1. A shared resource system comprising: a plurality of client computers; at least one provider computer selectively making resource capacity available to said plurality of client computers; and a network connecting said plurality of client computers to said at least one provider computer, said plurality of client computers and said at least one provider computer passing messages to each other over said network, said at least one provider computer sending confirmation qualification messages notifying each client computer requesting resource capacity of any potential conflicts with any portion of the requested capacity.