In addition to providing raw computer power a distributed processing environment is amenable to incremented design. This inherent design feature means that it is possible to augment existing facilities by ‘simply’ interfacing new resources as and when they become available. Although the revitalisation of existing, ageing, and probably worthless, equipment is very attractive the costs associated with their interconnection are often prohibitive. A design model is presented which aims to minimise these costs by maximising design visibility.