9.8: Dependencies On Other Project Components

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By its nature the information management component depends on and interacts with virtually every other module of the software (and hardware) implementation to varying degrees:

Here are some concrete examples of the impact of this entwinement (of the IM component with the rest of the software) on the software development process:
The schema design must incorporate FITS keyword lists established for DEIMOS data as well as lists of keywords recognized by all machine control and monitoring processes (which in turn are constrained by actual hardware design decisions).
The observer interface must be integrated seamlessly into the general DEIMOS user interface, using identical look/feel conventions.
The information management programmer must work and closely with the data storage (FITS) designer and the user interface designer, both to comply with their requirements and to provide them with additional features and tools.

In addition, the information management system must be almost complete by the time the instrument is lab-tested, as it will be used first by the hardware and software engineers as they construct and test each component of the instrument. Their requirements will evolve as the testing process continues, so the info management software will undergo gradual continuous revision from lab test through commissioning and into first real observational use of the instrument. The information management designer must work closely with the hardware and software engineers, both to integrate software with their modules and components and to provide them with early information management services.

The information management component, in short,

Much of the schema can be prototyped well in advance of lab testing, but cannot be finalized until after commissioning. Much of the software can be prototyped in advance of lab testing, but cannot be tested until the rest of the machine control and data taking code is working. The IM designer must cooperate closely with all of the other engineers and designers, and cannot produce a working system without constant reference to their progress and requirements.

In general the IM software might best be developed as a "final layer" on top of completed control and monitoring systems. Other subsystems can be developed and tested using I/O to flat files, after which the database interface replaces the flat file I/O.

De Clarke
UCO/Lick Observatory
University of California