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Both of these capabilities translate into reduced cycles for creating, modifying, and distributing groupware applications. That means end-users can build applications that are valuable to them without having to wait for a response from their IS departments. Even if an application turns out to be less useful than the creator hoped it would be, the development cost is minor.
The IS department can also benefit because it can customize those applications that do turn out to be worthwhile, since forms created or modified with Microsoft Outlook are extensible with Visual Basic Script programming system. In addition, Outlook Forms can be further extended with other programming tools such as Visual C++, ActiveX Controls, and Java. By using the Microsoft Exchange Server replication engine, revisions and new applications can be deployed inexpensively as well.
The speedy application design and delivery process made possible by Microsoft Exchange Server enables the people who have the best understanding of the functionality needed to respond quickly to market requirements. As a result, an organization can reduce the costs of adapting and rolling out those applications. Whenever an application is rolled out within an organization, it is usually only a matter of time before the applications developer hears from users about how it could be improved. Many applications provide limited functionality once the barrier is reached, they cannot be customized any further and require redesign from scratch with a more powerful tool.
Thus, forms designed by end-users can be customized by professional developers using the full power of Visual Basic Script. Other workgroup application design tools either require a high degree of programming skill or quickly run out of steam, as a particularly useful application requires additional functionality. Microsoft Exchange Server opens the door between end-user application design and the full power of the Windows APIs available through more powerful programming languages.
Exchange Server takes these forms even further by automatically rendering them to the Web as HTML forms. By leveraging a technology known as ActiveServer Pages, included with the Microsoft Internet Information Server, forms and the information in them can be seen by any user accessing Exchange from a browser anywhere on the World Wide Web (if they have the appropriate permissions of course).
The MAPI subsystem is the infrastructure on which Microsoft Exchange Server is built. Messaging client applications communicate with service providers running on the server through the MAPI subsystem. Through broad publication of Microsoft messaging APIs, and because of the robust messaging and workgroup functionality defined in them, MAPI has become a widely used standard throughout the industry for messaging and groupware clients and providers.
MAPI-compliant clients span a variety of messaging- and workgroup-based applications and support either Windows 32-bit MAPI applications on Windows 95 or Windows NT, and 16-bit MAPI applications running on Windows 3.x. Each of these types of applications can access the service provider functionality needed without requiring a specific interface for each provider. This is similar to the situation where applications that use the Microsoft Windows printing subsystem do not need drivers for every available printer.
Messaging applications that require messaging services can access them through any of five programming interfaces:
Client requests for messaging services are processed by the MAPI subsystem either as function interface calls (for sMAPI or CMC) or as manipulations of MAPI objects (for OLE Messaging or MAPI itself) and are passed on to the appropriate MAPI-compliant service provider. The MAPI service providers then perform the requested actions for the client and pass back the action through the MAPI subsystem to the MAPI client.
Third-party programming interfaces that can be built upon MAPI are frequently employed. Because MAPI is an open and well-defined interface, a proprietary third-party API can be implemented on top of MAPI without having to revise the MAPI subsystem itself. Thus, customers and vendors can implement their own MAPI solutions that meet their particular needs without incurring the development costs that would otherwise accrue on other messaging infrastructures.
Extensive built-in support for the Internet in the Microsoft Outlook Clients, as well as the Microsoft Exchange Internet Mail Service, Microsoft Exchange Internet News Service, and Outlook Web Access, makes it easy for organizations to use the Internet as a communications backbone, to make Internet newsgroup data available to their users through public folders, and to make messaging and public folder information available to the ever-growing numbers of Internet Web users.
The Microsoft Exchange Internet Mail Service provides high-performance multithreaded connectivity between Microsoft Exchange Server sites and the Internet. It also supports MIME and UUENCODE (and BINHEX for Macintosh) to ensure that attachments arrive at their destinations intact. Built-in message tracking helps ensure message delivery. Standards-based digital encryption and digital signatures ensure message security.
These capabilities make it possible for organizations to use the Internet as a virtual private network to connect Microsoft Exchange Server sites over the Internet and to route messages using the TCP/IP SMTP or X.400 protocols. You can easily control who sends and receives Internet mail by rejecting or accepting messages on a per-host basis.
The Microsoft Outlook Clients include built-in Internet mail standards to allow users, connected locally or remotely, to reach other Microsoft Exchange Server sites and virtually anyone else using any Internet service provider. Native MIME support allows files to be transported reliably over the Internet. Support for Post Office Protocol, Version 3 (POP3), PPP, and IMAP4 ensures compatibility with all SMTP E-mail systems.
The Microsoft Exchange Inbox a version of Microsoft Exchange Client that does not include Microsoft Exchange Server-specific functionality is built into the Windows 95 operating system. This feature makes Internet mail easy to set up and access. Any user with an Internet mailbox via POP3 can use the Internet Mail Driver for Windows 95 in the Microsoft Exchange Inbox. Similarly, any client that supports POP3 can connect to a Microsoft Exchange Server. Outlook Express is an Internet Mail and News Client that ships with Microsoft Internet Explorer 4.0 and supports the SMTP/POP3, LDAP, NNTP, and IMAP4 protocols.
The Microsoft Exchange Inbox and Microsoft Outlook clients can also leverage the Internet in another way as an alternative to dialup connections.
Outlook clients and Microsoft Exchange Server both have built-in support to connect to each other securely over the Internet. Mobile users can use a local Internet service provider (ISP) to connect to the Microsoft Exchange Server site located back in their organizational headquarters. Once this connection is established, users have full access to all server-based functionality, including directory services, digital signature and encryption, group scheduling, free/busy checking, and public-folder applications.
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