Software Engineering

17.1 
Products of software requirements definition
The following products must be generated during this stage of software development:
1. 
Operational model
. The operational model is intended to depict how the 
product will be utilized to facilitate a business or embedded system process. 
The operational model should treat the software product as a “black box” 

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17.1 
Products of software requirements definition
and should not attempt to identify any aspect of the product design or inner-
workings. The operational model should depict how the software product works 
cooperatively with operators and elements of the computing environment to 
accomplish its intended purpose. The operational model should address the 
functional sequences (including concurrent data processing transactions), the 
duration of each task, and the exchange of data (interfaces) with elements 
of the computing environment, other systems or applications, and operators. 
The resources that are necessary to conduct each function should be identified 
and whether these resources are temporarily seized, consumable, or shared. 
The operational model must address the level of data processing necessary to 
establish the test threads that will be used to determine the acceptability of the 
product.
2. 
Initial software behavioral model
. The software behavior model is intended 
to depict how the software product works cooperatively with operators, and 
the computing environment to accomplish data processing transactions. The 
behavior model represents a decomposition of the operational model with an 
emphasis on understanding how the operational functions allocated to the soft-
ware product will be performed. The software behaviors describe the functional 
flow, control flow, and data flows associated with the accomplishment of each 
transaction. The behavioral model should address each data processing transac-
tion, as necessary, to adequately specify the software behaviors at the software 
configuration item or product level. The model represents 
what
 data processing 
functions must be performed, and should not represent 
how
 it is physically or 
structurally accomplished.
3. 
Software requirements specifications (SRS)
. The functional and performance 
requirements that have been allocated to the software product must be docu-
mented in the SRS. The requirements may be allocated among multiple 
software configuration item specifications. It should capture the functional 
behaviors, data exchange requirements, and interface requirements including  
the human–machine interface requirements identified by the operational  
model. These interface requirements may be documented in separate software 
interface specifications (see item 5). The software distribution, training, and  
sustainment requirements must also be specified. These post-development 
requirements may be documented in separate post-development concept  
documents (see item 7). The software requirements specification should  
establish a matrix that identifies the software qualification method (analysis,  
demonstration, inspection, or extrapolation) that applies to determining success 
of a test.
4. 
Computing environment requirements specifications
. The operational require-
ments that have been allocated to the computing environment should be docu-
mented in the computing environment requirements specification. It should 
identify the computational processing resource requirements, including com-
munication and network bandwidth, the minimally acceptable and objective 
number of concurrent transactions to be processed, and other transaction quality 

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