Microsoft KB Archive/71350

Project: “Resource Sharing” Application Note, Complete Text

PSS ID Number: Q71350 Article last modified on 10-20-1995

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WINDOWS

= SUMMARY =

A powerful feature of Project for Windows is its ability to share resources across multiple projects. This feature is useful for preventing resource overallocation when the resources are involved in multiple projects. The application note “Resource Sharing” (WP0409) will help you successfully share resources and prevent potential problems.

To obtain this application note, call Microsoft Product Support Services at (206) 635-7155.

This application note is also available in the Software/Data Library and can be found by searching on the word WP0409, the Q number of this article, or S12977. WP0409 was archived using the PKware file-compression utility.

= MORE INFORMATION =

The following is the complete text of the application NOTE:

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========================================================= WP0409: RESOURCE SHARING ======================================================================

= Introduction =

A powerful feature of Project for Windows is its ability to share resources across multiple projects. This is useful in preventing resource overallocation when the resources are involved in multiple projects. This application note is intended to help you successfully share resources and prevent some potential problems.

= Resource Sharing Concepts =

Overview
Microsoft Project for Windows stores resource information in resource pools. Each project can have its own resource pool, or it can share another project’s resource pool. To use resources from another project’s resource pool, use the Resources command from the File menu.

[Dialog Box graphic deleted] Once this command has been executed, a link is created between the project with the resource pool and the project file that is using the other project’s resource pool. For more information on resource sharing, see the “Sharing Resources Across Multiple Projects” section in the “Microsoft Project for Windows Feature Guide.”

Links
Two kinds of links are created between Project files. The resource sharing link is the one discussed here, and the other is the link that is created by designating a subproject. These links are displayed by choosing Links from the File menu. The way to determine if the link displayed is a resource link or a subproject link is by selecting the link and observing the Change button. If the button is available, the link is a subproject link.

If the Change button is not available (that is, it appears dimmed), the link is a resource link.

When you exit Project or close any files using resource sharing, you will be prompted to save the files. You must save these files to exit normally from Project.

Saving is crucial to maintaining these files in working order. If you choose Cancel, the files will not close, and you will not be able to exit from Project.

Resource Links
Project for Windows tightly maintains the data integrity of linked resource files. Once a link to a shared resource pool is created with the Resources command (from the File menu), Project saves an “edition number” with each file involved in the resource link. When a file is opened that is using another project’s resource pool, Project checks to make sure that the resource pool is open and, if it is not open, Project returns the following error message (where “D:WINPROJ.MPP” is used as an example):

Cannot find shared resources. Resource pool (‘D:WINPROJ.MPP’ when last saved) must be opened first.

If the resource pool is open and the edition numbers match, the file is opened. If the edition numbers do not match, then Project recognizes that the data in the shared resource structure is not up to date. Project returns the following message:

Cannot use resources from ‘D:WINPROJ.MPP’, file version does not match pool.

At this point, the project file that is using shared resources cannot be opened. This limitation is by design: Project is designed to report only accurate information.

Because Project requires that each file using resource sharing be saved before closing or exiting the program, the edition number should never become mismatched during normal operation of the program. The number could, however, become mismatched when one file is saved and the other isn’t and the computer is rebooted or turned off, the power fails, or the program hangs. Because accidents can happen, it is highly advisable to make regular backups of files that share resources in a backup directory or on a floppy disk while the files are still in working order. If you encounter a problem, you can replace the files with the backup copies and re-create only the changes made since the last backup. To back up files, use the Windows 3.00 File Manager, the Copy command from the Windows 2.x File menu, or the DOS Copy command (or any copy utility) at the DOS prompt. Be sure to copy the resource pool and all linked files when making backups.

Important: Do not use Save As from the File menu in Project while using resource sharing. The Save As command disables the link between the file and its resource pool, because the original file will be closed without saving and the file with the new name will be the active file with the resource link. If you try to open the original file, you will get the “…file version does not match pool” error message. The Create Backup option in the Save As command is also not useful in this case because it simply renames the currently saved edition of the file to the backup and saves the current edition in use as the .MPP file.

Consequences of Using Save As
Not only will Save As from the File menu disable links for files using another project’s resource pool, but it can also have other consequences. The resource link between the files doesn’t only look at the filename. It looks at an internal filename that is not visible to the user. The Save As function doesn’t change this internal name; therefore, when you clone a project file, you end up with two files with the same internal name. The next time you open the project, you will encounter the following error message:

Cannot open resource pool; it is a duplicate of one already open.

In this case, you would have two files with seemingly different filenames but with, in fact, the same internal filename. To create a clone of a file, use the Copy and Paste commands from the File menu.

Backing Up Resource Sharing Files in MPX Format
If a project file that is using resource sharing is saved in MPX format, it will be saved as an independent file. All resources being used from the shared resource pool will be preserved and saved in the file. When the file is reopened, it will have all of the resources in its own resource pool. This allows the file to be opened even if the linkage is damaged, because the file does not depend on the edition number. The file can be reattached to the pool by using the Resources command from the File menu. The pool can also be saved in MPX format. This removes all of the links to files using resource sharing; therefore, you must ensure that each file using the pool is saved in MPX format before the file containing the resource pool is saved. For more information about the MPX format, see the “Exchanging Information” section of the “Microsoft Project for Windows Reference.”

Resource Sharing Without a Resource Pool
The capabilities of Project for Windows allow 2000 tasks and 2000 resources in each project file. Within these limits, you can use the outlining feature to set up multiple individual projects in the same file. With all of these projects summarized in one file, you can use the resources attached to the file and avoid using a shared resource pool from another file.

To create multiple projects in the same file, follow these steps:


 * 1) Set up a task that has the name of the project that will be the summary task.
 * 2) Type in the individual tasks for the project.
 * 3) Highlight from the first task of the project to the last task and demote the tasks (by clicking on the right arrow icon or by pressing ALT+SHIFT+RIGHT ARROW).
 * 4) Leave a blank line before typing in the summary task for the next project.

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Copyright Microsoft Corporation 1995.