Why Does Software Have Bugs???
Why does software have bugs????
* Miscommunication or no communication - as to specifics of what an application should or shouldn’t do (the application’s requirements).
* software complexity - the complexity of current software applications can be difficult to comprehend for anyone without experience in modern-day software development. Multi-tier distributed systems, applications utilizing mutliple local and remote web services applications, data communications, enormous relational databases, security complexities, and sheer size of applications have all contributed to the exponential growth in software/system complexity.
* programming errors - programmers, like anyone else, can make mistakes.
* changing requirements (whether documented or undocumented) - the end-user may not understand the effects of changes, or may understand and request them anyway - redesign, rescheduling of engineers, effects on other projects, work already completed that may have to be redone or thrown out, hardware requirements that may be affected, etc. If there are many minor changes or any major changes, known and unknown dependencies among parts of the project are likely to interact and cause problems, and the complexity of coordinating changes may result in errors. Enthusiasm of engineering staff may be affected. In some fast-changing business environments, continuously modified requirements may be a fact of life. In this case, management must understand the resulting risks, and QA and test engineers must adapt and plan for continuous extensive testing to keep the inevitable bugs from running out of control.
* time pressures - scheduling of software projects is difficult at best, often requiring a lot of guesswork. When deadlines loom and the crunch comes, mistakes will be made.
* egos - people prefer to say things like:
no problem
piece of cake
I can whip that out in a few hours;
it should be easy to update that old code
instead of:
that adds a lot of complexity and we could end up
making a lot of mistakes
we have no idea if we can do that; well wing it
I cant estimate how long it will take, until I
take a close look at it
we cant figure out what that old spaghetti code
did in the first place
If there are too many unrealistic no problems;, the
result is bugs.
* poorly documented code - it’s tough to maintain and modify code that is badly written or poorly documented; the result is bugs. In many organizations management provides no incentive for programmers to document their code or write clear, understandable, maintainable code. In fact, it’s usually the opposite: they get points mostly for quickly turning out code, and there’s job security if nobody else can understand it (’if it was hard to write, it should be hard to read’).
* software development tools - visual tools, class libraries, compilers, scripting tools, etc. often introduce their own bugs or are poorly documented, resulting in added bugs.
Re: Why Does Software Have Bugs??
What Are Some Recent Major Computer System Failures Caused By Software Bugs.* According to news reports in April of 2004, a software bug was determined to be a major contributor to the 2003 Northeast blackout, the worst power system failure in North American history. The failure involved loss of electrical power to 50 million customers, forced shutdown of 100 power plants, and economic losses estimated at $6 billion. The bug was reportedly in one utility company’s vendor-supplied power monitoring and management system, which was unable to correctly handle and report on an unusual confluence of initially localized events. The error was found and corrected after examining millions of lines of code.
* In April of 2003 it was announced that the largest student loan company in the U.S. made a software error in calculating the monthly payments on 800,000 loans. Although borrowers were to be notified of an increase in their required payments, the company will still reportedly lose $8 million in interest. The error was uncovered when borrowers began reporting inconsistencies in their bills.
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