Offline Files is a new feature in Windows 2000 that allows client machines to cache files and then work with those files offline. Although conceptually similar to My Briefcase, Offline Files goes a step beyond by handling synchronization (via Synchronization Manager) and version checking automatically. Before looking at how a user interacts with Offline Files, it is important to understand how they are configured. Since these files must first be accessible over the network, the folder in which the files exist must be shared. You also enable caching properties via the Caching button on the Shared folder tab. For a folder shared off Windows 2000, three settings are available:
- Manual Caching for Documents: This is the default setting, and documents will only be cached if the client explicitly chooses to make the folder or files within it available offline.
- Automatic Caching for Documents: This option will automatically cache any files opened from the shared folder onto the client machine. By default, up to 10% of the drive can be used for these ‘temporarily’ cached documents, though this setting can be changed. Note that files follow a ‘longest unused, first out’ rule as the cache fills.
- Automatic Caching for Programs: This option client-side caches applications that have been configured to run over the network, making them available offline.
If you wish to disable caching of a folder, simply clear the ‘Allow caching of files in this shared folder‘ checkbox.
If a folder has been set for Automatic Caching for documents, the files opened will be automatically cached as opened without user interaction, and can be accessed using the original path (for example a mapped drive letter or UNC path) even while offline. If the user wishes to make a folder available offline, they can accomplish this by browsing to the folder, and then right-clicking on the appropriate file or folder and choosing ‘Make Available Offline’. The user opens these files either by browsing to the original path (as mentioned before) or via a shortcut folder called Offline Files that can be placed on the desktop (via the Offline files Wizard, which will run the first time a user chooses to make a file or folder available offline). Note that the files are actually cached into a special folder under %systemroot% called CSC. If you can’t find the folder, that’s because it’s marked both System and Hidden, and you must choose to show protected operating system files as well as hidden files. You will not be able to open files directly from CSC, and should not make any changes in this folder.
Some important last words on Offline Files:
- Files shared from any SMB-based OS can be made available offline (including Win95 and NT 4, for example).
- You can control when synchronization happens. Options include at logon/logoff, when the computer is idle, at scheduled times, or when initiated manually.
- The synchronization process will check to see whether the online version of a file that you edited while offline has changed since the last synchronization (for example, if someone edited a file after you made it available offline). If a conflict exists, you would be prompted as to whether your version, the network version, or both versions (with one renamed) should be kept. If no conflict exists because the online version hasn’t changed, it will simply be overwritten by your newer version.
- Offline files is enabled by default on Windows 2000 Professional. The client settings f or offline files (such as whether they can be used) are controlled via Tools – Folder Options – Offline Files from Windows Explorer.