memory-mapped-files – Make Me Engineer

Inno Setup Get progress from .NET Framework 4.5 (or higher) installer to update progress bar position

June 4, 2023 by Tarik

The following shows Pascal Script implementation of the code from How to: Get Progress from the .NET Framework 4.5 Installer [Files] Source: “NDP462-KB3151800-x86-x64-AllOS-ENU.exe”; Flags: dontcopy [Code] // Change to unique names const SectionName=”MyProgSetup”; EventName=”MyProgSetupEvent”; const INFINITE = 65535; WAIT_OBJECT_0 = 0; WAIT_TIMEOUT = $00000102; FILE_MAP_WRITE = $0002; E_PENDING = $8000000A; S_OK = 0; MMIO_V45 = … Read more

How does mmap improve file reading speed?

April 17, 2023 by Tarik

mmap works differently. It is anticipatory and adapts to the program’s access pattern. Also, specific policies can be set via madvise to further fine tune usage. For a much more thorough discussion of how mmap works in a demand paging environment, see my answer here: Which segments are affected by a copy-on-write? as it also … Read more

How big can a memory-mapped file be?

December 2, 2022 by Tarik

You’re being too conservative: A memory-mapped file can be larger than the address space. The view of the memory-mapped file is limited by OS memory constraints, but that’s only the part of the file you’re looking at at one time. (And I guess technically you could map multiple views of discontinuous parts of the file … Read more

How to unmap a file from memory mapped using FileChannel in java?

July 7, 2022 by Tarik

Following static method could be used: public static void unmap(MappedByteBuffer buffer) { sun.misc.Cleaner cleaner = ((DirectBuffer) buffer).cleaner(); cleaner.clean(); } But this is unsafe solution because of following: 1) Lead to failures if someone use MappedByteBuffer after unmap 2) It relies on MappedByteBuffer implementation details