What is the Exchange Installable File System (ExIFS) and Web Storage System (WSS)?

A. After installing Exchange 2000, you'll notice a new drive letter on your system, the M drive (or if M is already in use, the system uses the next available drive letter). This drive interface provides a simple way to use Exchange as a powerful file repository for any application and allows full access to user mailboxes and public folders. Below is a directory listing for my M drive:

M:>dirVolume in drive M is ExchangeVolume Serial Number is 00A9-8AC7Directory of M: 30/01/2001 10:16  SAVILLTECH.COM0 File(s) 0 bytes1 Dir(s) 3,333,074,944 bytes freeM:>cd savilltech.comM:savilltech.com>dirVolume in drive M is ExchangeVolume Serial Number is 00A9-8AC7Directory of M:savilltech.com30/01/2001 10:16  . 30/01/2001 10:16  .. 30/01/2001 10:16  MBX30/01/2001 10:16  PRIVATE FOLDERS30/01/2001 10:16  PUBLIC FOLDERS0 File(s) 0 bytes

Notice the first level of the M drive is the default recipient policy domain name, savilltech.com. If you modify the SMTP address generation rule of the default policy SMTP, the system updates the domain name that ExIFS presents.

Under the first level of the M drive, we see the MBX folder, which holds the user mail boxes, and the PUBLIC FOLDERS folder, which provides access to public folders on the system. The system still enforces all regular ACLs when you view the Exchange information via the M drive.

You can also create shares based on folders within the M drive. However, rebooting the system loses them, so if you want them to be persistent, you need to create a batch file that automatically recreates them each time the system starts up. An alternative is to share Exchange resources via HTTP/WWW Distributed Authoring and Versioning (WebDAV) and use Web Folders to access the information, as described in How do I create a Web folder?.

ExIFS relies on the WSS, which consolidates the file system, database, and collaboration services into one server system. You can access the WSS via several interfaces, including Messaging API (MAPI) clients, HTTP, XML, WebDAV, OLE DB, ActiveX Data Objects (ADO), and standard Win32 API calls. These interfaces let the ExIFS offer M drive-based resource access.

The WSS provides one repository for managing multiple types of unstructured information within one infrastructure and lets you store all types of file formats. Every item in the WSS is URL-addressable and fully supports semistructured data, such as documents, contacts, messages, reports, HTML files, and Active Server Pages (ASP) pages. For example, to access my calendar via the Web I can use

http://[Server Name]/Exchange/MBX/savillj/calendar/

Using the ExIFS, I would use the following statement:

M: savilltech.comMBXsavilljcalendar

The available features are practically limitless, and you can easily create Web-based forms to interact with the WSS to enable easy updates and retrieval of information. For more information, visit the Microsoft Developer Network (MSDN) Web site.