The existing system grew to be what it is in large part because of the environment in which it exists. Studying the system can give clues as to what the environment is that the new system must deal with. Quite often, it is much more "interesting" than the system specification would lead you to believe. "Environment" here can mean the funding situation, the political situation, the underlying hardware and/or software, the business rules, interface reliability, data integrity, and more.
Quite often, the existence (or lack) of certain capabilities within the system changes the way people interact with it and with each other. Also, those capabilities can give clues as to features that may be missing from or improperly specified in the system specification. You may find that people depend on certain defaults that are not covered in the specification.
When it comes to system analysis, things are hardly ever what they seem to be.
Quite often, the existence (or lack) of certain capabilities within the system changes the way people interact with it and with each other. Also, those capabilities can give clues as to features that may be missing from or improperly specified in the system specification. You may find that people depend on certain defaults that are not covered in the specification.
When it comes to system analysis, things are hardly ever what they seem to be.