Notification
Notification is a means by which an application can receive a message whenever a certain file of interest is modified. By establishing "hot links" between applications, notification allows a change made to a file with one program to be automatically reflected in another application that is using the same file.
Hot links allow a change made to a file with one program to be automatically reflected in another application which is using the same file.
An example would be a paint package in which the user could save a brush and, using notification, automatically have an image processor application modify the brush and return it in a separate file. The scenario would work like this:
1. PAINT PACKAGE
- Writes brush to file named T:brush.
2. IMAGE PROCESSOR
- Gets notification that T:brush has been updated.
- Reads T:brush into work area.
- Alters brush using an image processing feature.
- Writes brush out to T:brush.mod.
3. PAINT PACKAGE
- Gets notification that T:brush.mod has been updated.
- Reads T:brush.mod into brush area.
There is only one style standard to worry about with notification: keep RAM usage reasonable. Because RAM is a limited resource, applications that have very large amounts of data should not store directly in RAM:.
Notification may not work in a network situation because it is not implemented with some file systems. It does work on RAM:, FFS and OFS.