User manual

Linux

Like other recent versions of SIMH, VAX MP also supports TAP and VDE interfaces. VDE option requires

VDE libraries installed. For more information on building SIMH images with VDE refer to appropriate

general SIMH documentation (file

0readme_ethernet.txt).

In order to access network interfaces VAX MP needs Linux capabilities (privileges) CAP_NET_RAW and

CAP_NET_ADMIN. To be able to run VAX MP with networking option using account other than root,

these capabilities have to be assigned to VAX MP executable fle itself. To assign these capabilities to VAX

MP executable file, first make sure you have

setcap command available by installing packages

libcap2 and libcap2-bin, for example:

sudo apt-get install libcap2

sudo apt-get install libcap2-bin

Then grant required capabilities to VAX MP executable:

sudo setcap cap_net_raw,cap_net_admin=eip /path/vax_mp

VAX MP (and, more generally, SIMH) networking can be configured under Linux either as dual-homed or

as bridged setup. Bridged setup is most usual under Linux and will be explained in detail in this section,

however it is also possible to configure dual-homed setup or setup that uses only one interface linking

VAX instance either to remote nodes only (via NIC) or only to the host machine itself (via TAP interface).

Network connection between VAX MP and host machine requires the use of TAP/TUN devices. For

bridged setup, TAP devices are bridged with physical network interface. First make sure you have pre-

requisite packages installed:

apt-get install bridge-utils

apt-get install uml-utilities

Make sure you also have gawk installed. Type gawk at the shell prompt and if the shell displays a

message that

gawk is not installed, then install the package suggested by shell.

Ensure you have default route defined. Issue command

route -n and look for entry 0.0.0.0 (last line in

the example below). If you do not have default route defined on your system, define it before

proceeding.

$ route -n

Kernel IP routing table

Destination Gateway Genmask Flags Metric Ref Use Iface

192.168.21.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0

0.0.0.0 192.168.21.2 0.0.0.0 UG 100 0 0 eth0

Also see Jordi Guillaumes i Pons, “SIMH 3.9 – Using VDE for fun and flexibility”,

http://ancientbits.blogspot.com.es/2012/06/simh-39-using-vde-for-fun-and.html