Software Life-cycle Model (SLIM)


Putman’s software lifecycle management refers to one of the early algorithmic cost models which provides aa sequence of activities or rather procedures for system developers and designers to follow while developing software. The model is based on Norden/Rayleigh function commonly known as macro estimation model.  The paper will give a report on the Putnam’s software life-cycle model (SLIM). The report will also include the strengths and the weaknesses of the model.

Several phases need to be complied to for the evaluation of the software; the first phase is understanding the problem which is achieved through requirements gathering. The second phase is deciding a plan for a solution which involves designing, and the third stage is coding the expected solution. The fourth phase is giving a test to the actual program, and the last phase is product development and maintenance.

Putnam’s software lifecycle management (SLIM) enables a software cost estimator to undertake functions such as building a software’s information model collecting personal attributes, computer attribute and software characteristics. The other function is software sizing, software lifecycle management (SLIM) makes the use of automated version of lines of code (LOC) cost technique. The other function is calibration which involves tuning the model for representing local software development environment by the historical interpretation of past project’s database.

The algorithm used in Putnam’s software lifecycle management (SLIM) is as follows.

K=(LOC/(C*t4/3)) *3

From the equation the variable K refers to the total life cycle effort in working years, t refers to the development and the last variable C represents the technology constantly. The equation then utilizes the aspect of using tools, methodology, languages and quality assurance in a broader perspective. From the equation, we also find that the technology constant varies from 610 to 557314.

The use of Putnam’s software life cycle management we encounter or rather realize strengths and weaknesses of the model. From the use of SLIM, we find that there is the use of linear programming in considering development constraints on both effort and cost. The other advantage or rather strength is that software lifecycle management (SLIM) has fewer parameters that are required for the generation of an estimate over constructive cost model (COCOMO’II) and COCOMO’81.

The constructive cost model 81 was derived from 63 software projects back in the year 1981 which led to its name of COCOMO’81. The model is a single valued static model computing software development cost and effort estimated in lines of code (LOC). On the other hand, we find COCOMO’II which started in the late 90s to replace COCOMO’81 is insufficient to apply in new practices of software development. As compared to COCOMO’ 81 we find that COCOMO’11 is designed to have three models such as application composition model, the early design model and lastly the post- architecture model.

On the other hand, we also experience the weaknesses of its applications such as estimates are more sensitive to the technology factor making it a weakness for its implementation. The other drawback is that it is not suitable for smaller projects.



From the Putnam’s software life cycle management, we get to understand its functions in the development of software through the models. The application of SLIM in most cases accrues to advantages such as the use of linear programming in development constraints on cost and efforts. Similarly, the use of SLIM model has some noted weaknesses such as the use in smaller projects.















Work Cited

Basili, V. R., & Musa, J. D. (1991). Future engineering of software: A management perspective. Computer, (9), 90-96.

Boehm, B., Abts, C., & Chulani, S. (2000). Software development cost estimation approaches—A survey. Annals of software engineering, 10(1-4), 177-205.

Putnam, L. “Software Life Cycle Model (SLIM).” (2001).


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