karl@ficc.uu.net (karl lehenbauer #) (12/03/88)
In article <554@auspex.UUCP>, guy@auspex.UUCP (Guy Harris) writes: > >System V extensions could be added to Mach. > > Including the S5R4 "mmap" system call, complete with the ability to > create a shared writable mapping to a file, right? Not sure. I don't have S5R4 manuals yet. Looking at "Architecture-Independent Virtual Memory Management for Parallel and Distributed Environments: The Mach Approach" is a bit confusing because it says "In Mach, file mapping is used for reading data only," (pg. 55) yet examples for mapping a file for writing are given on page 57. If BSD 4.3 has this capability, Mach does, because Mach is binary compatible with 4.3. Finally, even if this support isn't provided, it appears to me on the basis of a cursory examination that shared writable file mapping could be implemented via a "user-provided" backing store object and pager. Mapped files themselves are implemented through such a mechanism. -- -- uunet!ficc!karl