blackbox

[caption id="attachment_751" align="alignright" width="241" caption="Something happens in there... with gnomes I think."][/caption]

The Blackbox, cornerstone of computer science, thing of mystery and beauty. It is the fundamental concept that allows us to build bigger and better abstractions, making life easier for everyone. A blackbox is something that has well defined inputs and outputs but the manner in which it functions in unknown. The classic example of this is a library function, sqrt(9) takes the number 9 and returns the square root 3. There is a well defined input (in this case 9) and a well defined output (the square root, 3). How does the function produce this result, who cares?

As programmers we can focus on what we are good at, if someone loves programming math algorithms they can make a kickass math library, if they love web programming, here comes Rails. Then when I'm interested in writing a web app that needs to do some math, I don't have to worry about how to find the square root of some number, there is a handy blackbox all ready to go. This is a huge boon to productivity, I'm happy, math programmer man is happy, and the user is happy because they don't have to use my buggy homegrown math libs that say they owe a $47 tip on a $9 check. (And my math degree weeps at me)

This is all well and good, the problem comes when you need to know what's going on in a blackbox. There are any number of scenarios in which you may need to shine light into the depths of a blackbox. You have some strict performance or memory requirements, the blackbox's "well-defined" outputs are failing (what do you do when you call out to sqrt(9) and get 7.2 back) or the use of a blackbox is having some negative side-effect. In these situations the whole damn thing comes crumbling back down to earth, you now need to roll up your sleeves and get it done. Here is how you should approach the problem.

• RTFM (Read the Fucking Manual) - This is the first step, if a blackbox is eating up too much memory see if there is a way to force a limit, if it is throwing an exception, check why that could be the case. Basically before you do anything else you should try to make sure that the blackbox is actually broken, because chances are that any sufficiently popular blackbox is going to have much more real-world use and rigorous testing than your new client code. This boils down to, don't blame the compiler for your shitty code.


• Ask someone familiar with the blackbox - After you've actually RTFM you can move on to this stage, seek help from someone more familiar. If there are colleagues that have used this particular blackbox ask them first, they may have already gone through this entire list and can shortcut you to the answer. If you have no colleagues to turn to, try turning to the community or the creator, if that fails try throwing it up on a more generic community like, stack overflow.


• Go to the source - If you are working with an open source blackbox then it isn't really a blackbox, just go read the code and see what it's doing. This is much easier said than done, so make sure you have exhausted the first two steps before diving into this one. If you are using a closed source blackbox you can either attempt to get the source through some sort of development channel (although this is unlikely) or you can decompile and look at that. Tools like RedGate's Reflector or the Java Decompiler Project can help to get at that closed source.


• Workaround - Sometimes no matter how dogged your determination, you can't seem to figure out why the blackbox isn't working right, at this point you have exhausted the detective route, time to pull a MacGyver. If you can figure out someway to use the blackbox and workaround the deficiency then go ahead and do that. The important thing is to take this workaround and record it properly. Create an adapter, thin wrapper, or function. Make your own lightweight blackbox that is 1 part the old blackbox and 1 part workaround aggregated together.


• Roll your own - Sometimes you get seriously desperate, you have researched your fingers to the bone and tried to work around the problem. You are at the end of your rope, the deadline is looming and the only thing standing between you and your project compiling is some pos third party closed source blackbox. Sure it would be nice to have a sqrt function nicely wrapped up for you, but hell you can dust off that part of your brain that remembers what a square root is and write your own function to find it. The important thing is that this should be the very last thing you do, after all other options are exhausted. Many a programmer will do this first or second, and that is Seriously Fucking Wrong©.

The power of a working blackbox is only matched by the frustration of a wonky blackbox. The good news is that a lot of blackboxes work really well sitting there quietly trimming our strings and rooting our squares. There is that every once and a while though when despite our best efforts we have to dive headlong into a blackbox and shine some light around.