The
update Process
The update command is more than just a
command; it is also a daemon. When run as superuser (during system
initialisation) it will periodically flush all of the older dirty buffers out
to disk. It does this by calling a system service routine
that does more or less the same thing as bdflush.
Whenever a dirty buffer is finished with, it is tagged with the system time
that it should be written out to its owning disk. Every time that update runs it looks at all of the dirty buffers in the
system looking for ones with an expired flush time. Every expired buffer is
written out to disk. 
No comments:
Post a Comment