KC - 10.1 - Purchased (COTS) Software

Commercial off-the-shelf (COTS) is a term for software or hardware products that are ready-made and available for sale to the general public. They are often used as alternatives to in-house developments or one-off government-funded developments (GOTS). The use of COTS is being mandated across many government and business programs, as they may offer significant savings in procurement and maintenance.

Because a COTS product is adapted for a specific purpose, it can be purchased and used immediately. However, since COTS software specifications are written by external sources, organizations are sometimes leery of these products, because they fear that future changes to the product will not be in their control.

Several groups have been formed to encourage the development of COTS systems and promote their adoption. You can view SEI’s say on COTS @ http://www.sei.cmu.edu/cbs/

In simple terms - COTS software

• Commercial Off-The-Shelf software package
• is commercially available
• is defined by market need
• has significant functionality and complexity
• is self-contained

COTS software component selection

COTS software component selection is a process of determining "fitness for use" of previously-developed components that are being applied in a new system context Haines, 1997). Component selection is also a process for selecting components when a marketplace of competing products exists. Selection of a component can also extend to include qualification of the development process used to create and maintain it (for example, ensure that algorithms have been validated, and that rigorous code inspection has taken place).

There are three phases of COTS software selection:

1. criteria definition,
2. identification of candidate components and
3. evaluation.

The criteria definition process essentially decomposes the requirements for the COTS software into a hierarchical criteria set and each branch in this hierarchy ends in an evaluation attribute (Kontio, 1996). The criteria include component functionality (what services are provided), other aspects of a component’s interface (such as the use of standards) and quality aspects that are more difficult to isolate, such as component reliability, predictability, and usability. The identification of candidate components also known as alternative identification involves the search and screening for COTS candidate components that should be included for assessment in the evaluation phase. In the evaluation phase the properties of the candidate components are identified and assessed according to the evaluation criteria.

PROBLEMS OF COTS EVALUATION AND SELECTION
Successful selection of COTS software to fit requirements is problematic because:

Lack of well defined process - Most organisations are under pressure to perform and therefore do not use a well-defined repeatable process (Kontio, 1996). The COTS selection process is implemented in an ‘ad hoc’ manner. This makes planning difficult, appropriate evaluation methods and tools are not used, lessons from previous cases are not learnt and the evaluation process efficiency reduced.

Evaluation criteria - There are problems associated with the definition of the
evaluation criteria. Sometimes evaluators include immaterial and inappropriate attributes in the criteria, leading to incompatibilities (for example, confusing technology with product attributes). However, the more considerable problem is that evaluators tend to focus on technical capabilities at the expense of the non-technical or "soft" factors such as the human and business issues (Powell, 1997).

"Black box" nature of COTS components - Lack of access to the COTS internals
makes it difficult to understand COTS components and therefore makes evaluation hard. At times even the supporting documentation for these components is incomplete or wrong.
Rapid changes in market place - COTS evaluation is difficult because of rapid
changes in COTS components in the market place. For example, a new release of the
COTS component may have a feature that is not available in the component that is
currently being evaluated.