| 摘要 |
In a word processing system storing a text stream on a direct access storage device (DASD) for recall and editing, the text stream is organized into a document, which is stored on the DASD as a data set. The data set consists of an index portion and a portion containing text records. The index portion is divided into nodes, of which the primary node is called the root node. A volume which refers to the full contents of the DASD can be formatted to contain multiple zones, each of which is logically independent of all other zones, when the contents of a storage volume can be divided conceptually into portions the uses of which are logically independent. Each zone has its own media allocation map, and data sets whose root is allocated within a given zone have all allocations within that same zone. If more than one data set with a given data set type exists on the storage volume, all of those data sets and the data set director for that data set type are allocated within a single zone. For each zone, a recovery required indicator is provided so that zones not requiring recovery need not be scanned when volume recovery is being performed. When only one zone is being recovered, the logical sector number of the root node referenced by the index element in the anchor is used to determine whether or not the data set lies in the zone being recovered, and to skip data sets that do not lie in the zone. |
