which is passed to users / actors / other software components outside the system
boundary.
There determination of the system boundary can be quite subjective, but nevertheless
really important, since Function Points are allocated to the application / software
component being estimated based on this determination. Function Point Analysis is not
difficult, in many senses, but can be vexing when there is little or no documentation.
The system within the system boundary can be decomposed into sub-systems, and each
subsystem can be further decomposed into atomic transactions. An atomic transaction is
the lowest level logical transaction, which, when completed, results in either a successful
completion of a business operation, or a graceful exit because of an error condition. For
example, updating a customer record successfully is an atomic transaction. Trying to add
a customer record to a database where one already exists results in an error condition
which requires a graceful error message, and this too, is an atomic transaction.
Next, for each atomic transaction, the FP analyst needs to figure out the number of
unique input data fields. For example, for a unique customer record, the primary key
might compose of the Customer Last Name, Customer First Name, and Customer
Number. Next, the FP analyst needs to identify the output data fields upon the successful
completion of a customer record. These might be the Customer Name, Customer
Number, Customer Address, Customer Zip Code, Customer State, Customer Country,
Customer Work Phone Number, Customer Mobile Phone Number, Customer Web Site,
and Customer Email address. To create this customer record in the Customer Table, other
tables / records may need to be accessed, such as a list of cities/states/zip codes/
countries. Each of these is a separate entity, like the customer record is a separate entity.
The FP analyst needs to make a note of that.
4.2 COSMIC - Common Software Measurement International
Consortium
COSMIC is an evolution over FPA. Whereas FPA emerged because of a crying need to
size business software / business applications, COSMIC helps in estimating both
application as well as system software such as computer / router operating systems,
clustering / storage / database software, middleware / SOA (service oriented architecture)
/ application server software, user interface / browser software, etc. For more details on
COSMIC, please visit
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