Exchange’s Core Components

Exchange has five key pieces. These core components are email,folders (the basis of information sharing), scheduling, forms, and connectors.

Email
Exchange offers rich-textemail capability. You can create email messages with text in multiple fonts,colors, and sizes. Messages can also contain in-place Object Linking andEmbedding (OLE) objects, such as Excel spreadsheets and Word documents, asScreen A shows. Exchange provides address books to store email addresses ofrecipients and information (e.g., company name, voice phone number) about them.You can set up multiple address books to store email addresses for variousrecipient groups. A convenient feature is the ability to send email to anyonewith an SMTP address. You can set up complete address books of friends, vendors,or customers who have an Internet address and send email to them from Exchange(although you lose some of the rich-text formatting unless the recipients arealso using Exchange or another Messaging API (MAPI) rich text-enabled client.)

Folders
Folders store informationin the database. They are containers for messages, forms, files, and otherfolders. Folders appear as a hierarchical tree to users, who can easily postinformation to folders and move information among folders.

The three folder types are personal, public, and mailbox. Personal foldersare for private use and are a good place to keep information you want on yourlocal machine or that you may need a password to access. Public folders are thebasis of information sharing. They provide public access to information, and youcan use them in groupware application development. Mailbox folders storeinbound, outbound, and server-based private mail. All these folders can haveoffline versions that Exchange can synchronize with the online folders­letting you work offline and easily keep your work in synch with online objects.(For an explanation of how to synchronize offline and online folders, see themain article.)

Exchange stores folders in its database, which uses the client/servermodel, which is optimized to speed email and groupware applications. A drawbackis that you can't read or update the Exchange database outside Exchange. No OpenDatabase Connectivity (ODBC) drivers or other database tools currently letdevelopers directly manipulate the Exchange database. However, Microsoft plansto add the ability to manipulate the Exchange database in the next release ofMicrosoft Access to let Exchange support more complex, database-centricapplications. For instance, a customer tracking system will be able to obtainthe customer's account balance from SQL Server or Access and post the balancedirectly to an Exchange folder.

Exchange's replication and directory synchronization features let you storethe same information on multiple servers, significantly improving the responsetime for accessing information that, for instance, may be on an Exchange serverin Europe and also on a server in the US. Replication can reduce communicationscosts, because you replicate data once, and then Exchange sends only updates andadditions.

Of course, Exchange wouldn't be as much fun if you couldn't do the oppositeof replication and configure folders for cross-server access, but you can. TheExchange administrator can designate public folder affinity, letting usersconnect to folders outside their designated site.

Naturally, Microsoft has created hooks from Microsoft Office applications toExchange. For example, you must have Microsoft Office version 7.0a to postdocuments directly to a public folder on Exchange. Also, your personal emailaddress book from Exchange is available on the Word toolbar. You can email adocument to another user by selecting Send from the File menu of an Officeapplication, or you can route a document to another user or users by selectingAdd Routing Slip, from the File menu. Routing lets you choose how to send thedocument to people­sequentially or all at once­and lets you controlthe revision capability along the route. You can put any Office document in anExchange folder, and you can use the properties of the document (e.g., theauthor, the revision date, or the cell of an Excel spreadsheet) in a view thatyou create to look at the folder (i.e., you can use the properties to search fordocuments in the folder).

Scheduling
Exchange uses MicrosoftSchedule+ 7.0a to support scheduling. Schedule+ is an easy-to-use program thatyou access from the Exchange client. Schedule+ lets you create and maintainschedules for people, teams, and tasks. The Meeting Wizard leads you throughchoices for who needs to attend; what resources (e.g., audio/visual equipment,meeting rooms, squirt guns) are necessary; and the meeting's location, time, andduration. The wizard then verifies the schedules of the required people andresources and the optional people and resources, and determines whether yourmeeting time is possible. If so, the wizard sends email notices to the attendeesand updates their personal schedule. Schedule+ is best when you can get everyoneto use it, but it's also great for individuals.

Forms
Exchange forms are simplyelectronic versions of the paper forms we all use each day to structure data forfast and efficient viewing. With forms, you can request vacation days, reporttravel-expense information, track phone messages, and so on. Unlike paper forms,however, these forms arrive via email through Exchange, and they can contain allsorts of other objects (e.g., OLE objects) and information. Forms can send amessage or post a message to a folder. If you post forms to a public folder, youcan view and search them for content. Exchange forms are a convenient andeasy-to-use front end for the Exchange database.

You can create custom forms that look exactly like your paper forms, andExchange can route these forms throughout your company. You create Exchangeforms with the EFD, which ships with Exchange. The EFD contains VB for MicrosoftExchange Server Version 4.0. VB generates source code that you compile toproduce the form. With VB 4.0's 16-bit version, you can extend forms you createwith the EFD.

Forms are the vehicle for extending Exchange. I think we will seesignificant application development based on Exchange forms, and third-partydevelopers will create entire applications and tools to support Exchange.

Connectors
Connectors let Exchangecommunicate with other Exchange and non-Exchange systems over many differenttransports, protocols, and mail systems. Exchange supports dynamic folderreplication between Exchange servers. This capability is useful, for instance,if you have a large company with multiple Exchange servers. Replicating foldersacross servers is faster and more secure than granting access rights to serverfolders.

Exchange uses several connector types. The site connector requires apermanent LAN connection and uses remote procedure call to connect Exchangeservers within the same site or LAN. A site connector is the fastest connectionpossible because you have no protocols to negotiate between servers.

The X.400 connector can connect Exchange servers to each other or toanother X.400-compliant mail system. An X.400 connector can use a public X.400connection that long distance telephone carriers provide.

The Dynamic Remote Access Service (DRAS) connector provides dial-up supportbetween Exchange servers. A DRAS connection is useful for low- to midbandconnections where the phone company connects servers through modems. You canspecify the connection interval. For instance, you can connect each hour duringthe work day and only twice during nonworking hours.

The Microsoft Mail connector links Exchange and Microsoft Mail. Thisconnector lets you move messages back and forth between Exchange and MicrosoftMail and lets you share Schedule+ Free/Busy schedule information to easemigration. (For an analysis of the Microsoft Mail connector, see SpyrosSakellariadis, "Migrating MS Mail to Exchange," April 1996.)

The Internet Mail connector links Exchange with the Internet and anySMTP-based system. This connector lets you send and receive Internet email fromExchange. Soon Microsoft and third-party vendors will introduce several gatewaysto provide access to SNADS and other data stores.