扩展了ISO 8571第2部分中给出的虚拟文件存储抽象模型的定义，该模型用于描述文件和文件存储、可用于操作该模型元素的操作集，以及单个文件和关联的属性，以纳入重叠访问的概念。引入重叠访问的目的是，当单个启动器需要执行许多读取和更新操作时，可以更高效地访问结构化文件。

Extends the definitions given in ISO 8571 part 2 for an abstract model of the virtual filestore for describing files and filestores, sets of actions that may be used to manipulate the elements of this model, and the properties of individual files and associations to incorporate the concepts of overlapped access. The objective in introducing overlapped access is to allow more efficient access to structured files when a single initiator has a need to perform many reading and updating operations.