Software cost evaluation: basic knowledge interpretation of cosmoc method

COSMIC Method defines Measure the standard function size of a software Principles 、 Rules and processes .“ Function size ” It is a measure of the amount of functionality expressed in terms that users can understand . Function size is usually determined by requirements , But it can also be from other software products （ For example, design 、 Installed system, etc ） Reverse estimation in .

COSMIC Basic knowledge of methods

 Every data movement  = 1 COSMIC  The function point  (CFP)

• Get into ： The data movement of the mobile data group comes from the function user to cross the border and enter the required function process .
• sign out ： Move the data group from the data moved across the boundary of the function process to the function user .
• Read ： Data movement that moves a data group from the repository to the functional process that needs it .
• write in ： Move the data of the data group from within the functional process to the repository .

COSMIC Applicability of the method

COSMIC Method can be used to determine the size of any software , For example, business applications 、 Real time software 、 Infrastructure software ; For example, operating system ; And the mixture , In short , All software .

• Applicable to any level of decomposition , for example “ Whole ” Software or any of its components 、 Sub components, etc ;
  • Applicable to any layer of multi tier architecture ;
  • Applicable at any time in the software life cycle ;

Measuring software COSMIC The principle of function size

This method uses a software model , be called “COSMIC Common software model ”, It is based on basic software engineering principles , namely ：

• The functional user requirements of a software can be analyzed as a unique functional process , These processes consist of sub processes . Subprocesses can be data movement or data manipulation ;
• Each function flow is controlled by the function user “ Input ” Data movement trigger , The mobile notification function process function user has identified the events that the software must respond by sending event related data ;
• Data movement movement describes a single “ Objects of interest ” Single attribute data set of , The latter is of interest to function users “ thing ”;

Approximate values for measurement purposes , The data operation sub process is not measured separately . then , The size of the software is defined as the data movement during all functions of the software （ Get into 、 sign out 、 Read and write ） Total of . Each data movement counts as a “COSMIC The function point ”(CFP). The minimum size of the functional flow is 2 CFP. There is no upper limit on the size of functional processes .

Measurement software COSMIC The process of function size

COSMIC The measurement process is divided into three stages , As shown in the figure below ：