From the earliest days, e-mail messaging has been an important communication tool for Microsoft. Microsoft established the first company-wide messaging environment in July 1982 based on Microsoft XENIX (a UNIX version for the Intel 8088 platform). This environment evolved over more than a decade into a large and distributed infrastructure that was increasingly difficult to manage. By migrating to Microsoft Exchange Server version 4.0 in 1996, and subsequently upgrading to Microsoft Exchange Server version 5.0 and Microsoft Exchange Server version 5.5 in 1997, Microsoft IT achieved significant improvements in terms of functionality, maintainability, and reliability.
At the beginning of the new millennium, Microsoft IT operated a messaging environment that included approximately 200 Exchange Server 5.5–based servers in more than 100 server locations with approximately 59,000 users. The changes continued with the upgrade to Microsoft Exchange 2000 Server, released in October 2000. Exchange 2000 Server so tightly integrated with the TCP/IP infrastructure, Windows, and Active Directory that Microsoft IT no longer could manage the messaging environment as an isolated infrastructure.
The shift of Microsoft IT toward a service-focused IT organization was also noticeable in the designs and service level agreements (SLAs) that Microsoft IT established with the rollout of Exchange Server 2003, released in October 2003.
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MCTS | Exchange Server