Reengineering Process
An ordered set of activities designed to perform a specific task is called a process.
For ease of understanding and communication, processes are described by means of __________
For example, in the software development domain, the Waterfall process model is widely used in developing well-understood software systems.
Process models are used to comprehend, evaluate, ___________, and improve processes.
Intuitively, process models are described by means of important relationships among data objects, ________, activities, and __________.
We will discuss five process models for software reengineering.
The five approaches are different in two aspects:
(i) the extent of ________________, and
(ii) the ___ of substitution of the operational system with the new one. عارف مش عارف .
Big Bang Approach
The “Big Bang” approach replaces the whole system at once.
Once a reengineering effort is initiated, it is continued until __ the objectives of the project are achieved and the target system is constructed.
This approach is generally used if reengineering cannot be done in parts.
For example, if there is a need to move to a different system architecture, then all components affected by such a move must be changed at once.
The consequent advantage is that the system is brought into its new environment all at once.
The disadvantage of Big Bang is that the reengineering project becomes a _____ task, which may not be desirable in all situations.
In addition, the Big Bang approach consumes too much ___ at once for large systems, and takes a long stretch of ___ before the new system I visible.
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Incremental Approach
In this approach a system is reengineered _____, one step closer to the target system at a time.
For a __ system, several new interim versions are produced and released.
Successive interim versions satisfy increasingly more project goals than their preceding versions.
The advantages of this approach are as follows:
(i) locating errors becomes easier, because one can clearly identify the newly added components, and
(ii) It becomes easy for the customer to notice ___, because interim versions are released.
The disadvantages of the incremental approach are as follows:
(i) with multiple interim versions and their careful version controls, the incremental approach takes much longer to complete, and
(ii) even if there is a need, the entire architecture of the system cannot be ____. عارف مش عارف .
Partial Approach
In this approach, only a part of the system is reengineered and then it is integrated with the non-engineered portion of the system.
One must decide whether to use a ______ approach or an ______ approach for the portion to be reengineered.
The following three steps are followed in the partial approach:
• In the first step, the existing system is _____ into two parts: one part is identified to be reengineered and the remaining part to be not reengineered.
• In the second step, reengineering work is performed using either the “Big Bang” or the “Incremental” approach.
• In the third step, the two parts, namely, the not-to-be-reengineered part and the reengineered part of the system, are ______ to make up the new system.
The partial approach has the advantage of reducing the scope of reengineering that is less time and costs less.
A disadvantage of the partial approach is that modifications are not performed to the _______ between the portion modified and the portion not modified. عارف مش عارف .
Iterative Approach
The reengineering process is applied on the source code of a ___ procedures at a time, with each reengineering operation lasting for a ___ time.
This process is repeatedly executed on different components in different stages.
During the execution of the process, ensure that the ___ types of components can coexist:
old components not reengineered,
components currently being reengineered,
components already reengineered, and
new components added to the system.
There are two advantages of the iterative reengineering process:
(i) it guarantees the ____ operation of the system during the execution of the reengineering process, and (ii) the maintainers’ and the users’ familiarities with the system are preserved.
The disadvantage of this approach is the need to ___ ____ of the four types of components during the reengineering process.
In addition, both the old and the newly reengineered components need to be maintained.
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Evolutionary Approach
In the ”Evolutionary” approach components of the original system are substituted with ___________.
In this approach, the existing components are grouped by _______ and reengineered into new components.
Software engineers focus their reengineering efforts on __________ irrespective of the locations of those components within the current system.
As a result, the new system is built with functionally ____ components as needed.
There are two advantages of the “Evolutionary” approach:
(i) the resulting design is more cohesive, and
(ii) the scope of ______ components is reduced.
A major disadvantage:
(i) all the functions with much similarities must be _______ throughout the operational system.
(ii) next, those functions are refined as ______ in the new system.
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• The SCORE/RM model was proposed by Colbrook, Smythe and Darlison.
• The framework consists of four kinds of elements:
– function,
– documentation,
– repository database, and
– metrication.
• The function element is divided into eight layers, namely:
– encapsulation, transformation,
– normalization, interpretation,
– abstraction, causation,
– regeneration, and certification.
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• The eight layers provide a detailed approach to:
(i) rationalizing the system to be reengineered by removing _______ data and _____ the control flow,
(ii) _________ the software’s requirements, and
(iii) reconstructing the software according to established practices.
• The first six of the eight layers together constitute a process for _____ engineering, and the final three a process for _____ engineering.
• Improvements in the software as a result of reengineering is quantified by means of the ___ element.
• The metrication element is described in terms of the relevant software metrics before ______ and after executing the ______
.
• _________ is the information store for the entire reengineering process, containing the following kinds of information:
– metrication,
– documentation, and
– both the old and the new source code.
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