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Chronicle: Application-Specific Versions

A problem with traditional file systems is that the unit of naming, storage, and versioning is a physical unit supported by the system rather than a logical unit specific to an application. Chronicle [], addresses this issue within the context of a spreadsheet. It has been developed as an extension to Lotus 1-2-3, and allows users to collaborate on spreadsheets. It supports multiple versions of the spreadsheet state, and allows users to share spreadsheet information.

Chronicle supports the abstraction of a named range, which is a named rectangular block of cells in a spreadsheet, and allows a user to ask for the values in the range to be stored as a new version. A version is associated with the range values, the range name, a user-defined annotation, a user id, date, and time stamp.

Users can include different named versions in a spreadsheet and perform computations on them. This feature can be used in at least two different but related ways: (1) Users can include data composed by different users such as ``Sally's expense data'' and ``Joe's sales data'' into a single spreadsheet and (2) they can try different versions of a named range such as ``Sally's expense forecast'' and ``Joe's expense forecast'' to try different alternatives. Note that the second benefit is useful also in the single-user can who can create different versions for ``my best case sales forecast'' and ``my worst case sales forecast''. It is often the case that features added to an application for supporting collaboration are also useful in the single-user case. A spreadsheet that includes named ranges is called a scenario.

Chronicle allows versions and scenarios to be stored in databases shared among distributed users and also allows them to be mailed to each other explicitly. It also allows users to browse through the various versions of a named range stored in a shared database and indexes them by range name, user name, and scenario. It also allows users to simultaneously access a spreadsheet but not a version. Simultaneous changes to the same part of a spreadsheet create different versions of it that can later be used as alternatives.



next up previous
Next: Session- and Message- Up: Artifact-based Collaboration (File++) Previous: CLARE: Structured Discussion



Prasun Dewan
Tue Jan 28 17:46:09 EST 1997