Article 4 of 7

The Flow in Practice

There are two comprehensive architectural approaches to JDF. One approach is decentralized where the actual JDF file physically moves from one program to another. This is a rather simple way to implement JDF but includes with it a number of disadvantages. For example, it is not possible to control who is allowed to change information in the file or to know which file is the most current.

It is also hard to safely plan overlapping processes. These problems, of course, become more evident the more extensive the flow is. But if there is only one place to send the file to, the permissions, for example, are not a problem.

The other approach is considerably more complicated to implement and has a centralized architecture. However, this approach has several advantages when compared to the decentralized approach. In the centralized architecture, a Master JDF file is created by the management system. The file and its structure are stored in a central database and are administrated by the management system.

The database contains advanced mechanisms that can control the accessibility of the data. Functions such as back up and the handling of uncompleted transactions are also standard. This means that parts of the JDF file can be checked out by different software, changed, commented on, and then checked back in again. Thanks to the database’s accessibility control, everyone can read the file, but only the one who has checked out a specific part can write in that part.

If one compares the two alternatives, one can establish that the centralized variant has the following advantages over the decentralized variant:

• The JDF file is constantly ”guarded”.

• Well-defined routines for checking out and in parts of or the entire JDF file.

• Clear permissions, who is allowed to do what.

• Parts that are checked out are protected and can be blocked for other software and users.

• Easier to maintain.

One should bear in mind that the centralized approach is considerably more time-consuming to implement and it is doubtful that suppliers of both machines and software have fully realized this approach. However, it can be of interest to be aware of both variants.