FLUSH Call

A call that MFS programmers will find executed often is FLUSH. This call is used by OpenInsight to alert all filing systems that they should flush any cached information to disk. FLUSH is called when the system resets, when a file or volume is detached, or when logging off. OpenInsight's indexing system also calls FLUSH.

The FLUSH call is a direct call to each filing system currently installed (see INSTALL, above), rather than a call to a specific file. An MFS should therefore not attempt to pass a FLUSH call through to the next filing system. The BFS argument that normally contains a full list of filing systems will contain only the name of the MFS being called. Attempts to pass the call through to the next BFS will result in load errors.

A MFS does not typically need to include logic that causes flushing. Of course, an MFS can use the FLUSH call for its own purposes, including any type of system cleanup required for an MFS.

Even if the MFS does not use the FLUSH call, it should include this logic:

FLUSH:

STATUS = 1

RETURN

Status is always set to true, and that there is no call to the next filing system.