Appendix C - Software Estimation 6 COCOMO comes in three levels (basic, intermediate, and detailed) with each providing progressively more accurate estimates. This section gives a brief overview of basic COCOMO. Basic COCOMO is provided for three operational modes: organic, semi-detached, and embedded. Intermediate Model: The basic Cocomo model considers that the effort is only a function of the number of lines of code and some constants calculated according to the various software systems. The intermediate COCOMO model recognizes these facts and refines the initial estimates obtained through the basic COCOMO model by using a set of 15 cost drivers based on various attributes of software.
COCOMO-II is the revised version of the and is developed at University of Southern California. It is the model that allows one to estimate the cost, effort and schedule when planning a new software development activity.It consists of three sub-models:1. End User Programming:Application generators are used in this sub-model. End user write the code by using these application generators.Example – Spreadsheets, report generator, etc.2. Intermediate Sector:.
(a). Application Generators and Composition Aids –This category will create largely prepackaged capabilities for user programming. Their product will have many reusable components. Typical firms operating in this sector are Microsoft, Lotus,Oracle, IBM, Borland, Novell. (b). Application Composition Sector –This category is too diversified and to be handled by prepackaged solutions. It includes GUI, Databases, domain specific components such as financial, medical or industrial process control packages.
(c). System Integration –This category deals with large scale and highly embedded systems.3. Infrastructure Sector:This category provides infrastructure for the software development like Operating System, Database Management System, User Interface Management System, Networking System, etc.Stages of COCOMO II:.
Stage-I:It supports estimation of prototyping. For this it uses Application Composition Estimation Model. This model is used for the prototyping stage of application generator and system integration. Stage-II:It supports estimation in the early design stage of the project, when we less know about it. For this it uses Early Design Estimation Model. This model is used in early design stage of application generators, infrastructure, system integration. Stage-III:It supports estimation in the post architecture stage of a project.
For this it uses Post Architecture Estimation Model. This model is used after the completion of the detailed architecture of application generator, infrastructure, system integration.