The context of programming

Recent events in my place of work have lead me to ponder the concept of programming context once again. I suspect it is a pervasive concept as I seem to come across it on a regular basis in quite different circumstances. Let me explain.

If I am asked to write a program that accepts two numbers and returns a third number, being the product of the two, then there is not a lot more I need to know. Perhaps knowing the possible range of input numbers would be useful, but really this is a pure mathematical problem and has no context.

If I am asked to write a program that accepts two numbers and returns a third number - the number of residential addresses in a database that fall between those two numbers - then there is quite a bit more I need to know. I need to know whether just street numbers alone should be checked, or whether street names should be included (5th Avenue, for example). Even within street numbers alone, what about flat numbers? It's a bit more complex than the first example as there is a context. I.e. what are we actually trying to achieve here?

Now in a third example, I am asked to write a program that accepts two numbers (x and y) and returns a third number which is the number of active users who have been logged in between x hours and y hours. Again, now the context is complex. How do I define a "logged in user"? Do I define one interactive session as one user, or do I need to reduce this to unique users because some may be logged in more than once. What about "special" users such as system supplied IDs? Should they all be counted, none, or only some?

But the third example is even more complex than I have shown so far. Consider that this function needs to work in a function test environment, in an integrated test environment, and in production. There are some processes that occur only in production, some only in test and some on both. Will this affect the outcome? Is testing on the test system going to be good enough to know it works in production?

Hang on a minute - aren't we talking about system programming? Well, maybe yes and maybe no. If this program is needed to manage software licensing, then it's a system program. But, if it is needed to manage the number of customer service representatives assigned to different parts of the call centre, then no it is not system programming. If it is being used to achieve load balancing for application service jobs then it could go one way or the other.

Now that was a somewhat contrived example, but it helps me to illustrate my point. In all three cases, take two numbers and return a third. The first example I would expect absolutely any programmer to be able to achieve. The second example I would expect any programmer to be able to achieve if complete requirements are provided. If the problem is only defined as I described, then you would need an analyst programmer. For the third example, who would you give the job to, generically speaking?

This is where I see a massive gap. I, myself, have been fortunate to have been involved in both application and systems programming fairly extensively and even if I say so myself I think I'm pretty good at covering off the sorts of issues described above. It also means I am frequently seeing other programmers who are failing to account for the "system" level factors.

In a specific recent case, a developer insisted that my team (who are a development & test support team) replace one version of a program with another so that it 'behaved like production'. That should have been the first red flag. (I was not involved at this stage so I don't know whether I would have caught this at the start.) Why was the test system behaving differently to production?

Well, the developer got his wish and proceeded to begin to make his related code work. Meanwhile, large numbers of other people were tripping over the problems introduced. After several days of analysing the problems we concluded we had to put things back the way they were. To quote Spock - "The needs of the many far outweigh the needs of the few." This programmer was looking in far too narrow a context in defining what needed to be done. He had no concept of the roles this particular program was playing, nor the large number of dependencies it had. For instance, an automated regression testing suite completely failed because of the change.

But perhaps the most spectacular case of lack of context that I have ever encountered was in a previous role.

The product in question was enterprise software being used all around the world and it was incredibly complex. Customers had requested the ability to use off-the-shelf reporting tools (such as Crystal Reports) to create their own reports. The development organisation realised this meant less work on such things for us and considered this was a good idea - but dangerous. Great they can write their own reports, but how to let them into a massive, complex database without (a) massive confusion and (b) the opportunity to corrupt it.

So a plan was hatched to deliver a new library (for self containment) of logical files (views) which would collate the data into meaningful constructs and, importantly, be read-only. My team (again in development & test support) figured out how to deal with this new library for the purposes of the testing done on it. For the most part we just manually created and destroyed these libraries as required and used some of our own toolset which, importantly, is not delivered to customers.

At some point I got to thinking...How are we going to deliver this? The initial response I got from the designer was "on a tape/CD with the rest of it." To cut a long story short, I soon proved that it is impossible to ship a library full of logical files. Period. Can't be done. I took this information back to the designer, along with a rough sketch design of a simple tool which could alleviate the problem, and also be useful within the development shop.

The response? "We didn't budget for that." * Sigh *.

In the end, I wrote a quick (hack) version of that tool on the day we packaged the software. Some months later someone contacted me saying that there was a bug in my code. I sent them to the designer to have it sorted out.

Thanks for reading.
Allister.