OS/2 codes: How to emulate COPY-ON-WRITE #0 Prologue
Copy-On-Write is a feature to improve copy performance. That is, memory blocks share the same contents until copy operation to those blocks really occur.
By postponing copy-operations until it is needed really, it's possible to remove initial overheads of copy operation.
This was needed to implement mmap(). Espeically, MAP_PRIVATE. On Linux(http://man7.org/linux/man-pages/man2/mmap.2.html), copy-on-write feature is used. I thought it's not possible without kernel supports. However, Dave Yeo suggested DosAliasMem(). I thought it may be possible. I did implement such a feature.
A series of the following articles are records of implementing copy-on-write on OS/2.
By postponing copy-operations until it is needed really, it's possible to remove initial overheads of copy operation.
This was needed to implement mmap(). Espeically, MAP_PRIVATE. On Linux(http://man7.org/linux/man-pages/man2/mmap.2.html), copy-on-write feature is used. I thought it's not possible without kernel supports. However, Dave Yeo suggested DosAliasMem(). I thought it may be possible. I did implement such a feature.
A series of the following articles are records of implementing copy-on-write on OS/2.
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