Why is the structure of directory systems and naming spaces often hierarchic? What is the advantages and disadvantages with this?


Advantages: The main reason for this is that it allows decentralization of the assignment of new names, while still ensuring that all names are globally unique. For every level in the name hierarchy, a different organization can assign new subnames. For example, The "se" domain assigns names like "su.se" and the "su.se" domain assigns names like "dsv.su.se".
    The hierarchical structure can also be used for decentralized storage of the directory, with different servers responsible for different positions in the tree structure.
    It is also human-friendly, people find hierarchical names easy to understand, and are accustomed to the same principle from postal addresses and phone numbers.
    Finally, a hierarchical structure can also be used to regulate access rights.

Disadvantages: A disadvantage is that every object does not have a natural place in a hierarchical structure, and that the quality of maintenance will differ for different branches of the tree.

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