -e 3max -d rootdisk.img -d bc:/path/to/ultrix-Ultrix-RISC-4.5.img  -j vmunix

Run the second stage install

gxemul -X -e 3max -d rootdisk.img -d   c:/path/to/ultrix-Ultrix-RISC-4.5.img  -j vmunix

Boot the final disk image (2x)

gxemul -X -e 3max -d rootdisk.img -j vmunix (2x)

Happy hacking :)


About astr0baby

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