master copy

名词 master copy:

1. an original creation (i.e., an audio recording) from which copies can be made
   同义词：master, original

1. It controls how data and database are shared among users on the network and how users access master copies of data and application software on the centralized hard disk.
   它控制着网上用户如何共享数据和数据库，以及用户如何存取中央硬盘上的数据和应用软件的主拷备。