Configuring DIMMWIT Computers

This note outlines how to configure the computers needed to run DIMMWIT. It is possible to use one of two private network configurations.

Two-computer private network

The original DIMMWIT configuration, consisting of two computers:

The two computers are linked by a cross-over ethernet cable (to avoid the need for a hub). This can be a long (50ft) cable to allow remote operation.

Three-computer private network

This more complicated setup allows the observer to analyse DIMMWIT data while other data is being recorded.

The two-computer (laptop and ICE) private network described above is no good for this because mouse events (even motion) are transmitted via the X protocol from the machine displaying finder to the machine running finder, causing dropouts in the data.

One solution that is relatively simple and cheap to implement is to have a three-computer private network, using a switched hub.

The names and roles of these three computers are as follows:

The three computers are each linked to the same switched ethernet hub by a standard non-cross-over ethernet cable. A switched hub is needed to ensure that dimmwit does not see X events due to the observer analysing the data. The cable from dimmwit to the hub can be a long (50ft) one to allow remote operation.

Setting up dimmwit

Under construction.

Setting up dimmwithost

These notes are very brief for now. However, they should be sufficient if you are an experienced Linux sysadmin.


Private networking

Install software

NFS server

Ensure that portmap access is enabled in /etc/hosts.allow:

portmap: LOCAL, 10.0.100., 192.168.20.

Make sure that there are no entries in /etc/hosts.deny that would stop NFS working. For the same reason, disable any firewall running on dimmwithost (iptables/ipchains).

Samba server


ssh key-pairs


With both dimmwit and dimmwithost connected to the private network, and the CCD camera connected and powered up:

Setting up dimmsum

Under construction.

DIMMWIT Resources

John Young <jsy1001 (at)>
Last modified: Mon May 10 18:06:40 BST 2004