History of OWA

Here is an interesting post by Jim Van Eaton on the history of OWA...

"The Exchange Web Client" was the first web email client produced by Microsoft.  It had an interesting green and black color scheme but it did most of the basic needs for doing messaging.  We didn't have enough time to add calendaring support in the first version.  What we did in this first version was the first step in what has now become a new way of building web applications.

OWA was born out of the sheer will of my friend Bob Gering when he decided we should look exactly like Outlook.  We started changing our frameset design, colors and graphics to look and feel like Outlook.  It was this desire to look, act and feel like Outlook that caused us to move web applications forward in a new evolutionary path.

Traditional web applications constantly refresh the document for just about every action. During Exchange 5.5 development in 1996/97 we used hidden frames to communicate to the server when sending messages so we wouldn't clear the user's document.  However, we still had many frames updating during navigation of the mailbox.  We also developed a Java applet for the date picker control in the calendar view to augment the user experience since DHTML on the current browsers at that time was just about non-existent.  In the end we found that the applet did not meet our performance needs because virtual machine initialization was too expensive. OWA 5.5 had richer support than prior versions but it still lacked the type of experience that users get in a win32 application but it did work on just about every browser under the sun.

In 1998 we started on the incredible task of rewriting OWA for Exchange 2000.  There were competing teams that were working on this task.  WebDav had a team, led by Russ Simpson, working on a very basic hotmail like experience.  The architecture of this version was the most interesting part.  It was scalable and fast because it was actually built into the Exchange store process.  Bob Gering, Ward Beattie, Iain McDonald and I were on the CDO (Collaboration Data Objects) team building a version with DHTML controls on an alpha version of IE5.  Management fixed the redundant effort issue and joined the two teams together with Ward leading the way.  It made perfect sense to combine the efforts of great plumbers along with great painters. 

Continued at source...