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Quite often the Functional User Requirements (FUR) is not available, incomplete or has insufficient detail. In these cases the FP Analyst must rely on the information contained in the physical artefacts, and the knowledge of the Subject Matter Expert (SME)
Because it is less rigourless and quicker to do, It may be tempting to use the Physical artefacts directly (e.g. GUI screens and Menus) and produce the measure of the size.
A more rigorous approach is to first construct the missing FUR, again using the knowledge of the SME. Once the FUR have been agreed by all parties, the size of the FUR is measured. The advantages of this approach are:
1. There can be no challenge to the validity of the measure being a true measure of the functionality.
2. You have captured once and for all the knowledge of the SME in a form that can be understood by anyone.
3. You have effectively reverse engineered the software by generating the underlying FUR
All the major Functional Size Measurement Methods (FSMMs) comply with IS0 14143-1. The main requirement of that standard is that they shall measure functional size as expressed in the software Function User Requirements.
If the same FUR is measured using 2 FSMMs, the sizes will invariably be different as they employ different measurement models (e.g. metric vs. imperial). However because they are measuring the same functionality there must be a relationship between the 2 size measures (e.g. as there is between Metric and Imperial).
We will call this relationship the Method Size Conversion Ratio (MSCR). If you are considering converting from one method to another, unless you are prepared to re-measure the entire portfolio using the new method you will need to know the MSCR.
Pentad-SE firmly believes in the COSMIC FSMM; it is the newest FSMM, it is more relevant to modern development practices; it can be used to measure software from a variety of domains, and it can accommodate modern Architecture Design practice where software functionality is allocated to multiple, collaborating components.
Pentad-SE has therefore developed a product it calls convert2COSMIC. It comprises a service and a software application.
The objective of the service, given a sample set of your portfolio, is to provide you with a fully documented functional size measurement report of the size of the sample using the COSMIC FSMM. The report contains the MSCR. If requested we apply the MSCR to the rest of your portfolio and provide you with a report of the total size.
These are the steps involved (with variations). Please note: it may be necessary for you to have more than one sample set if the portfolio contain software from different domains.
1. You select a sample set of FUR from your portfolio. The sample must be representative of the software you intend to measure using COSMIC.
a. If the FURs are not available we will do the front-end reverse engineering activity to generate them.
b. Otherwise you give us access to the FUR
2. You provide us with the measured size of the samples provided, together with any local counting practices and we will measure the size in your current FSMM.. If you do not have a measurement of size, we will do it, and it will be documented in the final report
3. We will measure the size of the sample using the COSMIC FSMM
4. We will deliver a comprehensive report containing a fully documented record of the measurement exercise, and the MSCR for the sample.If you provide us with the measured sizes of the remaining functions in your portfolio we will apply the MSCR and provide you with a detailed size report
To support the service Pentad-SE has developed a suite of software module under the application name fsmIT. Details of the various modules can be found on the website at http://www.pentad-se.com. To support the convert2cosmic service Pentad-Se utilises:
1. fsmit-COSMIC. To reverse engineer the FUR if necessary, to build the common function model, and to measure its size in COSMIC Function Points, and depending on the FSMM to be converted from
2. fsmIT-IFPUG. To measure the common function model in IFPG Function Points
3. fsmIT-MkII. To measure the size of the common function model in FPA MkII Function Points
The software is available for purchase should you wish to do this yourself.
| Copyright (c) 2009 Pentad-SE Ltd. All rights reserved | Traduction par Nathalie Amalric |