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Related work

Old typed file systems are obviously ancestors of the box abstraction. However, neither type converters nor a share operation were present on them. Converters are also missing on those systems mentioned below.

Some modern typed file systems, like the one used by Nemesis [3], allow applications to install new file types, tailoring the implementation of the file system to exploit semantic information. Boxes are of a higher level of abstraction, and are not related to the implementation of disk related policies.

Boxes (and specially their share operation) are also strongly influenced by distributed-shared-objects (DSO) [4]. However, DSO do not have converters, and can present much more complex interfaces. In fact, interfaces for different DSO can be entirely different. Some OO file systems (e.g. Frigate [5]) support different file types (with different interfaces), while maintaining the traditional, simple, file interface.

Work on distributed systems supporting mobile computing such as Odyssey [6] can also be applied for implementing boxes (specially, the share operation), including support for disconnected operation [10]. Odyssey includes wardens, to include support for specific shared object data types. Boxes follow that model so that application semantics can be incorporated (and applied) in a natural way (by defining new box types for application data).

The Khazana [2] system supports a distributed persistent shared state abstraction, representing application data which can be shared. Boxes are more generic in spirit. A box can be created on volatile memory, be destroyed later, and never persist. Only some boxes will persist. Nevertheless, results from research on Khazana can be applied for implementing boxes.

Finally, the diversity of interfaces in object and DSO based environments makes it harder to apply a single utility program (e.g. ``grep'') to different types of data. Moreover, it is not yet clear if system users and applications would feel comfortable with interfaces changing on a per-object basis.


next up previous
Next: Status and future work Up: The Box: A Replacement Previous: Devices and special boxes

1999-02-26