Survey of PackBits-like RLE compression schemes

This post is a survey of some run-length encoding (RLE) data compression formats, most of which are used for bitmapped graphics. One such format is PackBits. It's sort of the granddaddy of them, or the canonical example of such a format. Sometimes, formats similar to it are said to be "PackBits-like", though the term doesn't …

Daylight Saving Time

Public opinion seems to be turning against Daylight Saving Time (DST), despite the fact that most of our clocks now change automatically, and despite the fact that most people don't even seem to have a clear understanding of what DST does, and what its purpose is. I'm not necessarily the biggest proponent of DST, but …

Analyzing some Windows Write files

Write is the word processing program that came with Microsoft Windows 3.x (and earlier versions of Windows, but it's 3.x that I'm concerned with here). Many thousands of free and shareware programs were written for Windows 3.x, and a lot of them include some documentation in Write's WRI file format. Objectively, most of them should …

The 2019 TLS certificate serial number mess

Remember the Great TLS Certificate Serial Number Brouhaha of March, 2019? Millions of website certificates have been mis-issued! Everything is insecure! The sky is falling! Revoke and replace, ASAP! I barely do, but I remember thinking it was a really stupid overreaction. Now I've gone back and reviewed what happened, and I'll try to explain …

Does 0.999… equal 1?

Does "0.99999999…", with the 9s continuing indefinitely, equal 1? Well, of course it does. This is not a new question. The internet was invented on a Tuesday, and by Wednesday afternoon half of its denizens were trying to explain to the other half why 0.999… does, in fact, exactly equal 1. The explanation, we're told, …

Are humans descended from monkeys?

Are humans descended from monkeys? It's an interesting question. Too many well-meaning scientifically-minded individuals are quick to reply with a defensive "No! We just have a common ancestor!" But that's not a very good answer. It ignores the fact that the question is ambiguous, and that the definition of "monkey" is ambiguous. Sometimes the answer …

Computerized chessboard displays should be better

You can't tell everything just by looking at a game position on a traditional physical chessboard. If you see: You can't necessarily tell: the board orientationwhose turn it is to movewhat castling rights existwhich pawn, if any, can be captured en passant There are also lots of other things you can't tell, such as whether …