Systems ≈ Random?

I don’t quite believe that yet, but I’m getting closer.

Blogger has a ‘known problem’ at the moment which makes it difficult to insert a picture in your post.  I won’t go into details, because they’re boring and nerdy (and they’ve identified a way round it,  which seems to work, whilst they fix it) – the thing is that it only happens if you use a particular browser.   That’s like saying that an identical can of beans will have different contents depending on how you carry it home from the supermarket.

The point that worried me was the one jokily expressed in this post’s title: that the behaviour of some computer systems increasingly seems to approximate to randomness.  Like I said, I still just about refuse to believe this, even though Blogger regularly shakes my faith.

Anyway, in support of my probably misplaced optimism, I offer you the following true story.

Not that many decades ago, I was involved in developing and testing a new computer application, which duly went live.  It worked fine for weeks, until suddenly a particular transaction caused it to crash catastrophically, dragging several other things down in its wake. 

We pored over the content of the guilty item and could see absolutely nothing unusual about it, and so handed it over to the lead programmer, Anjam.  Two hours later, he came back with the answer.

“This only happens,” he explained, “when the length in bytes of the resulting record is an exact multiple of 256, plus one.”

Over his shoulder, as he walked away, he grinned.  “Sloppy testing.”