Software Development Life Cycle (SDLC)

1. System Information/Engineering and Modeling
a.The initial proposal phase to understand and identify the project requirements and main features proposed in the application
b. By the end of the study the entire client systems, the team furnishes a document that holds specific recommendations for the candidate system. Out Put of this phase

• A rough estimation of efforts and prices for entire project
• A Rough Schedule for entire phase
• Initial business functions in the project

2. System Requirement Analysis & Specification
The objective of this phase to identify and document the user requirements for a proposed system.This phase contains complete information of function, information of the domain for the software,behavior,performance,Interfacing.Out put of this phase is

• An estimate for effort or price for remaining project phases(Design, Development, Testing Deployment, Support)
• Details Schedule of the remaining Phases(Design, Development, Testing, Deployment, Support)
• The final functional specification and analysis for other phases

3. System Analysis and Design
a. This process of designing exactly of the specifications are to be implemented
b. How the software to written, including object model with properties and methods, Database Designing,client server architecture. Out put of this Phase A Final Design Specification
4. Code Generation
a. Design Must be Formatted in to machine readable format
b. With respect of the application the right programming language is used,

• A Beta version of application
• Preliminary Manuals and user document
• Preliminary Technical Documents

5. Testing
Once code is generated Program testing begins.Different testing methodologies are available to unrevealed the bugs.Out put of this phage

• A Final version of complete application
• A Final Manual
• A Final Technical Document

6. Deployment & Maintenance
In This software ready to deploy in customer place, maintenance period starts for the application.Application should create accept the changes in this phase

Quality Control & Quality Assurance

Quality Assurance
All those planned and necessary ideas to provide adequate confidence that the product/service will satisfy the given requirements of quality
Quality Control
All those necessary steps taken for fulfilling the requirements of quality

Some Major Computer System Failures Caused by Bugs

1. In August of 2006 a U.S. government student loan service erroneously made public the personal data of as many as 21,000 borrowers on it's web site, due to a software error. The bug was fixed and the government department subsequently offered to arrange for free credit monitoring services for those affected
2. A September 2006 news report indicated problems with software utilized in a state government's primary election, resulting in periodic unexpected rebooting of voter checking machines, which were separate from the electronic voting machines, and resulted in confusion and delays at voting sites. The problem was reportedly due to insufficient testing
3. Software bugs in a Soviet early-warning monitoring system nearly brought on nuclear war in 1983, according to news reports in early 1999. The software was supposed to filter out false missile detections caused by Soviet satellites picking up sunlight reflections off cloud-tops, but failed to do so. Disaster was averted when a Soviet commander, based on what he said was a '...funny feeling in my gut', decided the apparent missile attack was a false alarm. The filtering software code was rewritten

When to Stop Testing

It's difficult to determine exactly when to stop Testing.The following are some of the cases which can help to decide when to reduce/stop Testing
1. Deadlines(Release/Test Deadlines etc)
2. Test cases completed with certain percentage passed
3. Test budget depleted
4. Coverage of code/functionality requirements reaches a specified point
5. Bug rate falls below a certain level
6. Beta or Alpha testing period ends

Inadequately Tested Software Negative Impacts

It is difficult to test software products, as evidenced by the problems we find in our software every day. The customer risks of not adequately testing software can be as minor as user inconvenience or as major as loss of life. Not only are there customer (end-user) risks for inadequately tested software, there are also corporate risks. Especially for mature products, an inadequately tested product can have serious negative consequences for a company

Software Testing Axioms

1. It is impossible to test a program completely
2. Software testing is risk based exercise
3. Testing cannot show that bugs don't exist
4. The more bugs you find, the more bugs there are
5. Not all the bugs you find will be fixed
6. Product specifications are never final

Software Testing

Intentionally finding errors from the software is called testing. Errors may be functional errors or usability errors or excess functionality which is not defined by client. Simply means testing the Software to find and report defects. It gives an assurance that the end product is as per customer requirement specification
Goal of Software Testing
Quality in software product in terms of functionality, user friendly
Testing Operators
Tester, Test Lead, QA Manager, Project Manager, Developer and Client
Test/QA Team Lead
Coordinates the testing activity, communicates testing status to management and manages the test team
Testers
Develops test script/case and data, script execution, metrics analysis, and evaluates results for system, integration and regression testing
Test Build Manager/System Administrator/Database Administrator

• Delivers current versions of software to the test environment
• Performs installations of application software, and applies patches (both application and operating system)
• Performs set-up, maintenance, and back up of test environment hardware.

Technical Analyst & Test Configuration Manager

• Performs testing assessment and validates system/functional test requirements
• Maintains the test environment, scripts, software, and test data