Software Engineering

194
CHAPTER 11 
Functional Analysis and Allocation Practice
straightforward action that can be satisfactorily designed, implemented, and tested 
by a competent software professional.
11.2.6 
Identify resource prerequisites
The resources that are necessary for each function to execute must be identified. 
A resource represents an item that enables a function to be performed properly. 
When a resource is unavailable, the data processing transactions may be suspended, 
delayed until the resource is made available, or performed inefficiently. Resources 
can be thought of as the computing resources or intermediary data items that need 
to be present for the function to fulfill its purpose.
There are two types of resources that must be addressed to support behavio-
ral analysis. The first type of resource is one that is consumable. A resource that 
is consumed represents an inventory stock that may be incrementally utilized until 
the inventory is empty or of insufficient quantity to support further data processing 
actions. A function that requires a consumable resource must wait until the inventory 
stock has been replenished before it can be executed. An example of a consumable 
resource is a printer with its paper supply. As long as there is paper available within 
the tray, the printing function can be performed. However, when the paper supply is 
empty, the printing function is suspended until the paper supply is restocked.
The second type of resource represents a reusable item, such as memory. Each 
function is loaded into memory for execution, and unloaded from memory when 
the function is no longer necessary to be resident in memory. The amount of mem-
ory is fixed and is temporarily decremented by the amount consumed by resident 
functions. When a function is removed from memory it frees up space for other 
functions that may require the memory for execution purposes. Understanding the 
amount of available memory at any point in time is crucial to software performance 
and is dictated by the computer’s memory management scheme.
Resource utilization is a critical aspect of overall software performance. 
The time associated with resource management and delays imposed by limited 
resources may adversely affect processing time. Therefore, resource allocation and 
management contribute directly to the establishment of a functional architecture 
that satisfies stringent performance requirements. Therefore, task 11.3.2, allocate 
resource budgets, involves an assessment of the functional resource availability and 
utilization and management scheme, and establishes the approach to software per-
formance requirements allocation among elements of the functional architecture.