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I was wondering if a Waterfall model is an incremental model because technically each phase of the Waterfall model adds on a little more.
Thus saying this I have read from quite a few different websites that it is not incremental.
Can someone please provide examples of both Iterative and Incremental models as I find the 2 a bit confusing?
In Waterfall, you do all of the analysis, then you do all of the design, then you do all of the coding, then you do all of the testing. It is not incremental because at each phase everything from the previous phase has to be complete. The problem with Waterfall is that there is no feedback throughout the process. If requirements change or some assumption turns out to be wrong, these usually don't get discovered until after the all the work is done and the product is delivered to the customer for the first time. At that point it is often more difficult and costly to make changes.
In an incremental model, you do a little analysis, a little design, a little coding and a little testing, then, after getting feedback from the customer, you go back and do a little more analysis, a little more design, a little more coding, a little more testing etc. So the product is built incrementally over many iterations of this process. The idea is to get feedback early and often so that you aren't wasting a bunch of time and effort building something that the customer isn't ultimately going to be happy with. Agile and Scrum are examples of incremental models.
Not incremental.
The waterfall model assumes that you are God and therefore can predict everything. Also that the customer knows what they want. Often at least one of the above is false.
Iteration: think small waterfalls, which better allows for altering the Big Plan to fit a changing reality.
Incremental: very often seen in conjunction with iterative models. Start with a core and add functionality rather than delivering the whole thing at once.
As for examples, most anything with [agile] (http://en.wikipedia.org/wiki/Agile_software_development) in it will be both incremental and iterative.
I would agree with Ryman, Waterfall model is neither iterative or incremental. You can find clear explanation of iterative model and incremental model on this site.
As shown on the site, in a waterfall model you would have the whole picture at once, though it may or may not look like the Monalisa.
A Waterfall model is neither Incremental nor Iterative because it develops the whole system at once, without any increments or iterations.
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First of all sorry for the codeless question, but I like to clarify one thing.
I have a senior developer in a team who is actively pushing for code quality - merge request reviews, no crappy code and similar. But most of the other guys in the team has - get shit done mentality. Me as a business guy, I do not check the code at all, but If I would not have that guy who cares about the quality - in my opinion we would hit some heavy refactoring cycles at some point.
But of course there is a downside for caring carefully about the quality too much - it just takes time to do that. Maybe we will have to throw a lot of beautiful code when we will have to pivot as business needs changes.
Two questions: a) how do you keep the quality of your product? What practices do you use? b) Where is the line of caring about code quality enough (not too less and not too much)?
Code quality is important independent from whether you develop agile or not. You are absolutely right that quality improvement requires additional time. Most people fail because they spent their time in larger blocks ('refactoring projects') to more or less clean up code in arbitrary places with the objective of reducing the number of quality issues as much as possible.
The process I advise to use is to follow the boy-scout rule of always leaving the code that is changed a bit cleaner (better) than it was before. That means whenever you change a function, procedure, method or other code unit, fix the quality problems in it. The advantage is that you already understood the code (because you had to change it anyways) and it is going to be tested (because you need to test your original change). That means the additional effort for quality improvement (adding a comment, improving identifiers, removing redundancy, ...) is very low. In addition, you are improving only code that you are working with and don't waste time improving code that is never touched anyway.
Following the boy-scout rule ensures that the quality does not decrease, but instead steadily increases over time. It is also a reasonable level of 'caring'. I wrote some more about this here. In addition you need a good quality analysis tool like Teamscale that can reliably differentiate between legacy problems, new problems and problems in the code you recently changed.
Get and enforce a good unit testing framework and back it up with automated integration testing.
As for Agile I found the morning 10 minute scrums to be useful, but the end-of-sprint meetings tended to be long.
I made good experience with Sonar Qube a tool we are using for static code analysis. So we can keep track of
code smells, etc. in our code base. Another point is, that fixing issues can be planed in sprints! An IDE integration is available as well!
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I have been doing TDD for the past 3 years. We were a small company, and we had very solid support for most aspects of the agile process from management. Everyone on the development team was sold on the process. And thus, the upfront investment it usually takes to build fixtures was accepted knowing it would pay off along the way. (Code that starts an http server, code that populates sql databases before tests, etc). Documentation mostly happened in the tests and help requests were usually presented in the form a failing test.
Now I moved to a bigger company, and while management is supportive of the Agile process, teammates are a mixed bag, some of them see it useful, some of them do it because of management and some don't see the value. It's been a challenge to convince people to spend some time building fixtures or to convince a team member the best way for me to help him if he took the time to write a failing test.
So what do you think is the best way to sell TDD to a hesitant teammate? The objections are usually : 'It's an unneeded cost', ' we can always write tests after the fact for parts that are important', 'it's a buzz word, teams pick it up and then it falls to the side as the heavy grind begins' etc.
"the best way to sell TDD to a hesitant teammate"
You can't. Don't waste time "selling".
Instead, invest time in "proving".
Just do it. Be successful. When people ask what the secret of your success is, then reveal the TDD. Not before.
simple -- maintainability. TDD gives you the ability to make changes, and see where those changes affect the rest of the code. The larger the code base, the more imperative it is that there be tests to validate any new changes.
correctness. Although tests can themselves be broken, eventually they reach a point where they make sure the components are doing what they are supposed to. The better the developer, the faster that is.
another advantage is that TDD informs the design of the components in the system. If you are trying to test something, and the test is too complicated, it probably means you need to break the problem down into smaller parts...
to sell it to people, you say that in the long run it makes adding new features cheaper, and reduces the risk of breaking existing functionality. So it reduces cost.
For the hesitant teammate, be patient, wait for an opportunity, then pounce. In software development there will undoubtedly be an problem where TDD would have prevented or mitigated the problem. Be on the lookout for such an opportunity. Work with him/her to create a test(s) that should have been developed from the beginning. However, make sure you craft your message in such a way to not embarrass your teammate.
I agree with S. Lott, you can't "sell" them you need to show the value.
One of the most effective ways to do that is with pair programming. Granted you have another "sell" problem convincing people that pairing is an effective approach, but after some time you may convince/convert a developer or too.
TDD was a tough concept for me initially, but now I can't imaging programming any other way.
I think Joel's post explains very well why testing is A Good Thing™.
I don't think he ever uses the phrase "TDD", but it's got some great info.
Show them this site: WeDoTDD.com - actual company team use cases. Those who are successfully practicing TDD in real companies.
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Estimating how long any given task will take seems to be one of the hardest parts about software development. At my current shop we estimate tasks in hours at the start of an iteration, but once the task is complete we do not use it to aide us in future estimations.
How do you use the information you gather from past estimations to refine future ones?
By far one of the most interesting approaches I've ever seen for scheduling realistically is Evidence Based Scheduling which is part of the FogCreek FogBugz 6.0 release. See Joel's blog post linked above for a synopsis and some examples.
If an estimate blew out, attempt to identify if it was just random (environment broke, some once off tricky bug etc) or if there was something that you didn't identify.
If an esimate was way too large, identify what it was that you thought was going to take so long and work out why it didn't.
Doing that enough will hopefully help developers in their estimates.
For example, if a dev thinks that writing tests for a controller is going to take ages and then it ends up taking less time than he imagined, the next estimate you make for a controller of similar scope you can keep that in mind.
I estimate with my teammates iteratively until we reach consensus. Sure, we make mistakes but we don't calculate the "velocity" factor explicitely but rather, we use gathered experience in our new estimation debates.
I've found that estimating time will get you so far. Interuptions with other tasks, unforseen circumstances or project influences will inevitably change your time frames and if you were to constantly re-asses you would waste much time managing when you could be developing.
So for us here, we give an initial estimation based on experience to the solution for time (we do not use a model, I've not found one that works well enough in our environment) but do not judge our KPIs against it, nor do we assure the business that this deadline WILL be hit. Our development approach here is largely reactive, and it seems to fill the business' requirements of us very well.
when estimates are off, there is almost always a blatant cause, which leads to a lesson learned. Recent ones from memory:
user interface assumed .NET functionality that did not exist (the ability to insert a new row and edit it inline in a GridView); lesson learned is to verify functionality of chosen classes before committing to estimate. This mistake cost a week.
ftp process assumed that FtpWebRequest could talk to a bank's secure ftp server; it turned out that there's a known bug with this class if the ftp server returns anything other than a backslash for the current directory; lesson learned is to google for 'bug' and 'problem' with class name, not just 'tutorial' and 'example' to make sure there are no 'gotchas' lurking. This mistake cost three days.
these lessons go into a Project Estimation and Development "checklist" document, so they won't be forgotten for the next project
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Some developers when given a task go straight into the IDE and start coding with very little design. They may have an idea of where the application is going as they are coding. I am 1 of these developers. I do this because I feel that if I spend a lot of time designing my application delivery time will be much higher as compared to if I just sit and code away the ideas in my head. My question is that how does application design effect the delivery time of the project and does it have a big advantage over coding the agile way?
Give you a example, when you want travel,
If your destination is near or in your town, you can start right away.
When you want travel to another country, you need package your self first.
Design is for preparation, without it , you cannot go too far(or go the wrong way).
It is not a black and white situation: for some projects it is much better to jump in and start coding, for some it's better to have an extensive planning stage, and for others it is not clear cut.
If the project is small and simple enough that only a single developer is working on it, and how to build it is obvious enough that they can imagine every aspect of it in their head, then they can very well jump in and start designing.
The need for more extensive planning comes about when you have multiple developers, or when the project is large and complicated enough that a developer cannot know everything possible about how it will work from the outset, because it is too complicated to know all aspects of it in your head.
What you describe only works well if you are writing something well well understood and contained. If it is similar to other software you've written you don't need a new design because you can just re-use the old one. however, if it is something totally new, designing on the fly will get expensive. You'll find yourself rewriting too much of the code or worse, stuck with a poor architecture which slows you down. Likewise, if you need your code to be extensible, planning ahead is necessary. If you need it to work with components from other people, planning ahead is necessary.
This approach only really works well if you are working on your own. If you have to work within a team of people, it is important to have a good plan so that everyone else knows what you think is the end goal. This doesn't reduce creativity it just allows you to make sure everyone is on the same page, and it reduces the opportunities for confusion.
(source: yang.id.au)
Just to add a line of thought to your equation scenario, let me contribute this little bit hereafter: I work in a business called YES INTERNATIONAL CORPORATION (www.yesintl.com.au) Sometimes, it does happen that developers may have developed something before so in that case the design is already in the mind. For example, I have developed database solutions in the past which makes us a very fast delivering corporation compared to our competition when I sit down and start developing a project. More experience will make you super perfect as the time goes by... I hope this helps... Andy
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Why should companies invest in refactoring components, though it is not going to add any new feature to the product ?
I agree it is to clean the code, fix bugs and remove dead code - but what is the take ??
Maintenance. It will reduce your maintenance costs significantly. There is no comparison between fully factored code and the junk that sits in most companies repositories. The latter is virtually worthless, while the former is gold.
It depends who you ask. A non-technical manager may say there is no need. A support developer would say that it would help keep the maintenance costs down.
Refactoring needs to be a part of your every-day job. You constantly refactor your code to make it more readable/maintainable/robust/reusable, etc.
Your code is a living document. If it doesn't change over time, it becomes stagnant.
Invest in testing. Invest in refactoring. Invest in writing good code.
maintenance. Sometimes, a project gets to big or with too many "fast" patches to be further expanded. You just have to sit down calmly and clean and refactor.
While the other answers are all true the power of Refactoring is that it allows you to change the design of your code with predictable results. The biggest problem of maintenance is that it is virtually impossible to anticipate all requirements for complex applications.
Most of these can be dealt with by adding a new feature like a new report or command. But other will require part of your application to be redesigned. This is where refactoring and it's sibling unit-testing comes into play. By using refactoring techniques you can make needed design changes safely.
It is not a cure all technique but another tool that improves the quality of your code. (stuructured programming, object-orientation, etc).
To start off with: Refactoring is a tax. If the code works, then you are spending time fixing code that already works, I can see the business types looking quizzical now. A saying I like is "Legacy is another word for code that works."
Now there are many problems with a growing code base that need to be addressed before you start to spend more time maintaining the code that developing features.
Personally I like the "No Broken Windows" philosopy.
If it ain't broke don't fix it.
But if you need to start fitting the components into new unpredictable requirements then it often makes sense to identify the bits you can extract and reuse. You need to be certain that your changes are introducing unexpected bugs - so you'll need good test coverage.