Microsoft Office 2000/Visual Basic Programmer's Guide   

Using Operating System Access Control

You can control access to files and folders by using Microsoft Windows NT Server, Microsoft Windows NT Workstation, Microsoft Windows 95, or Microsoft Windows 98. Under Windows NT Workstation and Windows NT Server, you can control access to local folders on an NTFS-formatted hard disk and to shared folders; with Windows 95 and 98, you can control access only to shared folders.

Windows NT Workstation and Windows NT Server

You can control access to folders in Windows NT Server and Windows NT Workstation by setting access permissions. Additionally, if the files are located on an NTFS-formatted hard disk, you can define access permissions for individual files. Under both Windows NT Server and Windows NT Workstation, you can define access permissions for folders and files that are shared across a network, as well as folders and files on local NTFS-formatted drives that are shared by multiple users logging on to the same computer by using different local user account names.

To set access permissions for a folder located on an NTFS-formatted hard disk in Windows NT Server and Windows NT Workstation, right-click the folder, click Properties on the shortcut menu, and then click Permissions on the Security tab. You can share the folder on a network by using the settings on the Sharing tab, but leave the Permissions settings on the Sharing tab at their default (Everyone – Full Control), and make final permission settings by using the Permissions button on the Security tab. Permissions settings made by using the Security tab override settings made on the Sharing tab.

To set access permissions for an individual file located on an NTFS-formatted hard disk, right-click the file, click Properties on the shortcut menu, and then click Permissions on the Security tab.

If you are setting permissions for a file that needs to run code, such as a copy of Normal.dot or a template containing macros in a protected folder, you must provide at least Read permissions. If your solution creates additional files, such as log files, you must provide at minimum the Add & Read permission. If your solution uses an Access add-in that you want to install in a protected folder, you must also provide at least Add, Read, and Write permissions, because even if you aren't adding data to an .mdb file, users must be able to create and write to an .ldb file before the .mdb file can be opened.

For more information about setting access permissions in Windows NT Server versions 4.0 and 5.0 and Windows NT Workstation versions 4.0 and 5.0, search the Help index for "permissions." You can also find more information about setting access permissions in Windows NT Server 4.0 in the Windows NT Server Concepts and Planning guide, Chapter 4, "Managing Shared Resources and Resource Security."

Other network operating systems, such as Novell NetWare, provide similar features to control access to files. For information about how to control access to files with these network operating systems, refer to the documentation for these products.

Windows 95 and Windows 98

You can control access to folders that are shared across a peer-to-peer or server-based network in Windows 95 and Windows 98. Before you can do this in Windows 95 and 98, you must use the Network icon in Control Panel to enable file sharing by clicking the File and Print Sharing button on the Configuration tab. You can use options on the Access Control tab to determine whether to use share-level (password) or user-level (users and groups) access control for shared folders. The user-level access control option is available only if the computer is connected to a network server where user accounts reside, such as a Windows NT domain controller. In Windows 95 and 98, there is no way to control access to folders on local drives that are shared by multiple users logging on to the same computer by using different user account names.

To set access permissions for a folder shared across a network in Windows 95 or 98, right-click the folder in Windows Explorer or My Computer, and then click Sharing on the shortcut menu. Click Shared As, and then define access permissions for the folder. For more information about setting access permissions in Windows 95 and 98, search the Microsoft Windows Help index for "permissions."