Patent attributes
A storage control system manages a utilization of data blocks of a storage volume which is partitioned into data blocks having a unique block identifier (ID) and a same block size. The storage control system receives data items and assigns a respective unique data ID to each data item, which include consecutive data IDs. The data items are written to a free data block as a whole, and a record for the written data block is inserted into a node of a first tree structure. The record includes the unique block ID of the written data block, a first data ID of the data items, and a bitmap which maps the consecutive data IDs of the data items in the written data block, starting from the first data ID, to a respective bit whose value indicates whether the data item associated with the data ID is valid or invalid.
