Monday, April 21, 2003		ITerminology

COCOMO: Short for Constructive Cost Model, a method for evaluating and/or estimating the cost of software development. There are three levels in the COCOMO hierarchy:

1) Basic COCOMO: computes software development effort and cost as a function of program size expressed in estimated DSIs. Basic COCOMO is further sub-divided into Organic mode, Semidetached mode and Embedded mode.

2) Intermediate COCOMO: an extension of the Basic model that computes software development effort by adding a set of "cost drivers," that will determine the effort and duration of the project, such as assessments of personnel and hardware.

3) Detailed COCOMO: an extension of the Intermediate model that adds effort multipliers for each phase of the project to determine the cost driver’s impact on each step.

COCOMO was developed by Barry Boehm in his 1981 book, Software Engineering Economics.

DSI: Short for delivered source instruction, one line of new source code developed for software. DSI is used to estimate software cost (see COCOMO). Typically expressed in thousands of lines of code (e.g., 2,000 DSI or 2KDSI).

Companding: Formed from the words compressing and expanding. A PCM compression technique where analog signal values are rounded on a non-linear scale. The data is compressed before sent and then expanded at the receiving end using the same non-linear scale. Companding reduces the noise and crosstalk levels at the receiver.