Both David and Antony talk about the contract basis of the laundry model.
- I delegate something (in this case cleaning) to the laundry service.
- Officially I don't care how it's done (although the term "dry cleaning" seems to indicate a preferred implementation).
- The laundry service accepts some (limited) liability for any failure.
- I entrust the service with something (an asset) that belongs to me.
- I expect the laundryman to be discrete. I do not want my dirty linen washed in public - in other words, I do not expect the laundryman to draw any inferences from the state of my clothes, or to pass these inferences to inquisitive journalists.
- If something goes wrong with the service, then my asset is damaged. The potential liability is linked to the value of the asset, not to the value of the service. (If my dress suit is ruined, I am not going to be happy if I just get the cost of the cleaning reimbursed.)
- I do not authorize the service provider to use the asset for his own purposes. (I do not expect the laundryman to borrow my suit for his daughter's wedding.)
However, there are many services where this is not clearly agreed. Perhaps I get some cut-price service, and this is only economically viable because the service provider expects to be able to broadcast some advertising to me or my customers. But if I am careless with the small print on the contract, I may not have understood this aspect of the deal.
And there are many services where this simply doesn't apply. For example, information services often simply involve transferring information from the service provider to the consumer, while Software-as-a-Service may simply involve transferring functionality. Obviously there are trust issues here as well - I trust the BBC to provide accurate and balanced news, I trust my internet security provider to protect me from viruses, I trust Microsoft Excel to calculate my profits correctly - but these are not linked in quite the same way to specific assets.
So I think the laundry metaphor is a very useful one, but like any metaphor we must be careful not to push it too far. All services are a bit like laundry, and some services are very much like laundry, but few services are totally like laundry.
See also
Services Not All Like Laundry (July 2008)
Laundry as Intelligence (Oct 2008)
Understanding Business Services (November 2012)
Great article. I have mentioned yet another analogy using home construction that I have used successfully in the past.
ReplyDeletehttp://blogs.oracle.com/aia/2008/07/the_world_of_soa_laundries_leg.html
Hi Rajesh. Your example is a good one, raising lots of issues about the way different types of service (delivering materials, working on the materials, certifying that the work satisfies building regulations) must be orchestrated. How do the electricians and the plumbers and the painters avoid getting in one another's way - do they talk directly to one another, or only via the general contractor?
ReplyDeleteThanks for mentioning this post. For the sake of completeness, you might also want to look at the sequel Services Not All Like Laundry.
The post Explaining SOA to Business can be found at: http://tinyurl.com/dyz55jw
ReplyDelete