memory-mapped files

[Kagamin]

Kagamin Wrote:

> May be mm scheme results in more calls to HDD?

from mac optimizations guidelines:
http://developer.apple.com/documentation/Performance/Conceptual/FileSystem/Articles/FilePerformance.html

#Minimize the number of file operations you perform. For more information, see “Minimize File System Access.”
#Group several small I/O transfers into one large transfer. A single write of eight pages is faster than eight separate single-page writes, primarily because it allows the hard disk to write the data in one pass over the disk surface. For more information, see “Choosing an Optimal Transfer Buffer Size.”
#Perform sequential reads instead of seeking and reading small blocks of data. The kernel transparently clusters I/O operations, which makes sequential reads much faster.