Friday, February 22, 2008

Software + Services

This week I visited Microsoft campus in Reading, to hear some presentations on their Software-and-Service (S+S) strategy, and have a chat with Gianpaolo Carraro.

Phil Wainewright recently described Microsoft's S+S strategy as bunkum, and accused Gianpaolo of drinking too much Kool-Aid. Phil's point was that people didn't want to worry about buying software AND buying services.

However, Gianpaolo isn't really focusing on the commercial side of the equation. He spends most of his time talking about deployment. From this viewpoint, it makes sense in many situations to have a combination of stuff running on your own machines (called "software") and stuff running on other people's machines (called "services"). Actually that's what most users have anyway - both corporate users and domestic consumers.

But isn't it all software anyway? And who cares where the stuff is being run? Perhaps all of the people care some of the time, and some of the people care all of the time. I care when it affects my service level. For example, there are some places where broadband is unavailable, or at least very expensive. So if I want to work on an aeroplane, I may need to make sure the relevant documents are physically loaded onto my laptop beforehand.

The original vision of open distributed processing (ODP) included not only location transparency but other forms of transparency including migration and relocation. This means I don't notice when stuff moves around. Suppose I'm working on a bunch of documents that are currently on the server. Imagine my laptop knows my travel plans, knows that I'm going to be on an airplane this afternoon, works out which documents I'm going to need, and quietly and efficiently moves them while I'm in mid-edit, without dropping a comma.

I presume that Ray Ozzie, founder of Groove Networks and now Microsoft Chief Architect, understands these kind of requirements. He is pushing the S+S story hard.

But there is a conceptual problem with this semi-transparency - the fact that sometimes these aspects are visible and sometimes they aren't. ODP handles this by mandating several parallel viewpoints of a distributed system.

The CBDI method for service architecture and engineering (SAE) inherits this principle, although our viewpoints are not identical to the ODP ones. Meanwhile Microsoft has four perspectives, but these are defined in terms of process: Build, Run, Consume and Monetize.

When you want to think about deployment and location, you use one viewpoint; when you want to think about functionality and semantics, you use a different viewpoint; and when you want to think about commercial terms, costs and liabilities, you use a different one again.

I think this helps to explain the apparent disagreement between Gianpaolo and Phil. The S+S world looks very different from a commercial/organizational viewpoint and a deployment viewpoint. When I raised this with Gianpaolo, he made the valid point that these viewpoints cannot be totally isolated from one another. What happens from a deployment viewpoint inevitably has an impact upon the commercial viewpoint, and vice versa. Technological progress may help us reduce this impact, but it isn't going to disappear altogether any time soon.

But that doesn't mean the viewpoints simply merge into one unmanageable mess. The viewpoints are important precisely because they help us understand how things in one viewpoint relate to things in another viewpoint. And this in turn raises another important challenge. How are architects supposed to manage all this complexity? If you try to optimize the commercial/organizational arrangements alone, you may get unsatisfactory performance or service levels; if you try to optimize the physical deployment alone, you may not get the best commercial deal or organization structure; and if you try to optimize everything simultaneously, your head will explode. Gianpaolo's best advice at present is to do things at a very coarse level of granularity, which reduces the number of permutations to consider. But that's clearly not ideal.

The industry currently lacks decent tools to support this kind of architectural reasoning. We don't even have decent notations - you aren't going to get very far with colour-coded UML diagrams.

But what about enterprise SOA? Some people are working towards a world where all software is rendered as services - whether it is running on an enterprise server safely inside the firewall, or on a third-party server farm in Mumbai or Kiev. (By Day In Bollywood, By Night In The Ukraine.) Some of the same technical and conceptual issues here, but the terminology is different. S+S suggests that it only counts as a service if it is remote - this clashes with the enterprise SOA terminology.

Software-and-Services? The name may well generate some misunderstanding, especially if it is taken too literally, but that's probably true of any jargon. Not the name I'd have chosen, but then I'm not in charge of Microsoft's marketing strategy. Gianpaolo and his team have been working hard, producing some interesting material and examples, and the tools and techniques and future challenges coming out of this kind of work will undoubtedly be relevant to Enterprise SOA as well.


Gianpaolo Carraro: S+S: Real or have I drunk too much Kool-Aid? :)
Phil Wainewright: Microsoft Kool-Aid and the cloud
Gianpaolo Carraro: I think Phil drank the Kool-Aid too but he has not realized it yet :)
Ray Ozzie: MIX07 keynote, interview
Broadway Musical: "By day in Bollywood, by night in the Ukraine"
Reference Model for Open Distributed Processing (RM-ODP): Wikipedia, specification

No comments: