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As developers and as professional engineers have you been exposed to the tenants of Extreme Programming as defined in the "version 1" by Kent Beck.
Which of those 12 core principles do you feel you have been either allowed to practice or at least be a part of in your current job or others?
* Pair programming[5]
* Planning game
* Test driven development
* Whole team (being empowered to deliver)
* Continuous integration
* Refactoring or design improvement
* Small releases
* Coding standards
* Collective code ownership
* Simple design
* System metaphor
* Sustainable pace
From an engineers point of view I feel that the main engineering principles of XP arevastly superior to anything else I have been involved in. What is your opinion?
We are following these practices you've mentioned:
Planning game
Test driven development
Whole team (being empowered to
deliver)
Continuous integration
Refactoring or design improvement
Small releases
Coding standards
Collective code ownership
Simple design
And I must say that after one year I can't imagine working differently.
As for Pair programming I must say that it makes sense in certain areas, where there is a very high difficult area or where an initial good design is essential (e.g. designing interfaces). However I don't consider this as very effective. In my opinion it is better to perform code and design reviews of smaller parts, where Pair programming would have made sense.
As for the 'Whole team' practice I must admit that it has suffered as our team grew. It simply made the planning sessions too long, when everybody can give his personal inputs. Currently a core team is preparing the planning game by doing some initial, rough planning.
I consider myself lucky, all except "Pair programming" we can do it, but only to solve big issues not on a day-to-day basis. "Collective code ownership" is hard to achieve as well, not doing pair programming we tend to keep the logical next user stories from iteration to iteration.
Whole team (being empowered to deliver)
Small releases
Coding standards
Collective code ownership
But then, I do work in a mission-critical development team that's quite conservative. I don't necessarily thing XP is a good way to develop, you must find a way that's right for you and ignore the dogma.
We've done everything except small releases and it's been great. I can't imagine working any other way. From my experience, the tenets I value most are:
Continuous integration (with a solid test suite).
Collective code ownership.
TDD
Team empowerment and decision making.
Coding standards.
Refactoring.
Sustainable pace.
The rest are very nice to have too, but I've found that I can live w/o pairing so long as we have TDD, collective ownership, and refactoring.
Pair programming[5]
It is hard to convince management of this aspect. But I have found this is doable when an engineer gets stuck or we have an engineer who is new to a technology or effort.
Planning game
Yes.
Test driven development
Easy sell to management. However the hard part of some management is adding in more time. A lot of managers believe that Extreme and Agile programming will save them time. They don't save time to deliver you something. In fact, the testing constant requirements gathering adds effort. What it does do, is it gets the customer what they want faster.
Whole team (being empowered to deliver)
Definitely, this is an amazing facet to Xtreme.
Continuous integration
At the end of each iteration (sprint) full integration occurs. Daily full integration does not occur.
Refactoring or design improvement
Your first effort is rarely the best. So yes, I find Xtreme constantly yields better and better solutions.
Small releases
I find that given the infrastructure and resources that can lengthen the suggested length of an iteration of 1 or 2 weeks. A lot of this depends on where you are deploying to. If you system is being deployed to a production environment, formal systems and stress testing can add a lot of overhead. So in this environment, we go with iterations lasting a month or even 2 months. If the system is being deployed to a development area and has not been deployed to production, even something as tight as an iteration lasting 1 day can be doable.
Coding standards
Pair programming for new team members can promote this. Code reviews also can help here. A lot of this depends on how long you have been working with each other.
Collective code ownership
I haven't found that Xtreme really helps here. Everyone naturally falls into certain areas of the code base. So people get ownership of things they spend a lot of time with. This can actually be a good driver as good software engineers will take pride in what ever they write this way.
Simple design
Short iteration cycles do in fact promote a simple design. It needs to be maintainable for the short releases.
System metaphor
Not sure what is meant here?
Sustainable pace
Velocity of a team is a task that can only be acutely estimated with proper metrics. Metrics need to be kept on task estimates and task completions durations.
Related
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After working Scrum(ish) in a previous workplace, I am trying to implement it in my new place of work for a brand new project (I am no scrum expert). We have some pre-requisites to code before we can begin working on the stories (which are being groomed in the mean time). Things like database design, api design, etc. We plan to use two week iterations and it's just not clear to me how the first one (or two) can provide something useful to the customer and "potentially shippable" if we first have to "lay down some groundwork" ? Any ideas on how to treat this?
What you are experiencing is very typical of new teams wanting to move to Scrum where they are coming from more of a traditional process. Adapting to Scrum is very, very hard and we always say this, and the reason for this is there needs to be many mindset changes.
The first change the team should understand is that when bringing a PBI (requirement) into a Sprint, it only a well defined requirement with nothing else. This means there is no designs, database schemas or API's for the requirement. The team has to do all of this in the sprint, plus build and test the requirement.
If you are new to Scrum, you most probably are squirming in your seat thinking it cannot be done. You are likely right for now, but this is where the hard work comes in ... changing the way teams work. This is hard.
Some pointers :-
Small Requirements - Most teams suffer from poor, ambiguous requirements which previously took days to design, build and test. The art is to learn to break these EPIC requirements down into smaller incremental requirements where each one builds upon the previous, but explicitly adds business value. Now, I am going to be blunt here ... this is the biggest challenge for most teams. Personally, I have been training/coaching Scrum for a number of years now have not found any feature that cannot be broken down into small requirements with an average estimate of 2-3 days to fully complete.
Team composition - The team needs people in it with all the skills necessary to design, build and test the PBI. They should not have dependencies on other people outside of the team. Having dependencies, cripples teams but it highlights to management there are not enough people with the specialised skills.
Sprint Planning - Sprint planning should be used to do high level designs and discuss how the team is going to tackle delivering each requirement. Many teams waste their sprint planning by clarifying weak requirements and debating the requirement. This is a sign of weak requirements and it should be addressed. Sprint planning is about discussing How to build/test a PBI and not What.
Coach - I would really recommend you hire an experienced contract coach/consultant to get you going and do things right. Trying to do this by yourself, just leads to a world of unnecessary pain.
Architecture - At the inception of the project, there is nothing wrong for the team and architects to spend a day or two brainstorming the macro architecture of the product and discussing the technologies to be used. However, when it comes to new requirements they are designed and adjusted into the product. This sounds hard, but with the correct software engineering patterns using SOLID principles, well defined patterns as well as strong Continuous Integration and Unit Testing. The risks of a bad architecture are eliminated. There is not question that the team should have a member in it that has the skills to design an architect the new requirements. [There is lots of evidence on the web that an evolving architecture with re-factoring results in a better application than a big upfront architecture - but that another debate]
Application Lifecycle Management - Invest in strong ALM tooling with CI, unit testing, test lab, continuous deployment. Having the right tools for the team allows you to deliver quickly, and a lack of these totally cripples you. CI with automated testing is essential for an incremental product as there is fast and constant change and you want to protect that a change does not break a previous requirement.
ScrumBut - Ken and Jeff no longer support the use of the term ScrumBut as it is perceived as elitism and often comes across as belittling. Instead it is preferred that teams are on the journey to implementing Scrum and helping them through coaching.
Welcome to your journey into Scrum, hang in there as it is very hard initially. Once you fully "get it", then you and your company will be really happy that you did.
In an ideal world, Technical pre-requisites should be factored into the estimate of each story and you should only implement "just enough" to complete the story. See "Do The Simplest Thing That Could Possibly Work"
Why do you need to design the API or the Database? Try to avoid Big Up front design. Avoid building Frameworks up front, apply YAGNI
It's hard for you to understand how you could ship something in two weeks because you have the cart before the horse; that is, your priorities are wrong. The important thing is delivering customer software - not building databases or API designs.
This is a trade of against long term productivity and you should avoid accruing too much technical debt. Many Agile methodologies would argue that up-front work like this will be wrong and therefore should be avoided to minimise waste. Lean software recommends defering decisions to the Last Responsible Moment.
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Our team is debating whether we want to become Agile or not. None of us are really fluent in Agile. I'd like some thoughts on when Agile works well, and when it doesn't.
To give a little background, we are a small group of developers, six in total. We have far more work that we can handle. Our priorities change often. What is a high priority today, may not be tomorrow. We have many applications to create and maintain. We have started to dabble in Agile practices to the extent that we have daily scrums and two-week Sprint cycles.
If you need more information to answer this, please feel free to ask.
Thanks.
Ralph Stacey's complexity matrix is commonly used to illustrate the sweet spot for Agile:
(source: typepad.com)
For simple projects (where both the requirements and the technologies are well known), the predictability is high so a predictive methodology (waterfall) works well.
For complicated and complex projects (and the vast majority of IT projects are), predictability is low and a predictive methodology won't work, an adaptive approach should be preferred. This is where Agile works well.
When both the requirements and the technologies are unknown, you're close to the chaos and the odds of failure are very high, regardless of the methodology.
I'm speaking only from experience; YMMV.
My team was unsuccessful at making agile work. IMO, it was because:
The very first time the dev team
would hear about a project, it was in
the form of a requirements document
and a deadline.
Stakeholders were often reluctant
to take time to look at the result
of a sprint's work, thus they would not take action between sprints if they thought the project was headed in the wrong direction.
When we showed stakeholders our work,
they generally just OK'd it. They
would talk about what they would
like, to which we would reply "That
can be done in about X amount of
time," to which they would reply,
"Well no need to go over the deadline
for that."
The deployment process was long and
complicated, discouraging frequent
deployments. So in practice, we
often deployed things when a 2-month
project was done, not at the end of a
sprint.
Our sprint planning meetings were
long and inefficient.
It seems everyone was confused about what scrum is (and about what our process was), except for the scrum evangelists.
So I'm pretty sure we were doing it all wrong. Don't you do it wrong, too.
Some things that have sped us up, which we continue to use:
automated builds that work on
everyone's machine (HUGE help!)
a formal arrangement for our code
repository
learning how to apply apply
abstraction mechanisms to UI code
refactoring
unit and integration tests
continuous integration
I guess you could say that our code is more agile, though our methodology is less agile. Whereas before we could not keep pace with demands, now we can.
(I'm not saying agile is bad; I'm just reporting my experience. Also, please understand that I do not choose what methodology we use.)
Reposting a related answer of mine:
The discussion is usually agile vs. waterfall, right? I am linking an article, but it is in Portuguese, so I'll try to transmit some of its ideas:
Waterfall is like chess. You think and plan a lot, try to foresee every possible issue as soon as possible. There's a lot of planning, but makes sense only on stable and well-known domains, where change isn't much expected.
Agile is like soccer (or many collective sports): decisions are made in-game and should be done fast. There's no much time to analyze every consequence. It is "ideal" for dynamic and unstable domains, where change is always expected (web applications, for instance, tend to fall in this category). Another point to note is: even if you have the best players, if they don't do well as a team, you won't be the winner.
IMHO, Scrum would be useful, because:
Once every two weeks (or every month, depending on iteration time) you'll be able to see what's working or not. And this is very valuable, specially as an "amateur" team, which is expected to be learning and finding things out much more constantly.
As amateurs, you probably won't be able to foresee everything (and that's something agile embraces)
There's more space for sharing experience (stand-up meeting, retrospective, and even planning meeting). And you share REAL experience (you must write code every week rather than just plan)
It appears your priorities are changing far too frequently for either methodology Agile or Waterfall. With priorities changing frequently, you are likely churning in and out of projects leaving a lot of them partly done. The Agile alway be ready to release may help. It has been my experience that getting a methodology in place will improve productivity.
Your situation reminds me of a project I worked on. The developer on the project asked one question at the start, "Do you want me to be do it right or be responsive?" I was on the project when it was two years into a six month project. One week the same functionality was implemented Monday, Wednesday, and Friday. Tuesday and Thursday were spent removing the functionality.
I would suggest you start adopting practices from Agile. Scheduling a short sprint period could help with changing priorites. It may be easier to maintain priorities for a period of a week or two and may make it easier to stabilize priorities. You will also need a backlog (sounds like you have a large one already).
Management may be more willing to hold off new priorities if you can slot them into a sprint in a week or two. You will also be able to identify the priority tradeoffs. If you add something to the next sprint, what will be removed.
Consider having part of the team working Agile while the others maintain the status quo. Rotate one team member each sprint as you are gaining experience. Consider having the whole team participate in a daily stand up status meeting, and the post sprint review. Once you have demonstrated increased productivity and returns to the company you should be able to increase the amount of work being done using your methodology.
Agile is a adaptive methology. Expect to be making major changes to your methodoly for the new year or two. Eventually, you should reach a stage where you are fine tuning.
In my experience, you absolutely need the following for agile (XP or Scrum at least) to work. Without these prerequisites you are likely to fail. Hard.
Team must be stable and 100% dedicated to this.
Team must be colocated in one workspace.
Customer/product owner must be available on site at all times.
Support from management. This means providing funds and courage to ensure the points above.
Give these points, you can probably tackle anything as long as you keep to the values.
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Looking for work at the moment, I'm seeing a lot of places asking for Agile experience, but until I get a job with a team that is using Agile, I suspect I'll never get the experience.
Is it possible to adopt Agile methodologies with just one person?
Sort of answering my own question, there's similar questions at :-
https://stackoverflow.com/questions/1407189/can-agile-scrum-be-used-by-1-or-2-developers
(I guess I should get better at searching.)
You seem to be coming at this from a work experience point of view; if you are looking to build relevant experience to get you a job on an agile project I would probably think a little more laterally.
Firstly could you work with others, maybe on an open source project? That would be a good opportunity to try out agile methods with others who may have more experience.
Secondly, you could look at using some of the common techniques or tools, even if it's just to learn how the tools work - e.g. you could set up a continues integration server to run builds and unit tests when you check in code. If you are working on your own you won't gain much in terms of productivity by doing this but you would gain some skills and have something relevant to say to future employers which would indicate you are committed to the agile style.
Yes
Check out PXP or Personal Extreme Programming.
http://portal.acm.org/citation.cfm?id=1593127
Summary from the paper:
Personal Extreme Programming (PXP) is
a software development process for a
single person team. It is based on the
values of Extreme Programming (XP)
i.e. simplicity, communication,
feedback, and courage. It works by
keeping the important aspects of XP
and refining the values so that they
can fit in a lone programmer
situation. PXP can still be refined
and improved. It is in the tradition
of XP practitioners to vary XP to
encompass whatever works. We hope
that PXP inherits these pragmatic
roots, as well. Giving up XP tenets
like pair programming is not
necessarily a tragedy. We still
believe that following XP strictly is
a more effective way to pursue
multi-person projects. But we are also
convinced that many of the XP
practices and methods can be applied
to individual work. The PXP
approach tries to balance between the
"too heavy" and the "too light"
methodologies. PXP will inject the
right amount of rigor for the
situation without overburdening the
team with unnecessary bureaucracy.
Yes - it is possible to do many agile practices as an individual.
If you already know how to do these, you can do them as a sole developer:
test-driven development - great place to start
refactoring
continuous integration
doing the simplest thing that could possibly work (and evolving it through refactoring)
automated deployment
planning meetings (a team of one plus customer)
Things you can't do on your own:
pair programming
CRC/RRC workshops (... you'd have to talk to yourself quite a lot)
Pair programming would be hard this way :)
Let's check Agile Principles:
Individuals and interactions over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan
You can do all of those things even while working on some personal project alone. You can use also GTD while working alone, you can develop your product through iterations, you can adopt timeboxing, you can ask some family members or friends to do usability tests with you (and this works really well).
As a conclusion, you can really get tons of Agile experiences alone. I strongly recommend you to read some books first tho, as some of principles can be easily misinterpreted.
Some aspects can be done alone: running a product backlog and using a task board come to mind. See what the secretGeek is doing.
Of course some cannot: pair programming, scrums etc...
I recently interrupted a big project. It was a medical software project. While working on it, I realized some patterns about solo programming. I want to share my experiences here:
Your software's working logic must always reflect the real world. You catch fish with fishing rod, not baseball bat; so forget it.
Always start building from the project element to which all other elements refer. That makes sense if you think that like the function in a software project which is called at most. That might be database modeling. It would be useless if you model data access layer first, before modeling database.
Never mind changing variable names. That's the most written entry in a programmer's diary; so no need to be ashamed.
Methodology changes the world. Make worth of it. Make every single logical process with a function or procedure. When project gets huge you will understand thats the best way.
If you're not designing a language compiler in assembly do not hesitate using huge procedure call chains in which one calls another and that calls another and so on. Use methods everywhere, nearly resemble every single entity with classes and be modular.
Modularity is everything. Set modularity your primary goal. Have i said it is everything meanwhile?
Last word for beginning the project. If you're building an apartment you install main entrance at last. But when using, you enter the building from entrance. Be aware.
These are some of my design principles I learned and learning day by day. I hope having been useful. Do your best.
While some Agile practices are directly targeted at more than one person teams, they are just practices, they are just a mean, not an end. I mean, Agile is not about doing pair programming, stand up meetings, etc. Agile is about maximizing the customer value while minimizing waste to provide the most optimal ROI. Agile is business oriented, practices are just a way to achieve this goal in a given context. So, back to the initial question, it's definitely possible to adopt Agile practices (that make sense in your context) to maximize the delivered value: continuous planning, limiting Work In Progress, Stop-the-Line culture, time boxing, high quality, just enough specifications, just enough and just in time documentation, etc, etc.
Definately. Agile is very flexible in terms of how many people are involved. Some methodologies, like Scrum, focus mostly on doing as much as possible in a limited time, like two weeks (sprints). That includes whatever you want it to. If your team requires QA, then that is part of it. As a loner, you decide what you want to include.
After the scrum sprint, you look at what you could have done differently to get more done, and move to the next one.
Some other methodologies focus more on getting features done in each iteration, say three small features developed, tested and refactored.
As you can see, there are tons of ways to apply agile to any project. You decide which aspects you want. Though obviously one integral part is doing things in small increments.
Yes
XP/TDD scales from one to one thousand. Pair programming is optional.
YES.
Agile is more of a state of mind than just a methodology of software development like waterfall.
Scrum is one of the very popular agile methodologies. You can study below aspects of scrum in detail:
Benefits of Scrum/Agile over Waterfall
How can you create better "products" with Scrum/Agile
What are the types of projects better suited for Scrum
Pros and Cons of Scrum
Scrum Rituals and why are they necessary (What advantage do they
bring)
Different roles in scrums and their responsibilities (Scrum Master,
Product Owner and Development Team)
After you have good understanding of working of scrum and its benefits, try to create a pet project.
You will have to play all the roles yourself. You can try to distinguish between what role you are playing currently by wearing different colored hats for each role.
Example:
Product owner : Think from product perspective, what should be the features in the product and why would they be important for your users etc. Then proceed with all the scrum practices.
Scrum Master: Keep checking if you are following all scrum rituals in the right sense and spirit and are you able to derive benefits out of it.
There will be limitations,example you cannot have Daily stand-up meeting, obviously because you are the only person in the project. But if you follow above, you should be good to secure a job and play your part well in the team.
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Developers can learn a lot from other industries. As a thought exercise, is it possible to build a passenger aircraft using agile techniques?
Forgetting cost for now; how feasible is it to use iterative and incremental development for both the hardware (fuselage, wings, etc) as well as software, and still come out with a working and safe product which meets the customer’s requirements at the time of delivery?
Does it make sense to refactor a plane?
Agile in software and Agile in manufacturing are really quite different, although they share similar principals and values.
Agile in manufacturing emerged in Japan in the 1950s. Read up on W.E. Deming and the Toyota Production System to find out more. It's all about constantly improving the process whereby a product is reproduced.
Agile in software evolved in the early 1990s as a rapid development model. It's all about constantly improving the product.
You can certainly build a plane using Agile manufacturing methods, I've no doubt that some already are. Anything built in Japan definitely will be as Agile manufacturing is very well established there (it's taught in primary schools).
You couldn't build a plane using Agile software methods because you can't afford to rapidly change the product - in software changes and mistakes are cheap and reproduction is free. This isn't the case for aviation.
You could design a prototype plane using something like Agile software methods - but it would have to be standardised in order to be reproduced (a design task in itself).
How would you work using Test Driven Development? Would you automatically build and test a plane every iteration? Would you be able to make a ten minutes build? How easy is to make changes to the airplane? Even if you are really flexible in your desing the building some components need to be sent to special factories so there is not inmmediate feedback.
From de design using CAD software you need to make a mould, take the piece of fiber, put it in the plane. Etc. So here a trivial change has a non trivial cost. In Agile you can make a very little change and have it tested, built and an ready to ship in 20 minutes. If small changes are expensive then the short development cycle and refactoring won't be so usefull. Your feedback can take longer than a week so there is a strong reason for thinking in advance like in the waterfall model. And every attempt has a cost in physical materials unless you are programming. The Idea is not new. Carpenters measure twice. Programmers just first code and then test.
In summary. There may be some similarities but it will definitively be the same.
I'm going to say "kind of". In fact there's one example right now that I think is pretty close to answering this question.
Boeing is attempting to do this now with the new 787 - see following: Boeing 787 - Specification vs. Collaboration (From the 777 to the 787, the initial specifications document supposedly went from 2500 pages to 20 pages with the change in technique.) Suppliers from around the world are working independently to develop the components for this aircraft. (We'll call this the "teams".)
So, I want to say yes, but at the same time, iterations in creating the aircraft has resulted in delays of 2+ years and has resulted in stories like this one - (787 Delayed for 5th Time)
Will the airplane ever get built? Yes, of course it will. But when you look at the rubber hitting the road here, it seems like "integration test" is having one heck of a time.
Edit: At the same time, this shift in technique has resulted in building a new breed of aircraft built out of entirely new materials that will arguably be one of the most advanced in the world. This may be a direct result of the more Agile approach. Maybe that's actually the question - not a "can you?" but a "if Agile delays complex systems, does it provide a more innovative product in the payoff?"
Toyota pioneered Lean Production which Agile methodoligies followed on from. For the building of the hardware of the aircraft lean production would be the way to go and for the software an agile methodology would be the way to go.
Pick the right tools for the job.
A great book following how TPS was created and works
http://www.amazon.com/Machine-That-Changed-World-Production/dp/0060974176
http://en.wikipedia.org/wiki/Toyota_Production_System
I think in this case you are thinking too big. Agile is about breaking things down into more managable pieces and then working against that. The whole idea of Agile (XP in particular) is that you do your testing first so that you cut the number of bugs out and because plane software needs to have a very high code coverage for its testing it fits in quite neatly I think.
You aren't going to 'refactor' the mechanics of the plane but you will tweak them if they are unsafe and thats the whole iterative approach for you.
I have heard of Air Traffic Control software written with Agile Methodologies pushing it forward.
This is taken from http://requirements.seilevel.com/blog/2008/06/incose-2008-can-you-build-airplane-with.html
***Actually, that’s not true,***
My first guess - this probably relates to some of the core differences between systems and software engineering. I am going to over simplify this and just say that it is about scale. Systems projects are just a superset of software and hardware projects, integrating and deploying some combination of these. The teams of people deploying systems projects are quite large. And many of the projects discussed here are for government or regulated systems where specification and traceability is necessary. I could see how subsets of systems projects could in fact be developed using agile (pure software components), but I’m not convinced that an entire end-to-end project can. To put this in context, imagine you are building an airplane - a very commonly referenced type of systems engineering projects. Can you see this working using agile?
All skeptism aside, I do think that iterative development most certainly could work well on systems projects, and most people here would not argue that. In fact, I would love it if we could find examples of agile working on systems projects, because the number one feeling I get at systems engineering conferences is a craving for lighter processes.
I decided to do a little research outside the conference walls, and low-and-behold, I found a great article on this exact topic – “Toward Agile Systems Engineering Processes” by Dr. Richard Turner of the Systems and Software Consortium. The article is very well laid out, and I highly recommend reading it. He defines what agile is and what he believes the issue why most systems engineering projects are not agile. For example, he suggests that executives and program managers tend to believe that the teams involved have perfect knowledge about systems we are building, so we can plan them out in advance and work to a perfect execution against a perfect schedule.
Agile Can Work With Complex Systems
He talks to how to the agile concepts can work in systems projects. Here are a few examples summarized from his article:
Learning based: The traditional V-model implies a one-time trip through, implying one time to re-learn. However, perhaps the model can be re-interpreted to allow multiple iterations through it to fulfill this.
Customer focus: Typically systems engineering processes do not support multiple interactions with the customer throughout the project (just up front to gather requirements). That said, he references a study indicating the known issues with that on systems projects. Therefore, perhaps processes should be adapted to allow for this, particularly allowing for them to help prioritize requirements throughout projects.
Short iterations: Iterations are largely unheard of because the V-model is a one-time pass through the development lifecycle. That said, iterations of prototyping through testing could be done in systems engineering in many cases. The issue is in delivering something complete at the end of each iteration. He suggests that this is not as important to the customer in large deployments as is reducing risk, validating requirements, etc. This is a great point to rememember the airplane example! Could we have even a working part of an airplane after 2 weeks? What about even the software to run a subsystem on the aircraft?
Team ownership: Systems engineering is very process driven, so this one is tricky. Dr. Turner puts the idea out that perhaps allowing the systems engineers to drive it instead of the process to drive them, while more uncomfortable for management, might produce more effective results.
There is this story of an aircraft engine plant (September 1999). Their methods seem quite agile:
http://www.fastcompany.com/magazine/28/ge.html
Yes, you could do it. If you followed Agile Software Development techniques too closely however, it would be astronomically expensive, because of the varying costs of activities.
Consider the relative costs of design and build. If we include coding as part of the software design process, then design is definitely the expensive part and build is ridiculously easy and cheap. Most Agile projects would plan to release every few iterations at least. So we can work in small iterations with a continuous build process. Not so easy when you have to assemble a plane once a fortnight. Worse if you actually plan on "releasing" it. You'd probably need to get the airworthiness & safety people on to an Agile process too.
I'd truly love to see it tried.
Yes, you can use agile techniques for building complex systems, but I don't know if I'd use it for this particular system.
The problem with aircraft is the issue of safety. This means every precaution needs to be taken, from correctly identifying and interpreting the requirements to verifying and validating each and every single line of code.
Additionally, formal methods should probably be used to make sure that the system is truly safe by making sure the programming logic is sound and satisfies its conditions properly.
I'm fairly certain the answer is irrelevant. Even if you could, you would not be allowed to. There are too many safety requirements. You would not even be allowed to develop the flight software using Agile. For instance, you do not have a Software Requirements Specification (SRS) in Agile. Yet, for any avionics software onboard an airplane that can affect flight safety you will need an SRS.
Of course one can refactor a plane.
When one refactor, one modifies the source code, not the binaries. With a plane it's exactly the same thing: one modifies the blueprints, not the plane itself.
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Maybe my understanding of agile development isn't as good as it should be, but I'm curious how an agile developer would potentially use off-the-shelf (OTS) software when the requirements and knowledge of what the final system should be are changing as rapidly as I understand them to (often after each iteration of development).
I see two situations that are of particular interest to me:
(1) An OTS system meets the initial set of requirements with little to no modification, other than potential integration into an existing system. However, within a few iterations of development, this system no longer meets the needs without rewriting the core code. The developers must choose to either spend additional time learning the core code behind this OTS software or throw it away and build from scratch. Either would have a drastic impact on development time and project cost.
(2) The initial needs are not like any existing OTS system available, however, in the end when the customer accepts the product, it ends up being much like existing solutions due to requirement additions and subtractions. If the developers had more requirements and spent more time working on them up front, this solution could have been used instead of building again. The project was delivered, but later and at a higher cost than necessary.
As a software engineer, part of my responsibilities (as I have been taught), are to deliver high-quality software to the customer on time at the lowest possible cost (among other things). Agile development allows for high-quality software, but in some cases, it might not be apparent that there are better alternatives until it is too late and too much money has been spent.
My questions are:
How does off-the-shelf software fit in with agile development?
How do the agile manager and agile developer deal with these cases?
What do the agile paradigms say about these cases?
Scenario1:
This can occur regardless off the OTS nature of the component. Agile does not mean near-sighted.. you'd need to know the big chunks.. the framework bits and spend thinking time on it beforehand. That said, you can only build to what you know .. Delay only till the last responsible moment.Then you need to pick one of the alternatives and start on it. (I'd Avoid third party application unless the cost of developing it in-house is infeasible.. but that's just me). Prototype multiple solutions to check feasibility with list of known requirements. Keep things loosely coupled (replacable), easy to change and full tested. If you reach the fork of keep hacking or rewrite, you'd need to think of which has better value for the business and pick that option. It's comes down 'Now that we're here, what's the best we can do now?'
Scenario2:
This can happen although the chances are slim compared to the team spending 2-3 months trying to get the requirements 'finalized' only to find that the market needs or customer minds have changed and 'Now we want it this way'. Once again, its a question of what is the point of time till which you are prepared to investigate and explore before committing on a path of action. Decide wisely with whatever information you have upto that point.. Hindsight is always 20-20 but the customers wont wait forever. You can't wait till the point of time where the requirements coalesce to fit a known OTS component :)
Agile says Do whatever makes sense and strip out the non-value-adding activities :) Agile is no magic bullet. just my 2 agile cents :)
Not a strict answer per se, but I think that using off the shelf software as a component in a software solution can be very beneficial if:
It's data is open, e.g. an open database or a web service to interact with it
The off the shelf system can customised easily using a similar programming paradigm to the rest of your solution
It can be seamlessly adapted to the rest of your work-flow
I'm a big fan of not re-inventing the wheel, and using your development skills to design the 'glue' between off-the-shelf solutions can be a big win.
Remember 'open' is the important part, and a vendor will often tout their solution as open when it isn't really.
I think I read somewhere that if during an iteration you discover that you have more than 20% more work that you initially thought then you should abandon the sprint and start planning a new one taking into account the additional work.
So this would mean replanning with the business to see if they still want to go ahead with the original requirements now that you know more.
At our company we also make use of prototyping before the sprint to try and identify these kind of situations before they arise on a sprint. Although of course that still may not identify the kind of situation that you describe.
C2 wiki discussion: http://c2.com/cgi/wiki?BuyDontBuild