David Chappell


Get the Feed! Subscribe

On Defining "Workflow"  
# Saturday, May 20, 2006
If you're interested in business process management, and you're not reading every word that Bruce Silver writes, you need to start right now. Bruce is the best independent analyst I know of on BPM technology. Much of his work is available for free, too, including his excellent 2006 BPMS Report.

I read Bruce's recent blog entry on the use of the terms "workflow" and "BPM" with interest. He references a post by Keith Swenson, architect of Fujitsu's BPM product and a long-time participant in the Workflow Management Coalition. Both Bruce and Keith have roots in the traditional workflow world, where the term referred to automating interactions among people. Keith points out that he is heartened by Microsoft's use of the word "workflow" in the forthcoming Windows Workflow Foundation. He also proposes differentiating between workflow, meaning automation focused on human capabilities, and orchestration, meaning automation focused on system capabilities. BPM then becomes the umbrella category for both.

I like this distinction--it makes a lot of sense. Unfortunately, it doesn't match the way Microsoft is using the term "workflow". Windows Workflow Foundation will be used for automating human interactions, as in the workflow support being added to Windows SharePoint Services, Version 3 and Office SharePoint Server 2007. But it will also eventually be used for automating system interactions when it one day provides the orchestration capabilities in BizTalk Server. For Microsoft, the term"workflow" covers both areas.

What Microsoft has begun to do is distinguish between human workflow, as in Windows SharePoint Services, Version 3, and system workflow, as in a future version of BizTalk Server. Windows Workflow Foundation is meant to support both equally well, as well as allowing developers to create applications that span both areas. And because this technology will become a standard part of the Windows operating system, it's fair to expect Microsoft's preferred usage to become dominant in the half of the software world that uses .NET. Whatever one might wish, the naming conventions chosen by the big vendors have a disproportionate impact on the terminology we use.

5 comments :: Post a Comment



David, thanks for the kind words. You can find my post on BPM and workflow here. But I have one small correction to your post. Back in the 1990s in my "workflow roots" as you describe them, "workflow" did not mean human tasks only, but encompassed, as Microsoft's terminology does now, both human workflow and system workflow. The technology typically wasn't used for pure application integration but you can probably find some old Staffware (Tibco) and Pega installations that were pure straight-through processing. It's really since the merging of workflow and EAI traditions into BPM that the term workflow has come to signify human task management.

+1. But I also think we need a distinction between Orchestration between app domains and "inversion-of-control" frameworks that run within an app domain (which I write about in a 27 July post).

Although you can coerce the Microsoft offerings into either category, I put BizTalk in the first and Workflow Foundation in the latter.

Your entry is interesting, Erik, but I don't think your distinctions will hold up. Microsoft calls (or will relatively soon call) all of the things you describe "workflow".

And what happens when the orchestration function in BizTalk Server is replaced with one based on Windows Workflow Foundation, something Microsoft tells us will happen in the product's next major release?

Also, WF includes functions to support both system workflow (aka orchestration) and human workflow (including things such as the ability to change a running workflow on the fly). While I think your three categories have some historical validity, I don't believe they accurately describe the world we're heading into.

WF has no human workflow features per se. The Office Team is adding human workflow to Office 12, using -- in part -- the WF class library. BizTalk is only replacing their existing logic routing engine with WF. The ports, transforms, and process definitions are not necessarily affected by WF.

Maybe my distinctions are too architectural, but what should we call other apps, generally, that use WF (or the like) as their basis for execution? The fact that WF stands on it's own away from human workflow and orchestration tells me a distinction exists. But the work "workflow" is getting too overloaded, IMO.

"Workflow" certainly is an overloaded term. At least in the Microsoft half of the world, however, I don't think there's much choice except to adopt their terminology. In the context of WF, workflow becomes a quite technical thing, referring primarily to the ability of a workflow engine to execute activities.

As my post suggested, Microsoft then distinguishes between system workflow, where this core workflow engine is used to connect various different systems, as (one day) in BizTalk, and human workflow, where the same engine is used in scenarios that connect people. The system workflow case requires adapters, etc., as provided by BizTalk, while the human workflow case requires task lists, forms, and more, as provided by Windows SharePoint Services v3 and Office SharePoint Server 2007. At the heart of both, though, will eventually be the same technology: WF.

From this perspective, "workflow" describes a core technology, while "system workflow" and "human workflow" describe different ways that technology might be used, each with its own additional features.

So what about, say, a Windows Forms app that's driven by WF, or an ASP.NET application that uses WF to control its page flow? To me, those don't seem to fit into either the system workflow or human workflow buckets. I just call them "workflow-driven apps".

WF makes workflow (in the narrow technical sense) a core technology for creating pretty much any kind of application. Once everybody understands this and stops thinking solely of BizTalk or human workflow, I think things will be clearer.

Post a Comment

<< Home