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It seems Ken Thompson, one of the people who wrote Unix, was asked what he thought of the date-rollover problem in Unix (In the year 2038, the Unix date value wraps around to 0). His reply was that he didn't care as he was going to be dead by then. A speaker at the UniForum NZ 97 conference at Rotorua quoted this anecdote. When I mentioned this to a friend, he said that this speaks a great deal for Unix since the questioner implicitly assumed that Unix was still going to be around in 2038. Well is it? Is it worthwhile learning Unix skills and still be employable in the decades to come?

1. Introduction

In spite of Faye's repeated insistence that Mike leave the toilet seat down, Mike made the unfortunate mistake of accidentally leaving it up one day, only to suffer its dire consequences. Faye threw such a fit that Mike had to sleep on the couch almost that whole week until he made it up to her.

In spite of Mary's repeated insistence that Peter bring her a bunch of red roses every day on his way home from work, Peter made the unfortunate mistake of forgetting to do so one day, only to suffer its dire consequences. Mary threw such a fit that Peter had to sleep on the couch almost that whole week, until he made it up to her.

In a certain village on the remote plains of Fornicalia there exist some men who are having affairs with the wives of other men. Now there is a gruesome custom in this village which requires a woman to kill her husband the morning after she discovers that he is having an affair with another woman. It also happens that every woman knows whether every other man is having an affair or not except her own husband.¹ So life in this village goes on peacefully since no woman can know for sure that her own husband is cheating on her. Unfortunately, an Oracle from the pure and untainted shores of distant Stobon visits the village one day and proclaims that at least one man in this village is having an affair. What happens after this?

Readers are urged to think of a solution themselves before proceeding further. We first present the solution and its proof and finally go on to discuss the information theoretic aspects of this remarkable problem.² A similar treatment of this and some other aspects of the puzzle can also be found in Moses et al. (1986) and Halpern and Moses (1990), both of which also cite other sources where further discussion of the topic can be found.

"The sex of your baby predicted CHEEP! Guaranteed Results. 150% REFUND for wrong predictions"

There you have it - a simple and sweet business plan if ever there was one. But people who ponder can promptly peer past its imposturous garb. This is just gambling in disguise. Suppose the service costs $1.00 and a thousand naive couples paid for it. On average, five hundred of them will receive a refund of $1.50; the rest will presumably be happy to have been told the sex of their baby. Despite the refunds, however, the service provider is $250 better off than she was before, and for no more effort than flipping a coin for each customer. Immediately, one can tell that the scheme is a rip-off, aimed at defrauding innocent parents-to-be of precious baby-dollars.

To the uninitiated, that is exactly how CPA advertising is being framed by ad-networks steeped in profiting from traditional methods: "Give us your ads. We'll show them. You only pay for ads that result in a sale, but not a cent on the rest." On the surface, yes; this does look like a scam. But fortunately, this is not what CPA is about. In fact, CPA represents the exact opposite. CPA ad-networks don't just flip a coin to show an ad. Considerable effort and investment go into determining where each ad is most likely to appeal, and, of course, web real-estate on which to show ads does not come free either. A CPA network will actually "lose" money if you don't make it and therefore it is in their best interest to make sure you are successful.

If you could see the individual molecules of air in a perfectly still room, you would see that the molecules are anything but still. They are moving in all directions, apparently randomly. Each has its own spin, and its own story to tell. Yet the room itself, made up of millions of these molecules, has the picture of perfect calmness as though nothing in it is even stirring. In the calm of this room lies buried the solution to the most pressing problem in objective journalism.

Today, Linux is a beautiful thing and I typically waste no opportunity to evangelize it to friends considering a new desktop purchase. I mean, if the average user today calculates how much of his or her computer time is spent either on-line or within office applications, it seems like common-sense to buy a Linux desktop with Firefox and Open Office rather than buy expensive Microsoft products. Homer Simpson captures the sentiment best in the opening line of the latest Bart Simpson flick. Why would someone pay hard-earned cash to get something we can get for free? We're all giant suckers!

Forget OLAP cubes and pivot tables! As is the case most of the time, 90% of the insight can be gleaned from very simple data plots. To be sure, the remaining 10% does shed valuable new light, but is also orders of magnitude relatively more tedious to distill.

One of my favorite tools for performing quick sanity checks on data and even for inferring high-level trends is a histogram; it simply partitions your data points into a fixed number of buckets, with each bucket holding points that fall within a given range. The resultant bucket sizes are then available to eye-ball, often plotted as bars whose lengths are proportional to the number of elements in the corresponding buckets.