Softstar Systems

COCOMO and COSYSMO Estimation Tools

Advanced Topics


SystemStar Guided Tour

SystemStar Features

SystemStar Facts

Download Demo

Price List


COCOMO Overview

COCOMO History

COCOMO Cost Drivers

COCOMO II Features

Function Points

Incremental COCOMO


COSYSMO Overview

COSYSMO Features



What's New

Contact Us

Incremental COCOMO

Incremental Development COCOMO was defined at the same time as Ada COCOMO. Incremental COCOMO is a modern alternative to the traditional Waterfall model of the software development process.

Incremental Development COCOMO lets you model a variety of development processes. Instead of modeling your software development as if it were a single effort devoted to inventing a single product, Incremental Development COCOMO lets you model development as a series of concurrent software projects, each yielding an intermediate product.

This strategy reduces your risk, and permits you to deliver an initial product to your customer earlier.

We've extended and generalized the definition so that SystemStar performs the calculations for increments with multiple components.

You can use SystemStar's worksheets to define which development phases are included in each increment, and how each increment is synchronized with the other increments. You can add delays between phases or between increments to match your schedule.

You can assign any component to any increment.

Incremental Development can be used with any COCOMO model.

Function Points

The Function Point methodology was developed by Allan Albrecht at IBM.

The Function Point methodology is based on the premise that the size of a software project can be estimated early, during the requirements analysis, based upon the inputs and outputs of the system. Five classes of items are counted:

  1. External Inputs
  2. External Outputs
  3. Logical Internal Files
  4. External Interface Files
  5. External Inquiries

Based upon counts for each of these items, and the weighting factors and adjustment factors that Albrecht proposes, you can calculate a Total Function Point count.

SystemStar converts the Function Point count into an equivalent number of SLOC, and uses that in the COCOMO equations to make its estimates.

Using SystemStar

Most of your interactions with SystemStar will involve creating and modifying components. You'll define subcomponents, assign cost driver values, estimate the size of each component, etc.

One component is always distinguished as "the current component". The name of the current component, the cost drivers you've assigned to it, and other data describing the current component are shown in the main SystemStar window.

A given component may be made up of any number of subcomponents. When you create a new subcomponent, it becomes a subcomponent of the current component. It inherits values for each of its attributes from its parent component. The following attributes are inherited:

SystemStar makes it easy to perform "what-if" analyses, and to compare different project plans. You may develop a new estimate based upon an older one, and then use SystemStar to compare the two.

A SystemStar estimate consists of:

One estimate is always distinguished as "the current estimate". All of the SystemStar commands operate on the current estimate.

When there is only a single component in an estimate, the SLOC value for the component is identical to the total SLOC value for the estimate. But when a component has subcomponents, the SLOC value is derived from the SLOC values of its subcomponents.

SystemStar lets you specify SLOC values in three different ways:

  1. You can explicitly enter a SLOC value such as 3,000.
  2. You can use the Reuse Tab to calculate the SLOC.
  3. You can use the Function Point Tab to calculate the SLOC.