As part of performance improvements introduced in Management Server 10.1 FR2, the machines and discoveredmachines tables have been reconciled into a single table.
Previous to 10.1 FR2 the Management Center database contained two tables for storing machine information, DiscoveredMachines and Machines. These tables are often the subject of a SQL join in several Views and Stored Procedures, they often contained one record each per managed end-point. In order to improve performance, these two tables have been reconciled into a single table (called Machines). All existing attributes from both tables have been merged and the attribute IsDeployed has been added to differentiate between between records representing discovered machines and machines.