Archive for May 12, 2010

Wednesday, May 12, 2010

How malloc Works on the Mac

Matt Gallagher:

The reason for separate regions for tiny and small allocations is that it allows the region’s metadata to be more efficiently tuned to tracking the size of object it contains. For “tiny” allocations, tracking memory down to 16 byte units is worthwhile (it allows freed space to be reclaimed better and doesn’t waste large amounts of memory around allocated objects). For “small” sized objects though, tracking at this resolution would be a poor tradeoff between CPU time (traversing through lists of freed or allocated blocks) and memory efficiency—the coarser 512 byte resolution is more efficient.

Canon S90 Review

Tim Bray:

There are really two choices: Put the ISO on the cool funky ring around the lens and the aperture compensation on the fiddly dial on the back; or the other way around. And the problem is that it’s hard to hold the camera without jostling that dial at the back.…So I’ve ended up parking the exposure compensation on the too-accessible back dial, because those adjustments are reflected in the CRT and you can tell when you’ve accidentally cranked it.

The camera’s great, but I accidentally hit the back dial, too. Setting it to exposure compensation seems to be the best way to minimize surprises.