In your work you may be surprised to see that your project file (the file with extension ‘.spp’ that contains all your specification data) is growing in size, even though have made only minor edits or header changes. This is because the Project Manager saves all the previous edits to a section since the NMS master was first added to the project. Although each section edit occupies only a few 10-K-bytes of data, over time the project may grow to an unmanageable size. Your project file can hold over 4000 copies of edited sections, which may occupy 100 Megs or more of data on your hard disk! There are a couple of useful ways to compress this data without losing valuable edits.
The first way is to use the SaveAs command to create a copy of the project. However, the new file is not an identical copy of your original file because the SaveAs command tries to remove seldom used or inaccessible data. The most common type of section data that is removed results from header changes: those copies of section files resulting from a global header command. You may have observed that when you issue a Header Change or Header Resize command, all the active sections in your project are duplicated with the new copies containing the updated header layout.
SaveAs will remove all the ‘hidden’ changed copies of section files resulting from a global header change. It will of course not remove the latest header changes if they are current. But as a result of its work you may notice a significant reduction in the size of your project file. The command will not disturb the chain of user edits to each section; it will remove the copies of sections resulting from header changes and as it were re-connect the chains of previous edits appropriately.