2.6.2 Root Directory Entry
The first entry in the first sector of the directory chain (also referred to as the first element of the directory array, or stream ID #0) is known as the root directory entry, and it is reserved for two purposes. First, it provides a root parent for all objects that are stationed at the root of the compound file. Second, its function is overloaded to store the size and starting sector for the mini stream.
The root directory entry behaves as both a stream and a storage object. The root directory entry's Name field MUST contain the null-terminated string "Root Entry" in Unicode UTF-16.
The object class GUID (CLSID) that is stored in the root directory entry can be used for COM activation of the document's application.
The time stamps for the root storage are not maintained in the root directory entry. Rather, the root storage's creation and modification time stamps are normally stored on the file itself in the file system.
The Creation Time field in the root storage directory entry MUST be all zeroes. The Modified Time field in the root storage directory entry MAY be all zeroes.