1. Mohsen Anvaari Slinger Jansen
Evaluating Architectural Openness
in Mobile Software Platforms
2nd Workshop on Software Ecoystems
Copenhagen – August 23th, 2010

2. 2
Agenda
 Subject and Problem Area
 Some Definitions
 Research Questions
 Research Scope
 Related Research
 Methodology
 Results
 Conclusions
 Questions

3. 3
Subject and Problem Area
 Openness in Software Systems and Projects
 Mobile Software Platforms
 Openness Strategy, Platform Architecture,
Platform Accessibility
Evaluating Architectural Openness in Mobile Software Platforms

4. 4
Some Definitions
 Openness: Degree of accessibility to view, use,
and modify a software code
 Openness strategy: Openness degree of a
platform settled by the platform supplier
 Platform architecture: Structure of the software
platform compromises its components and the
relationship between them (Bass et. al, 2003)
 Platform accessibility: Methods and points that
developers can use to extend or modify a
platform

5. 5
Research Questions
 RQ: How does the software architecture
expose the openness strategy of mobile
software platforms?
 SQ1: Can a model be developed that describes
the architectural openness of mobile platforms?
 SQ2: How would the licensing aspects of the
platforms relate to such a model?
 SQ3: How open are the five main mobile
platforms?

6. 6
Research Scope

7. Related Researches
 Few attempts have been made to demonstrate the
comparison of smartphone OSs (Lin and Ye, 2009)
 Lin and Ye, 2009: comparison of four main mobile
platforms and their openness, based on non-technical
aspects
 Cho and Joen, 2007: Openness and architecture of three
platforms, a connection is not included
 Yamakami, 2009: Comparison of four main mobile
platforms, based on non-technical aspects
7

8. 8
Methodology
 Literature review: Finding the relationship
between openness strategies and the software
architecture of mobile platforms
 Qualitative interviews with mobile
application developers: Verify the platform
accessibility in the five main platforms that allows
application developers to extend the platforms

9. 9
Results
 Architectural Openness Model
 Architectural Openness Factors
 Openness in Five Main Mobile Platforms

10. 10
Results: Architectural Openness Model
Applications
Middleware
Kernel
Extended ApplicationsNative Applications
App 1 App 2 App 3 App N...
(Services, Libraries, Frameworks …)
(Device Drivers, Memory Management, Power Management, Security …)
App 1 App 2 App 3 App M...
Platform Architecture
Symbian Architecture Android Architecture
+
Platform Accessibility
Integrate
Extend
Modify
Integrate
Extend
Modify
Integrate
Extend
Modify
Integrate
Extend
Modify
Architecture (Cho and Jeon, 2007) iPhone Architecture

11. Results: Architectural Openness Factors
Layer Factor
Possibility
statuses
If possibleLicensing
statuses
Extended applications
Integrate extended
applications
Possible/
Possible for
some
components/
Not possible
Permission is not
needed/ In some
situation
permission is
needed/ Permission
is always needed
Extend extended applications
Modify extended applications
Native applications
Integrate native applications
Extend native applications
Modify extended applications
Middleware
Integrate middleware
Extend middleware
Modify middleware
Kernel
Integrate kernel
Extend kernel
Modify kernel

12. Comparison
Factor Android Symbian Windows Mobile Blackberry iPhone
P L P L P L P L P L
Integrate extended
applications
Extend extended
applications
Modify extended
applications
Integrate native
applications
Extend native
applications
Modify native
applications
Integrate
middleware
Extend middleware
Modify middleware
Integrate kernel
Extend kernel
Modify kernel
P - Possibility: Possible (G), Possible for Some Components (Y), Not Possible (Red)
L - Licensing: Permission is Not Needed(G), Sometimes Permission is Needed(Yellow),
Permission is Always Needed(R)

13. 13
Conclusions
 Proposed architectural openness model shows how the
openness strategies of mobile platform suppliers affect
the software architecture of the platforms
 Proposed architectural openness factors shows how
open the mobile software platforms are
 Based on the model and the factors, the openness
degree of five main mobile platforms is indentified
 Qualitative interviews validate the previous conclusion
 Interviews show application developers don’t care about
architectural openness of their favorite platforms
 Interview with Some Device Manufacturers, and Mobile
Suppliers is recommended

14. 14
Questions