It's prehistory week at the jorendorff household. This week I learned:
The fossilized skeletons of a 14-foot Xiphactinus (a mean-looking Late Cretaceous fish) and its last meal, a merely 6-foot bony fish which it swallowed whole, are on display at the Sternberg Museum of Natural History in Hays, Kansas.
Woolly mammoths had a three-inch-thick layer of fat underneath thick skin, fur, and long shaggy hair. (Yet their environment was such that occasionally one would be flash-frozen, without spoiling the meat, to be eaten by modern dogs ten thousand years later.)
The original Nintendo GameBoy had an 8-bit processor with a HALT instruction which games were supposed to use to wait for interrupts. At least one game would sometimes busy-wait instead (yuck!).
There's a tool, dwarfdump, that dumps DWARF debug info from an executable or object file.
On Mac there's a lazy debug-info-linking scheme that causes dwarfdump not to see any DWARF in compiled executables. The Mac tools that come with Xcode are aware of this magic, but dwarfdump isn't.
The Spiral of Theodorus shows that the square roots of integers can be constructed with straight edge and compass.
According to Tim Sweeney, quoted in this DDJ article:
Any loop written in a traditional programming language can be vectorized, to execute 16 iterations of the loop in parallel on Larrabee vector units, provided the loop body meets the following criteria:
- Its call graph is statically known.
- There are no data dependencies between iterations.
So compilers will be able to do a lot more vectorization.