| 摘要 |
<p>A system for recording and retrieving data on a recording medium (10), particularly useful in write-once media such as optical disks on which data (42) pertaining to a particular subject is periodically written or changed and is interrupted by other intervening information (39A). A set of data (42) or information (39A) affecting a directory is written onto the disk in a transaction together with back-pointers to a previous transaction affecting that data or directory. The system reads transaction in reverse order until encountering a transaction affecting a desired data (42) or directory (39A), and then reads and stores a description of the data (42) or the directory information (39A) in the transaction. The back-pointer directs the system to another previous transaction affecting that data (42) or directory (39A), and so on until the system has established a complete description of a desired data or directory information by reading all necessary portions of relevant transactions. Information pertaining to particular data or directories is periodically consolidated and recorded onto the medium (10) to reduce the back-pointing process.</p> |
