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MIND
OLE Structured Storage

S

toring multiple kinds of objects in one document is no easy task in a traditional file system. OLE provides a solution: a file system within a file. OLE Structured Storage defines a way to treat a single file entity as a structured collection of two object types: properties and values. This scheme is called structured storage. The purpose of structured storage is to reduce the performance penalties and overhead associated with storing separate objects in a flat file.
      Through the use of APIs or the DSOFile.dll module, OLE Structured Storage provides an easy-to-use interface for reading or writing properties such as title, author, and file comments. With Windows 95 and higher, you can read these values when you right-click on a file that was saved with OLE Structured Storage.
      Structured storage doesn't define what the properties and values must be, only how to store them. This means that structured storage properties can be used for any ancillary information that needs to be saved with a file. You could store version information for a text file, record counts on a custom database, or any other data you need.

From the March 2000 issue of MSDN Magazine.