Shared Operating System Directories
Computer operating systems include the capability for users to designate directories for sharing across a local area network (LAN). In Microsoft Windows, such directories are called "shared folders" and can be configured by changing the folder's settings in Windows Explorer. In Unix, network administrators can create designated directories on file servers that users can in turn "mount" onto their client workstation using technologies like Network File System (NFS).Windows Public Folder
Starting with Vista, Microsoft Windows provides one special, pre-installed folder called "Public" designed to enable file sharing between multiple users logging into the same PC. On the local file system, this folder resides at C:\Users\Public, a location that may also be reached via the Favorites list in Windows Explorer. The Public folder is not shared by default, but an administrator can easily enable sharing as follows:-
1. Open Windows Control panel and navigate to the "Network and Sharing Center" section
2. Click "Change advanced sharing settings" on the left-hand channel menu
3. In the "Public folder sharing" section, click "Turn on sharing… ."
4. Click the "Save Changes" button at the bottom of the window.
Underneath the top-level Public folder, Microsoft auto-populates a list of sub-folders named Public Desktop, Public Documents, Public Downloads, Public Music, Public Pictures and Public Videos. These sub-folders are intended to help users organize their files by type making them easier for others to browse. Administrators are free to add their own subfolders and re-organize the directory tree to suit their preferences. When sharing is activated, all files and folders within the Public folder tree can be accessed by anyone logged into the PC.
Starting in Windows 7, Microsoft included Windows 7 HomeGroup functionality into the operating system, expanding on the capabilities of public folders. Both HomeGroup and the Public folder system are supported in current versions of Windows.
Outlook/Exchange Public Folders
The Microsoft Exchange family of email servers also supports the concept of public folders for users of Microsoft Outlook mail clients. An IT administrator creates and manages their own set of public folders (and sub-folders) in Exchange and makes them available to Outlook users. These exist independently from the Public folder of the Windows operating system.Public folders in Outlook/Exchange work like a shared mailbox. They can contain email messages from users, a shared Outlook calendar, shared contacts and email form pages. Network administrators can control which groups of users have access to each of these public folders individually. The Exchange system includes built-in mechanisms to automatically synchronize the contents of public folders between mail servers across an organization.

