Software Cost Estimation and Boehm's COCOMO Model

1. Software cost estimation

Software cost estimation is the process of predicting the effort, development time and cost required to develop and maintain a software system.

It is usually based on factors such as:

• Size of the software, often measured in KLOC (thousand lines of code).
• Required reliability and complexity.
• Team capability and experience.
• Tools and technology.
• Schedule and development environment.

2. Basic COCOMO

Boehm's COCOMO (Constructive Cost Model) estimates development effort and schedule from software size.

For the basic model:

Effort (person-months) = a × (KLOC)^b

Development Time (months) = c × (Effort)^d

The coefficients depend on the project mode.

Mode	Effort equation	Time equation
Organic	2.4 × KLOC^1.05	2.5 × Effort^0.38
Semi-detached	3.0 × KLOC^1.12	2.5 × Effort^0.35
Embedded	3.6 × KLOC^1.20	2.5 × Effort^0.32

3. Given problem

Embedded project = 50 KLOC

For an embedded project:

Effort = 3.6 × (50)^1.20

Effort ≈ 393.61 person-months

Now calculate development time:

Tdev = 2.5 × (393.61)^0.32

Tdev ≈ 16.92 months

Final result

• Estimated effort ≈ 393.6 person-months
• Estimated development time ≈ 16.9 months (about 17 months)

Exam note: This calculation uses the Basic COCOMO coefficients for the Embedded mode, which is the standard interpretation of the question.