The Design,
Implementation &
Evaluation of Cells : A
Virtual Smartphone
Architecture
By :
Versha Thakur
Shravani Aishwarya
Introduction


Smartphones- most necessary tools to carry nowadays.
Cells are used to enable virtual smartphone features.

Features like 3D graphics, power management, caller ID support etc.

Malicious software's can easily access data.

Solution – Virtual Machine (VM) Mechanism

Cells uses OS virtualization (run multiple VP’s on a single instance)

Tested on Google Nexus 1 and Nexus S phones.
Requirements

Support exclusive & shared access across VPs.

Sensitive information must never be leaked.

Prevent malicious applications.
USAGE MODEL

Cells runs on multiple VPs on a single hardware phone.

VP runs a standard Android environment.

Different level of access & permissions based on the function to be performed.

Switching of VPs depend on the level of access given.

VPs configured on a PC & downloaded to a phone via USB.
SYSTEM ARCHITECTURE

Kernel –Level Device
Virtualization
User- Level Device
Virtualization
Scalability Techniques
•
Introduces New kernel- level mechanisms
•
Device namespaces
•
Introduces user- level device namespace proxy
mechanism.
• Starting new VP, cell mounts the VP file system.
•
Cells enable Linux Kernel Samepage Merging
(KSM) for short time.
• Uses Android low memory killer – to increase total
no. of VPs.
GRAPHICS
Framebuffer
• Leverages Kernellevel device
namespace
• Driver (mux_fb)
• Multiplexes access to
a single physical
device.
GPU
• Replace Poor
quality graphics
• Scenes in a video
game, custom
animations.
Power
Management
• Background VPs
should not be able
to put the device
into a low power
mode.
• Should not
prevent the
foreground VP
from putting the
device into a low
power mode.
Experimental Results
REPEATABILITY

Resources are not expensive or difficult to perform research

Requires a group of people with knowledge of many different topics.

REPEATABLE, if proper knowledge in all fields of software & hardware.
EXTENDABILITY

Done in 2012.

Android latest version (4.3) supports the user profiles.

Samsung released few devices – one click switch between Android &
Windows.


Samsung is running two completely different OS on one device.
So research is already extended.
CRITICISM

Missing concepts such as Hardware virtualizations.

Latest cell phones are providing various multi-tasking features.

Only performed to run same OS on different VP’s.

If two different OS’s is implemented – increase the acceptance of the product.

Research on only one phone model Google Nexus.
CONCLUSION

Driven by virtualization mechanisms, device namespaces.

Virtualized critical hardware devices such as framebuffer and GPU.

Android’s complicated power management framework- no extra power
consumption.

Cells provides each VP with complete use of standard cellular phone network
by using VoIP cloud service.

Implemented on Google Nexus 1 and Nexus S.
REFERENCES

http://dl.acm.org/citation.cfm?id=2324876.2324877&coll=DL&dl=ACM

http://www.cs.columbia.edu/~cdall/pubs/Cells-SOSP-final.pdf

http://systems.cs.columbia.edu/projects/cells/

http://thecsbox.com/2013/05/cells-virtual-smartphone-architecture/

http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.231.5887