System Architecture

			     Requirements
Partitioned and layered
 - distributed components use extensible representation/communications.
 - interchangeable storage, interaction, and presentation components.
    NOTE: identical to Cambridge Group model for DCE use.
 - (Figure 3 from architecture spec)
Incremental implementation
 - gradually integrate legacy data, systems, and desktops.
Co-opt existing systems
 - no system is forced out before its time.
 - multiple generations can coexist.
Preserve existing data
 - data (not look & feel) is the center of the Tornado.
 - legacy data lives until it can be safely replaced.

			       Features
Detail-neutral model
 - any database, any network, any desktop.
Multiple views
 - presentation according to platform capability and user needs.
 - presentation never a part of the primary data.
Data integration
 - organize data across multiple databases.
Mobile computing support
 - cache data at time of use
 - placeholders allow work to continue when data is offline

			       Benefits
Low initial capital investment
 - growth as needed to support use, not deployment.
Minimal disruption
 - existing systems remain online until integrated.
Clear future growth path
 - architectural model rather than product/vendor/standard tie-in.


Figure 3 - 

    +---------------------------------------------------------------+
    |                                                               |
    |  Machine                                                      |
    |                                                               |
    |  +---------------------------------------------------------+  |
    |  | P                                                       |  |
    |  |                   Human Interface                       |  |
    |  |                                                         |  |
    |  +---------------------------------------------------------+  |
    |                              |                                |
    |                              |                                |
    |                              |                                |
    | ...=======================================================... |
    |      |           |           |           |     R/C     |      |
    |      |           |           |           |             |      |
    |      |           |           |           |             |      |
    |   I  |        I  |        I  |        I  |          I  |      |
    |  +-------+   +-------+   +-------+   +-------+     +-------+  |
    |  |       |   |       |   |       |   |       |     |       |  |
    |  | data  |   | f (x) |   | f (x) |   | f (x) | ... | f (x) |  |
    |  |access |   |  1    |   |  2    |   |  3    |     |  n    |  |
    |  +-------+   +-------+   +-------+   +-------+     +-------+  |
    |      |           |           |           |             |      |
    |      |           |           |           |             |      |
    |      |           |           |           |             |      |
    |      |           |           |           |     R/C     |      |
    | ...=======================================================... |
    |                              |                                |
    |                              |                                |
    |                              |                                |
    |  +---------------------------------------------------------+  |
    |  | S                                                       |  |
    |  |                        Database                         |  |
    |  |                                                         |  |
    |  +---------------------------------------------------------+  |
    |                                                               |
    +---------------------------------------------------------------+