Option Effort Comment ------ ------ ------- Free, unregulated None (directly) Indirect cost - need more machines, potential for frustration Free, regulate by Fairly small dev., Access control by reserving machines moderate support Hesiod group for classes to set acl's Free, regulate by Moderate to large, Probable high maintenance dynamically lowering high maintenance cost, due to need to priority for heavy refine sched. algorithm users for fairness Free, usage subject Moderate sched. dev Strict quota highly to quota inflexible, adding flexibility is more work Strict per-hour Small to moderate, charge, otherwise depending on what unregulated is required to export records to billing system Charge flat rate, Moderate Allowing different subject to quota or changing quotas is somewhat harder Charge varying rate, Moderate based on time and/or priority Vary charge depending Large, high Complex, potential to on system load maintenance annoy people Allow multiple Moderate to large, Potential for confusion accounts depending on how and/or irritation at having accounts data can be to specify an account/group. imported/exported Any of the schemes requiring the scheduler to access usage data (e.g. dynamic priority or charge rate, quota, etc.) would be made significantly more complex by going to a multiple master model.