Using File Bit Flags for Other Purposes

Question

I'm conflicted on this one. Here's the situation -

I have a bunch of PDF files arriving in a folder from an external application (beyond my control) on a Windows 2003 server. These PDF files eventually get printed by my application by looking at the dates on the file (i.e. "print today's PDFs"), and then are generally held for a month or so before being deleted. They can be automatically printed, or manually printed by a user.

As a convenience to the user (data we don't act upon) I'd like to show which files have already been printed. This application has been fairly standalone and very simple, the way I like it.

Should I consider using file bits (i.e. Archive bit or something) to differentiate between files that have been printed and take the chance that a backup program could run, -or- increase the testing/maintenance overhead of the application by creating a data source for it (cross-reference table in XML) and introduce another "moving piece"?

Answer 1

Using file bits for this is probably not the right approach - things like Archive are intended for use by system utilities that may change the bits beyond your control.

You should either keep a separate record of what's been printed (in a file or the registry), or perhaps move them into separate physical folders to differentiate them (while your application can just present a unified view of the two folders to the user.)

I wouldn't be worried about the perf overhead of keeping a separate record of this - it only has to be updated when users are printing, and printing will definitely be more expensive than updating a file.

Answer 2

You could consider keeping the information self-contained, without misusing flags, by using NTFS alternate data streams.

Answer 3

If it were me, I would not use file flags for something which they're not intended. Some other process could set the flags outside of your control and you wouldn't know what to do. Create a new moving piece that is explicit and easy for another developer to know what is going on.