1. A method of updating a processing system, said processing system comprising a plurality of computing resource units wherein at least two of said resource units are initially allocated to a first application, and wherein said processing system has insufficient resources to simultaneously run both of said first application and a second application at full capacity, said method comprising: de-allocating fewer than all of said resource units allocated to said first application; then allocating at least one resource unit to said second application; and then de-allocating at least one resource unit from said first application.