Big Ball Of Mud Development Model

Lightborn writes: "The Big Ball of Mud Development Model examines exactly why so many projects (software and otherwise) end up looking like a bowl of spaghetti. A good list of things not to do when developing a project."

Comments

Reading code ...

[Anonymous Coward]

Open source is massively contributing to better source, if it were only because more students now not only get the opportunity to read real-life code.

Even stronger, learning to read code has become more important than churning out vast amounts by yourself.

Inadvertedly, open source addresses a serious flaw in computer science education: the fact that students should, in the first place, learn to read, use, alter and inspire themselves from existing bodies of code, instead of churning out unrealisticly small mickey mouse examples.

Well-written code reads like poetry.

Re:The Achilles' Heel of OSS

[magic]

Yes. The problem with OSS is that much of it is evolved code, not designed code. This leads to robust and secure systems, but not ones where it is easy to add features or hunt down new bugs. Consider the example of an AI neural net (or the real thing, if you like squishy things). You've trained the thing to give mostly right answers by propagating feedback through the net in complicated ways, but have sacrificed any possibility of understanding why it gives the right answers. It is like a roof made from patches with no actual roof left. It keeps the rain out, but has lost all structure and is harder and harder to deal with. (Too many analogies in that paragraph).

I've finally adopted a very game-programmer oriented philosophy towards development. Code should be written so that it is the specification, with appropriate inline comments documenting it and really clear variable names. Programmers should be extremely vigilant, and continuously roam their own code making sure that it actually reflects the current state of assumptions about the system. Whenever a change is made to the system, anything remotely affected should be proactively rewritten to reflect the change. This is pretty much how Abrash describes himself and Carmack working on Doom and Quake, and it is really successful. You keep performance up, stay in touch with your code, and never accumulate cruft. Bugs are immediately ferreted out and the programmer must never fear diving into code to tackle a big cleanup job, and can never allow pieces of code to exist that she (or he) doesn't understand.

Of course, you need massive automated tests to make sure your rewrites don't screw anything up. Designs must be extremely abstraction oriented, with a close eye to strong interfaces and bootstrapping, otherwise you will end up with so much code that it is impossible to manage the continual cleaning. And you need really dedicated programmers.

When I look at the Doom and Quake source, and the code that my own dev. team has produced, I see that the results are worthwhile. Each routine is beautifully crafted and works flawlessly. The codebase is a fraction of the size you would expect because so much effort has been put into doing everything the right way and eliminating broken or excessive code. And no bugs...

magic

It took me a while to figure this out...

[Anonymous Coward]

For a long time I couldn't figure out why others had such a hard time fixing bugs and changing their programs, while I could do it without any problems (no I'm not trying to be arrogant or pretentious).

Then a coworker made this remark: "Ray how can you write such well-organized code in one pass?" At first I couldn't understand what she was talking about, after all doesn't everybody constantly review their code? Doesn't everybody constantly rearrange functions and classes, rename variables, redefine protocols? Apparently not.

Correct me if I'm wrong, but it looks to me like most programmers write something once then spend the rest of the time trying to get that working. They never go back and rewrite the code, they just keep adding fixes to it. How can this ever work smoothly?

I've also seen and heard a lot about processes to make a program, or anything else, come out right the first time. I don't get that either! To me, the only objective when writing programs is to make it easy to change. Period. If it's easy change, it's easy to fix bugs, it's easy to enhance, and it's easy to rearrange and redesign with hindsight.

If you want to have a good time programming, do yourself a favour: learn the tools to make global changes to your code quickly, then spend a _lot_ of effort rearranging your code and renaming things as your program evolves.

Re:It took me a while to figure this out...

[jetpack]

While I agree with everything you said, a reply to your post's title is probably worth a comment.

It took you a long time to figure out. You were probably doing it instinctively before figuring out whatever everyone else's problem with maintenance was. Fair enough. I, on the other hand, learned proper maintenance through a gradual progression, and during that journey learned to recognize the shortcomings (and strong points) on others when it came to maintenance and design.

However, I think the significance of this paper is that it actually addresses some solutions to problems rather than just explaining the problems, and thereby, hopefully, promoting and explaining useful maintenance and design techniques.

This article is one of the few times that I've seen this. For example, I've read "Anti-Paterns", which is sited in the article, and quite frankly, I was rather less than impressed. It points out problems, but it's only suggestion, usually, is "rewrite". Not much of a help to the newcomer to programming. On the other hand, anyone that has been coding for any length of time, will find the symptoms that this book points out, and (obvious) solutions, as a waste of reading time.

The posted article, however, I thot made some useful points through analogy that I think might actually help some newcomers to programming understand some of the issues. I particularly was impressed by the section on "shearing". The project I'm currently working on deals with this issue particularly well, and I've used the concept since (unfortunately, I didnt design the system, and therefore cant take credit for it's chameleon-like design). This article relates the issue of shearing quite well.

So, in summary, [0] you are right, [1] this article is important because it actually shows *why* you are right.

Now, if I can just get management to read this and agree. (yeah, right)

Cheers.

Re:The Achilles' Heal of OSS

[Kaufmann]

I agree with you in part, but pigeonholing all of OO as obscurantist and overcomplicated is as erroneous as overhyping it as if it were the Second Coming. There is nothing wrong with the motivation behind OO itself; the problem lies mainly in implementation. Specifically, what we now consider to be "OO programming languages" and "OO design practices" goes far beyond the original concept of both, and much of it is indeed obscurantist nonsense, which induces a huge amount of needless overhead, both of the conceptual kind on the designer and of the practical kind on the implementer. This is especially true in the case of small to medium software projects, even more so because often designer and implementer are one and the same.

Case study 1: C++. An extensive critique of C++ as an OO language for production systems, from the point of view of an Eiffel-cheerer, can be found here; in my opinion, it suffices to say that, given its status as just one step up from a C add-on, and given that, when building on such a shoddy conceptual infrastructure as C's, it's hard to conceive how one could do any better, C++ should be considered to be outside the scope of this discussion.

Case study 2: Java. Now, Java is built from head to toe for maximum OO. This is incredibly intrusive to anyone who wants to do some real work using it, as opposed to just drawing nice schemes and writing UML models. Java is built to enforce those styles and concepts of programming which the designer felt to be correct. It's languages like this which give OO a bad name, and they should be shunned.

Case study 3: Perl. Perl was built to be a scripting language - in Osterhout's original conception, a "glue" language. Thus, practicality being the most important goal in it, it's easy to understand why Perl's OO is as it is. Specifically, it doesn't exist per se; no special syntax or semantics is enforced for OO programming, in fact all of it is built upon simpler, pre-existing constructs - specifically, taking advantage of an isomorphy between modules and classes, objects and references (via abuse of the bless() and ref() functions), methods and namespace-local subs. This makes a transition to OO practices easier as a project grows. It also allows one to implement the concept of an object as he sees fit - usually the slot approach is used, using hashrefs, but there other approaches for specialised cases - including objects as indices into class-wide property arrays, an approach described in "Advanced Programming with Perl" and which is useful for when you need many objects and creating a hash table for each would be a waste of space. The discussion of OO in Perl could be extended further, but it suffices to say that, in true Perl form, it restrains from imposing a paradigm on the programmer, trusting instead that he knows better.

Case study 4: Smalltalk. Smalltalk is widely considered to be the godfather of modern OO (yes, Modula had something called "OO" before Smalltalk, but a quick glance at both languages will make it clear right away that most of what we call OO today was fathered by Smalltalk); this, combined with the widespread availability of "OO software design tools" for the environment, could lead to some people blaming it unfairly for their current issues with the paradigm. In reality, when using Squeak, a computing environment integrated with a derivative of Smalltalk, I've found the use of OO in programming the system to be perfectly natural, in contrast to the uncomfortable feeling that you get from using, e.g., Java. Part of this comes from language design itself, which makes the concept ubiquitous in a very straightforward and graspable way, but most of it comes from the environment, which is fully built on objects. In the Morphic system, you can "see" and "touch" - inspect, manipulate, delete - all objects alike. The user- and programmer-levels are intertwined, and so instead of programs, methods are the elementary user-level executable unit; this removes one unnecessary level of encapsulation, leaving all objects free to talk to each other, without being first streamlined into the procedural mold enforced by the "program" concept. All of this, plus the elegance of the Smalltalk language, makes for a system which is very easy to program, and which leaves relatively little to be desired. Thus, I consider Squeak to be a paradigm of well-used OO.

Hell, I think I've said more than I set out to... I hope at least some of it is of any use.

The Achilles' Heal of OSS

[Reality Master 101]

I'm really glad to see this. In my experience, the great flaw in the OSS model is the quality of the code. Can we be honest? The vast majority of it is complete crap, developed by amateurs with absolutely no clue how develop to professional standards.

The OSS community needs to establish some quality standards. Linux code is relatively new, but this is going to bite everyone in the butt as the code gets modified more and more, and software rot starts to rear its ugly head.

Unfortunately, the vast majority of OSS developers are not very old (less than 25), and don't have the perspective to appreciate trying to maintain 10 year old code that has been modified 20 zillion times.

Mark my words: Unless coding standards get real important soon, OSS is going to collapse under its own weight. "As long as it works" is not good enough.

--

Re:The Achilles' Heal of OSS

[retep]

The vast majority *is* crap. But the stuff that is important, libc, the Linux kernel, GCC etc. isn't. If you look at Windows there is lots of third party software that is complete junk. The case is the same with Linux. But the "big stuff" is all big *because* it's good, well designed software. OpenSource can produce crap, anyone armed with a compiler (standard on most UNIX's) can produce utter junk. But will that junk be used? Will anyone even know it exists? Of course not.

Both OpenSource and Closed Source development can produce junk software. And both can produce great software.

Some Good Software

[retep]

One example of some very well designed software is the Shuttle OS that powers NASA's Space Shuttle. In 420k lines of code each revision has only had 1 bug each that wasn't caught by testing. If we *really* want to make some good software it wouldn't be a bad idea to take these lessons to heart. OpenSource software is already good, lets make it better. Full artical here.

slashdotted DOS attack, Google mirror

[crisco]

Here is the obligitory mirror courtesy of Google.

I thought the comparisons to Design Patterns were hilarious but way too true.

I code like I write

[geekpress]

I was writing philosophy long before I was coding (PERL mostly), so it doesn't come as much of a surprise to me that I code using the same method that I use to write.

When I write, I go along a line of argumentation until something starts feeling wrong, like I've strayed too far. That's when I go back, read all that I have written, fix it up, and then continue writing until I have to stop again.

When I code, I do exactly the same thing: code until it feels too messy, go back, rework, continue to code anew, get stuck, etc.

The result has been fairly decent code that isn't too bad to alter over time. However, sometimes I get tempted to overhaul code when it really isn't necessary, because some minor issues are bothering me. (This happened with GeekPress when I was just a few days of programming away from launch, but thankfully my husband helped me get over my fussiness!)

Since I've always completely coded my own projects (even when working within a company), I have no idea whether others code in a similar fashion or not. (I'm sure that my situation is greatly simplified by the fact that I don't have co-programmers. That seems like a nightmare to me!)

-- Diana Hsieh

Really Good Software Architects

[roman_mir]

It is hard to find really good Software Architects. Lately the tendency has being to produce code at the speed of rabbit procreation - 10 times a week. The problem has gotten worse over time due to the popular rapid development tools such as Visual Basic for Windows and Object Oriented approaches such as Java for JVM. The bad news is that this deters new good programmers to appear instead of old ones. The old programming school did not have to face such issues as handling millions of users and huge databases or creating user interfaces accessible to a novice user, they were mostly concerned with the speed. Ability to hack together some brilliant Assembly code was the primary concern, I admit it is cool.

Today most so-called Microsoft Certified 'Engineers' have no clue what 'Assembly' stands for but they still don't know how to handle millions of users terrabytes of data or create decent user interfaces. The problem is that computer science became popular among those people who have no real call in their lives and who regard their work as simply a way of getting their salary. Large salaries of IT department does not help too much, they create an unhealthy attitude towards the profession.

Working on a large project that is supposed to be scalable to millions of customers, supposed to handle multiple user interfaces of various wireless devices (PDAs, Cell Phones etc) over time I had to design various components of the system. In the beginning there was only an idea which later became basically a large collection of various components. I have never before had to design and build such a complex piece of software and I am just happy that my current formal education allows me to make sound judgements about network traffic averages and variances, the speed of code in terms of iterations (big-O, big-Omega, big-Theta, they are usefull after all), being able to handle various datastructures and even creating my own new tree designs.

Nevertheless, all the way through I've felt the need for an experienced software architect. My company did not have one and we still don't and I think it is very difficult to find one with really good experience and skills.

Once I have seing a real software architect at work (he was in his forties) he was giving a presentation of his design and it was jus WOW. I mean even after working professionally for three years and handling hundreds of different programming and design problems, I don't think I could produced such a thoughtfull design that goes into details and goes over every possible issue with all the computations and considerations. It was beautiful.
I wish we all could learn from the best.