What are different compatibility and intersystem defects?

WHAT IS MEANT BY SOFTWARE COMPATIBILITY?

- Software compatibility is usually described as the compatibility of a software system or application to run without any problems on any major platform.
- It means that the software system or application is compatible with the major platforms and CPU architectures such as Intel or mercury etc.
- It also refers to the compatibility of a software system with different operating systems.
- It is very difficult to develop software that is compatible with many CPU architectures since during the compilation of such a system it shows different errors for the different CPU architectures.
- But such compatible application software do exist.
- The applications are developed and compiled for the various CPU architectures and these are then made compatible to with the various different CPU architectures via the operating systems.

WHAT IS INTERPRETED SOFTWARE?
- In contrast to the compiled software, the interpreted software does not show the above drawback.
- They are very well capable of running on multiple CPU architectures.
- But here one condition has to be fulfilled i.e., the interpreter should be available for that particular type of the CPU architecture.

Software incompatibility is more frequent among the newer software versions developed for the new versions of the operating system which is found to be incompatible with the older version of that software system or application version due to a lack of some features and functionalities.

The newer versions of a software system or application that are able to work with the older versions of the operating systems are said to possess the capability of the backward compatibility.

Compatibility testing is usually carried out to test the operational environment of a software application or program. The software system or application is checked for its suitability i.e., whether or not the application will be able to perform in that environment or not.

DIFFERENT COMPATIBILITY & INTER-SYSTEM DEFECTS
Defects affecting the compatibility of a software system or application are commonly called as compatibility and inter-system defects. These are:

DEFECT #1:
After completing the installation of the application software, the user executes that application and observes that he/she is not able to access some features and functionalities and also not able to view any pictures images, icons or data.

DEFECT #2:
Some browsers may show java script errors with applications developed in java language.

DEFECT #3:
Inconsistency is observed in some elements of a web application or a web site when viewed through different browsers.

DEFECT #4:
The software program is observed to behave differently on different browsers.

DEFECT #5:
Inter-system defects like corruption of data in an NFS mounted file. Usually data is not corrupted in an NFS system.

DEFECT #6:
- In some cases, an unauthorized user is very well able to access the control to a system which uses the LDAP methodology for the authentication purpose.
- This inter-system defect is common in ensemble, UNIX clients and VMS employing LDAP authentication system, windows clients and cache file versions.

DEFECT #7:
- Encryption of data base in VMS clusters.
- In such a defect the system usually becomes inactive and does not respond.
- Like the above mentioned defect, this defect also exists in ensemble versions. - This defect usually occurs when the data base is forced to shut down without the cache being closed.

DEFECT #8:
Failure of cluster mounted data bases.

DEFECT #9:
- Defect making the application server unresponsive.
- This defect is usually encountered when there is too much ECP traffic on the application or web site.
- This defect can affect all platforms.

DEFECT #10:
- Memory defects like core dumps which are generated during the start up of the cache.
- Because of this defect in some cases the start up can fail completely.

DEFECT #11:
Speed reduction in cache making it unresponsive. This defect occurs mainly when the amount of shared memory exceeds a specified limit.

What are different user interface design principles and guidelines in software engineering ?

A good web application interface is understandable and forgiving, providing the user with a sense of control. The inner workings of the system are not for concern for the users. Effective applications perform a maximum of work, while requiring a minimum of information from users.

USER INTERFACE DESIGN PRINCIPLES AND GUIDELINES

- Consistency of actions should be required in similar situations. The use of navigation controls, menus, icons should be consistent throughout the web application.
- Anticipation Web application should be designed in such a way that it should interpret the user's next move.
- Communication Whatever activity that is been initiated by the user, it should be communicated by the interface. Communication can be obvious or subtle. User status and location should also be communicated by the interface.
- Efficiency Users work efficiency should be optimized by the design of the web application and its interface and not the efficiency of the web engineer who designs and builds it.
- Flexibility Flexibility of the user interface should enable some users to get the tasks done directly and some other users to explore the web application in random fashion.
- Controlled Autonomy User movement should be facilitated by the interface in such a manner that enforces navigation conventions that are established for application.
- Focus The interface of the web application should be focussed on user tasks at hand.
- Human Interface Objects Use reusable human interface objects. An interface object that is seen, heard, touched by the end user can be get from the object libraries.
- Learn ability Learning time should be reduced by a well designed web application interface.
- Latency Reduction The web application should use multitasking so that the user can proceed with his work and do not wait for some internal operation to get completed.
- Metaphors A metaphor should call images and concepts from user's experience, but it does not need to be an exact reproduction of real world experience. The web application interface that uses an interaction metaphor is easier to learn and use.
- Maintain work product integrity A work product must be automatically saved so that there is no loss of information if an error occurs.
- Readability Every person should be able to read the information in the user interface.
- Track State The state of the user interaction should be saved and stored so that the user can return to the same point even if he or she logs off.
- Visible navigation A well designed web application interface provides the illusion that users are in the same place, with the work brought to them.

What is a defect and what is defect management ?

Defects determine the effectiveness of the testing what we do. If there are no defects, it directly implies that we do not have our job. There are two points worth considering here, either the developer is so strong that there are no defects arising out, or the test engineer is weak. In many situations, the second is proving correct. This implies that we lack the knack.

For a test engineer, a defect is:
- any deviation from specification.
- anything that causes user dissatisfaction.
- incorrect output.
- software does not do what it intended to do.

Software is said to have bug if it features deviates from specifications.
Software is said to have defect if it has unwanted side effects.
Software is said to have error if it gives incorrect output.

Categories of Defects
All software defects can be broadly categorized into the below mentioned types:
- errors of commission : something wrong is done.
- errors of omission : something left out by accident.
- errors of clarity and ambiguity : different interpretations.
- errors of speed and capacity.

Types of defects that can be identified in different software applications are conceptual bugs, coding bugs, integration bugs, user interface bugs, functionality, communication, command structure, missing commands, performance, output, error handling errors, boundary-related errors, calculation errors, initial and later states, control flow errors, errors in handling data, race condition errors, load conditions errors, hardware errors, source and version control errors, documentation errors and testing errors.