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[REBOL] Re: Looking over the horizon - Rebol 3

From: greggirwin:mindspring at: 12-Nov-2003 11:17

Hi Petr, PK> Maybe off-topic - but some time ago there was mention of so called PK> memory-mapped files. What is that? Under Windows (not sure about other OSs) an MMF (Memory Mapped File) is a "view" of a disk file mapped into memory. Multiple processes can share mappings and so share data in memory--i.e. one can write to the MMF and others will see the changes instantly. They can also be used to let you write code that operates on disk files without having to deal with all the niggling I/O details in a case where the file is too large for memory or something. One of the classic examples, IIRC, was to use strrev on a MMF to reverse the data on disk, no matter how large the disk file was. Very handy for sharing data between processes. I think most, if not all, data sharing APIs map to them under the hood. -- Gregg