Offline Files is another in the long list of new features Microsoft boasts of in the Windows 2000 documentation. Both Windows 2000 Professional and Server support the Offline Files feature, but many users of the operating system remain unaware of what it is, how it works, and how it can benefit them.
In this Daily Drill Down, I will introduce you to the Windows 2000 Offline Files feature, which is an integral component of the multilayered IntelliMirror technology that allows administrators to exercise more control over network resources and provides users with convenient ways to work with network data and programs.
What is Offline Files?
Microsoft’s IntelliMirror is a group of individual operating system features that provide four basic services:
- Better management of user data
- More control over user settings
- Easier automated installation and maintenance of software
- Easier remote automated deployment of the operating system
The Offline Files feature is designed to improve management of user data, along with the Synchronization Manager, Roaming Profiles, the Disk Quotas feature, and the ability to control user data via Active Directory and Group Policy.
Offline Files allows you to keep using network files, folders, and applications when disconnected from the network. To the user, this is transparent; you will still have the same access permissions to the files and folders that have been made available offline as when you are connected to the network. Best of all, when you reconnect, all the changes you have made to those files will be made to the files on the network, via offline file synchronization. Any file or folder that is shared on a Microsoft network can be made available offline, as long as the computer on which they are stored supports SMB-based file and printer sharing (this includes all Windows 9x and NT4/2000/XP computers).
Benefits of Offline Files for mobile users
The biggest beneficiaries of the Offline Files feature are users of mobile computers who frequently connect and disconnect from the network to use their computers at home or on the road. Now mobile users can be assured that they are working with the most up-to-date versions of network files, navigate through mapped network drives even when disconnected, and easily synchronize changes with the network when they plug back into the network.
Because mobile users often have to contend with disk-space limitations on laptops or notebooks, the Offline Files feature allows the administrator to specify the amount of space that can be used for automatic caching of offline files on the local computer (this does not limit the ability to store additional offline files manually). I will discuss how to configure cache limits later in this Daily Drill Down. The default configuration settings for Offline Files are, in general, optimized for the needs of mobile users.
Better than a briefcase?
In Windows 95/98 and NT 4.0, the Briefcase offered limited functionality for synchronizing files between two computers. Windows 2000 still includes the Briefcase, although it is no longer placed on the desktop by default (to create a Briefcase, right-click on an empty space on the desktop and select New | Briefcase from the right context menu).
The Briefcase works best when moving files between two computers that are connected via a direct cable connection such as a serial null modem cable, or to keep files transferred via floppy, Zip/Jaz, CD, or other removable storage device in sync.
Offline Files was designed with the network in mind and offers more convenient functionality when working with files stored on a network server. With Offline Files, multiple users can modify files while working offline, and the Synchronization Manager will allow the user to choose how the network and local copies will be updated when the offline users reconnect to the network. Windows XP has dropped support for the Briefcase and uses Offline Files exclusively.
Configuring Offline Files in Windows 2000 Professional
There are three steps involved in setting up your Windows 2000 Professional computer to use Offline Files:
- Enable the Offline Files feature.
- Make one or more files or folders available offline.
- Configure Offline Files settings to control caching options and disconnection response.
Enabling Offline Files
Before you can make any content available offline, you must enable the use of Offline Files on your computer. To do so, open the My Computer desktop icon, select the Tools menu at the top of the window, and choose Folder Options. In the tabbed dialog box, select the Offline Files tab, as shown in Figure A.
|The first step in using Offline Files is to enable the feature on your computer.|
Check the box to enable Offline Files. This sheet is also used to configure Offline Files settings, (discussed in the next section).
If you are using Windows 2000 Professional, Offline Files will be enabled by default (it is disabled by default on Windows 2000 Server). However, you will not be able to work offline until you have designated at least one file or folder to be available offline.
Configuring Offline Files settings
On the Offline Files properties sheet, in addition to enabling Offline Files, you can also specify:
- Whether the system should synchronize all offline files before logging off when you log off, restart, or shut down the computer. This will ensure that you have the most up-to-date versions of the files you have designated to be available offline.
- Whether to enable reminders, which will cause a notification balloon to appear over the system tray when a computer goes offline. If you select this option, you can also specify, in minutes, how often the reminder balloon should be displayed after the computer goes offline.
- Whether a shortcut icon for the Offline Files folder should be created on the desktop.
- The amount of disk space allocated for storing offline files that are automatically cached because an administrator has specified that they be made available offline. This does not affect the files that the user has made available offline.
Windows XP offers another check box on this sheet that is not included in Windows 2000: You can choose to encrypt the offline files to secure the data.
You can also use these buttons at the bottom of the sheet:
- Delete Files: Use this button to remove selected offline files on the local computer. (This does not delete those files from the network location.)
- View Files: Use this to view the contents of the Offline Files folder, which shows all files that have been made available offline, along with their type, synchronization information, availability, access, location, size in kilobytes when last modified, and the status of the server.
- Advanced: With this, you can choose what will happen if you are working online (connected to the network) and the connection is lost. Your choices are to have the system notify you that you are offline and allow you to continue working with network resources offline, or to never allow the computer to go offline, as shown in Figure B.
|You can specify what happens when your connection to a network computer is lost.|
On the Advanced Settings sheet, you can create an exception list, where you designate the behavior when a particular server gets disconnected. This is also shown in Figure B; the default behavior when a network connection is lost is to notify and begin working offline, but if a connection to the computer named Isaserver2 is lost, the setting specifies that this computer should not go offline.
Making files and folders available offline
To make a file or folder available offline, it must first be shared. Remember, only a member of the Administrators or Power Users groups in Windows 2000 Professional can share folders by default.
After enabling Offline Files, all you have to do is navigate to the selected shared file or folder in My Computer or My Network Places, highlight the file or folder name, either select the File menu or right-click the file or folder, and choose Make Available Offline, as shown in Figure C.
|You can make a shared file or folder available offline once Offline Files is enabled.|
It is important to note that you cannot share an individual file—you must share a folder or drive. However, when you share a folder, the files inside that folder are shared, and you can then individually make any of those files available offline.
Setting caching options on shared folders
Offline Files works by creating a cache on the computer’s local hard disk and storing the shared network files that are designated as offline files in this cache. You configure the caching options for each shared folder made available offline. The caching options are set from the Shared Folders node in the Computer Management MMC (accessed by right-clicking My Computer and selecting Manage). Right-click the shared folder for which you want to set caching properties and select Properties. On the General tab, click the Caching… button.
The Caching Settings properties box is shown in Figure D.
|Caching properties are set for each shared folder individually.|
Enable caching of the shared folder by selecting the check box. There are three options available to control how the files in the folder will be cached:
- Manual Caching For Documents: With this option, the only documents that will be cached are those that the user specifically designates to be available offline.
- Automatic Caching For Documents: With this option, when a user opens a file in this shared folder, it will be automatically downloaded and made available offline without the user specifying that it be an offline file. Older copies of a file will be deleted automatically to make room for files that have been accessed more recently. With this option, a file that the user has not opened while online will not be available offline.
- Automatic Caching For Programs: All files in the folder will be made available offline. This option is used when the data in the folder is read-only, as with shared network applications. It should not be used if users will change the data in the folder.
The default caching setting is Manual Caching For Documents.
Using Offline Files
After you have set up the computer to enable Offline Files and made the selected files or folders available offline, other users can connect to the offline files and work with them over the network, then continue working with them after the connection between your computer and theirs is broken.
If configured to display a balloon notification, when the network connection is broken, the user will see an Offline Files icon appear in the status area to the right of the taskbar buttons on the Windows 2000 taskbar.
When the network connection is restored (for example, when you plug your laptop back into the docking station or plug a live Ethernet cable into its PC Card NIC), the status bar information will change, and modifications that you have made to offline files since the disconnection will be updated to the network files automatically.
Synchronizing offline files
You can synchronize offline files manually. You can also schedule them to be synchronized at a specified time, using the Synchronization Manager.
There are two types of synchronization:
- Full synchronization: A full sync takes more time, but it ensures that every file made available offline is the most up-to-date version.
- Quick synchronization: A quick sync will provide you with a full version of each offline file, but it may not be the most up-to-date version. It is, however, much faster to perform.
To open the Synchronization Manager, select Start | Programs | Accessories | Synchronize. The Synchronization settings that can be configured include:
- Items that should be synchronized when you log on or off. You can specify that this occur automatically or that the system prompt you before synchronizing.
- Items that should be synchronized when the computer is idle. Using the Advanced button on this tab, you can set an idle time (in minutes) when synchronization should occur and how often it should take place while the computer remains idle, as shown in Figure E.
|You can control how idle time synchronization takes place.|
You can prevent synchronization from occurring while your portable computer is running on battery power, to avoid draining the batteries.
Using the Scheduled Synchronization tab, you can set times for synchronization to occur automatically. Clicking the Add button on this tab will invoke the Scheduled Synchronization Wizard, shown in Figure F.
|The Scheduled Synchronization Wizard helps you set up automatic synchronization.|
With the Wizard, you can select a time and day when you want the synchronization to start and how often synchronization should occur. You will then be asked to give the synchronization job a name, and it will be entered into the list of current synchronization tasks.
You can manually synchronize an individual file or folder by selecting it in Windows Explorer or My Computer and selecting Tools | Synchronize.
Understanding and resolving file conflicts
If more than one person works with the same offline files, the possibility of file conflicts arises. There can be differing versions of the file to which different modifications have been made. When you synchronize files, those that you have modified since disconnecting from the network will be compared to the versions of those same files on the network server. Your changes will be copied to the network versions—if no one else has modified the network files while you were working offline.
However, if someone else did change the files during that time, a file conflict arises. Which version should be kept on the network—the one copied to the network while you were offline, or the one containing the modifications you made while offline? You will be asked to choose one of the following:
- Keep Your Version Of The File
- Keep The Version On The Network
- Keep Both Versions
If you elect to keep both versions, you will need to give your version a different name. Both versions will be saved to your local disk and the network server.
The Offline Files feature in Windows 2000 supplements and, in many cases, will replace the familiar Briefcase file-synchronization tool. Offline files make life easier for users who must frequently connect to and disconnect from the network, such as mobile users. Offline files also give administrators more control over user data, as they can specify that certain files be automatically made available to users offline. The Synchronization Manager makes it easy to keep offline files updated, and the Synchronization Wizard allows you to schedule synchronization tasks to occur whenever you specify. In this Daily Drill Down, I have provided an overview of what Offline Files is, how it can benefit you, and how to enable, configure, and use Offline Files on your Windows 2000 Professional computer.
Debra Littlejohn Shinder, MCSE, MVP is a technology consultant, trainer, and writer who has authored a number of books on computer operating systems, networking, and security. Deb is a tech editor, developmental editor, and contributor to over 20 additional books on subjects such as the Windows 2000 and Windows 2003 MCSE exams, CompTIA Security+ exam, and TruSecure's ICSA certification.