2008.11.14 23:31 "Re: [Tiff] Memory leak (TIFFOpen, TIFFReadTile)?", by Bob Friesenhahn
I use "rCm" for TIFF files above a certain (rather artbitrary) size -- 80MB in my case -- for the same reason, but as long as memory is plentiful, memory mapped files are somewhat faster. I also used to use 'rm' for smaller files on some Windows operating system (ME I think) because memory mapped files were left locked.
Memory mapped files are much faster provided that the system has adequate RAM to cache the whole file, and the file is read repeatedly. Computer RAM has become quite cheap so computers are commonly comming with multiple gigabytes of RAM. This changes the equation.
For my application, libtiff uses my application's I/O routines, which decide if memory mapping should be allowed based on user settings and the amount of physical memory.
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/