Thursday, December 4, 2008

SAAS or SAS? that's the question!

Abbreviations are a common thing in IT.
But these abbreviations can lead to possible ambiguities.

This is the case when SAS (Software As Service) and SAAS (Software As A Service) are used.These two software model delivery systems look alike regarding their name, but are still different in their software delivery.
SAS is a melting pot of SAAS and SOA, combining the software-functionality without owning it (SAAS) with the composability and division- approach from SOA, enabling a network of SAAS-vendors and -clients. This last characteristic is very important for a testprofessional like me.

SAAS can be seen as a one-to-one relationship between SAAS-vendor and SAAS-client (e.g. CRM Salesforce), whereas SAS is a network of vendors and clients using the functionality of SAS (e.g. Google Maps).
This makes testing of SAS more difficult than SAAS because there are more stakeholders and the system is more complex. However, very important for a tester, because SAS is where it is going to on the world wide web.

The testprofessional who is responsible for testing the whole SAS-chain has to find out who is involved in the SAS-process, what they want with the SAS-application , how the vendors build their part of the SAS-chain and how they tested it. Otherwise he can't perform his end- to end-test/ big bang test in his test-environment.
The chain to be tested contains different modules of SAS-vendors and SAS-clients, coupled by interfaces. This makes the work of the responsible tester complex because he has to know the functionality of each SAAS-module and the functionality of the interfaces between each SAAS-module. This also requires documentation (even in an agile environment)
A tester has to know the desired functionality ,otherwise he can't test.

Just a few thoughts on my view of the future of SAAS and SAS.
More will follow soon.
Feel free to share your thoughts about this with me.

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