What is STLC ?

Software testing life cycle

software testing life cycle identifies what test activites are to be carried out and when to. Even though testing may differ between organizations, there is a generic testing life cycle that can be applied to across all organization.
Software Testing Life Cycle mainly consists of six (generic) phases. There are as follows ~~~~~~
1. Test Planning
2. Test Analysis
3. Test Design
4. Construction and verification
5. Testing Cycles
6. Final Testing and Implementation and
7. Post Implementation.

Software Testing has its own life cycle that intersects with every stage of the SDLC. The basic requirements in software testing life cycle is to control software testing -- Manual, Automated and Performance.

Test Planning --

This is the phase where Project Manager has to decide what all needs to tested. What is the appropriate budget and resources available etc. Proper planning at this stage would greatly reduce the risk of low quality software. Activities at this stage would include preparation of high level test plan. The Software Test Plan (STP) is designed to define the scope, approach, resources, and schedule of all testing activities. The plan must identify the items to be tested, the features to be tested, the types of testing to be performed, the personnel responsible for testing, the resources and schedule required to complete testing and the risks associated with the plan.

Test Analysis --

Once the test plan is ready and finilized, next stap is to deleve little more into the project and decide what types of testing should be carried out at different stages of SDLC, Do we need or plan to automate, if yes then what is the appropriate time to automate what type of specific documentation is required for testing.

Proper and regular meetings should be held between testing teams, project managers, development teams, and business analysts to check the progress of thiings which will give a fair idea of the movement of the project and ensure the completeness of the test plan created in the planning phase. This will furthur help in enhancing the right testing strategy created earlier. We need to start creating test case formats and test case itself. In this stage we may also need to develop functional validation matrix based on Business Requirements to ensure that all system requirements are covered by one or more test cases, identify which test cases to automate, begin review of documentation, i.e. Functional Design, Business Requirements, Product Specifications, and Product Extarnal etc. We also have to define areas for stress and Performance testing.

Test Design --

In this phase the test plan and cases developed in the analysis phase are further revised, Functional validation matrix is also revised and finilised. In this stage risk assessment criteria is developed. If you have thought of automation then you have to select which test cases to automate and begin writing to scripts for them. Test data is prepared. Standards for unit testing and pass / fail criteria are defined. Schedule for testing is revised ( if necessary) and finilized and the test environment is prepared.

Construction and Verification --

In this phase we complere all the test plans, test cases, complete the scripting of the automated test cases, Stress and Performance testing plans needs to be completed. The development team is also supported in their unitl testing phase. And bug reporting is done as and when the bugs are found. Integration tests are also performed and errors (if any) are reported.

Testing Cycles --

 In this phase we conplete testing cycles until test cases are executed without errors or a predefined condition is reached.

Run test cases --> Report Bugs --> revise test cases (if needed) --> add new test cases (if needed) --> bug fixing --> retesting (test cycle 2, test cycle 3, ............).

Final Testing and Implementation ---

In this phase the remaining stress and performance test cases are executed, documentation for testing is completed / updated, provided and different matrices for testing are completed. Acceptance,load and recovery testing will also be conducted and the application needs to be verified under production conditions.

Post Implementation -- 

In this phase, the testing process is evaluated and lessons learnt from the testing process are documented. Line of attack to prevent similar problems in future projects is identified. Plans are created to improve the process. The recording of new errors and enhancements is an ongoing process.

What is waterfall model ?

waterfall model::

The classic life cycle model or the waterfall model suggests a systematic, sequential approach to software development that begins at the system level and progress through analysis, design, coding, testing, and support.

Software Requirements Analysis:

The requirements gathering process is increased and focused only on software. To understand the nature of the software to be built, the software engineer ("analyst") must understand the information domainof the software as well as required function, behavior, performance, and interface. Requirements for both the system and the software are documented and reviewed with the customer.

Design:

Software design is a stepwise procedure that focuses on four distinct properties of a program: data structure, software design, interface illustration, and procedure (algorithmic) details. The design process transforms into a representation of the software that is evaluated for quality before coding begins. Like requirements, the design is also documented and becomes part of the software configuration.

Code Generation:

 The code generation step translates the design into a machine readable form. If design is performed in a detailed manner, code generation can be accomplished automatically.

Testing:

 Once code has been generated, programl testing starts. The testing process ensure that all statements have been tested, and the functional external; that is, conducting tests to uncover errors and ensure that defined input will produce actual results that agree with expected results.

Supports:

  Software will certainly undergo change once it is delivered to the customer. change will occure because errors occure, and because the software must be adapted to accommodate changes in the extarnal environment (e.g. due to new operating system or peripheral device), or because the customer requires some functional or performance enhancements. Software support/maintenance reapplies each of the preceding phases to an existing program rather than a new one.

Software Testing

software testing is the activity of testing the software application with the intent of finding errors in it.

Another Definitions of Software Testing are as Follow:

* Software testing is an activity aimed at evaluating an attribute or capability of a program or system and determining that it meets its required result.

* Software testing is the process of executing a program or system with the intent of finding errors.

* Software testing is a process used to help identify the correctness, completeness and quality of developed computer software.

* Testing is defined as a verification method that applies a controlled set of conditions and stimuli for the purpose of finding errors.

Regression Testing

Regression testing is the process of retesting a previously tested program following modification to ensure that faults have not been introduced or uncovered as a result.
Testing to ensure that a feature that worked in the previous versions of the software still works and that the software has not taken a step backwards or regressed is called regression testing.

System Testing

System testing is used to testing the attempts to discover defects that are properties of the entire system rather than of its individual components.
System testing is closed to real life experience as it allows verification of the entire software product and validate it according to the original project requirements.

White Box Testing

White box testing is based on an analysis of internal workings and structure of a piece of software. It includes techniques such as branch testing and path testing. It is also known as Glass box testing or structural testing.
White box testing is a complementary approach to functional or black box testing. It involves examination of the internal source of the program. Here, we derive test cases from the programs logic and do not pay any attention to the program functional specifications.

Beta Testing

It is an operational testing processed by potential or existing users/customers at the external site. It is used to determine whether or not a component or system satisfied the users/customers needs and fits within the business processes.
It is starts after alpha testing at the customers or end users site. Beta versions of the software are released to the potential customers or made available for download. As the customers tests the software in a real environment, the developer can not be present here. Failures if any are to be reported by the customers or end users. After receiving such failure reports, developers modify the code and fix the bugs and prepare the product for the final release.

Difference between Alpha and Beta Testing

1.   Alpha- carried out at the developer's site by the potential customers.

     Beta-  carried out at the customer's site by the customer himself.

2.  

Alpha- carried out in a controlled environment.

     Beta- carried out in a real environment.

3. 

Alpha- errors due to strange inputs by the customer are prevented as the developer is looking               over the customer's shoulder and can thus prevent any such errors.

  Beta- failures due to strange inputs by the customer can occur as the developer is not present here.

4.  

Alpha- carried out when the formal testing process is near completion.

    Beta- carried out after alpha testing.

5.  

Alpha- the whole software may be tested or only a specific module of the software may be presented to the customer for testing.

  Beta- various beta releases of the software may be sent to the potential customer. These contain the whole software and may be further improved upon depending upon the customer's feedback.

6.  

Alpha- errors if any can be removed by the developer then and there as the developer is present during the testing.

  

Beta- the customers are expected to report failures if any so that the developer's can work to rectify them.

Alpha Testing

Alpha testing is conducted at the developers site by the customer in a controlled environment with the developer looking over the customers shoulder, thus preventing errors due to unexpected or strange inputs by the customer. This testing starts when the formal testing process is near completion, but it is not necessary that the complete software might be tested.The developer might even get a particular, important module tested by the customer here.

Explain Process Control block (PCB)

Explain Process Control block (PCB)

Process Control block is used for storing the collection of information about the Processes and this is also called as the Data Structure which Stores the information about the process. The information of the Process is used by the CPU at the Run time. The various information which is Stored into the PCB as followings:

1) Name of the Process.

2) State of the Process. Means Ready, Active, Wait.

3) Resources allocated to the Process

4) Memory which is provided to the Process.

5) Scheduling information.

6) Input and Output Devices used by the Process.

7) Process ID or a Identification Number which is given by the CPU when a Process Request for a Service.

What is GSM ?

GSM

What is GSM?

GSM (Global System for Mobile communications) is an open, digital cellular technology used for transmitting mobile voice and data services.

What does GSM offer?

GSM supports voice calls and data transfer speeds of up to 9.6 kbps, together with the transmission of SMS (Short Message Service).

GSM operates in the 900MHz and 1.8GHz bands in Europe and the 1.9GHz and 850MHz bands in the US. GSM services are also transmitted via 850MHz spectrum in Australia, Canada and many Latin American countries. The use of harmonised spectrum across most of the globe, combined with GSM’s international roaming capability, allows travellers to access the same mobile services at home and abroad. GSM enables individuals to be reached via the same mobile number in up to 219 countries.

Terrestrial GSM networks now cover more than 90% of the world’s population. GSM satellite roaming has also extended service access to areas where terrestrial coverage is not available