Reincarnating PC with portable SoulPads

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Reincarnating PC with portable SoulPads

• 2006. 11.15
• Nam, E Hyun

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Contents

• Introduction
• Architecture
• Implementation
• Experimental Results
• Discussion and Future work
• Conclusion

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Introduction

• Pros and Cons of Todays laptop system
• Pros
• Suspend and resume a session
• Personal and familiar SW environment
• Cons
• Relatively bulky device
• Limited capability of the HW
• Existing method for suspending/resuming a session
• Process migration
• GUI migration
• ISR

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Introduction

• SoulPads
• Components
• Portable storage device
• Fast local wired connections
• Auto-configuring OS
• Virtual Machine
• Widely deployed PC ecosystem
• Approaching method
• Decoupling the machine into a body and a soul
• Body display, CPU, RAM, I/O
• Soul session state, SW, data, preferences

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Introduction

• Pros and Cons of SoulPads
• Pros
• Battery
• Network connectivity
• Preloaded SW
• Availability of the full capabilities of the
  EnviroPC
• General benefits of virtualization
• Small and light weighted
• Suitable to developing country
• Cons
• Performance degradation
• Susceptible to loss or damage

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Contents

• Introduction
• Architecture
• Implementation
• Experimental Results
• Discussion and Future work
• Conclusion

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Architecture - Component

• A Host OS
• Boots on EnviroPCs
• Auto-configuration
• VMM
• Suspend/resume VMs
• Supports Guest OS diversity
• VM
• Runs the users Application on a Guest OS

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Architecture

• Design Issue
• Performance
• VM overhead, external disk
• Security and Privacy
• Vulnerability of a portable device
• Trustworthy of the SW on EnviroPCs
• Reliability
• Needs backup
• Hardware Independence
• Determine how wide a range of PCs SoulPads will
  operate

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Contents

• Introduction
• Architecture
• Implementation
• Experimental Results
• Discussion and Future work
• Conclusion

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Implementation

• Overview
• HW
• Off the shelf USB2.0 portable disks
• SW
• Auto-configuring Host OS Knoppix
• VMM Vmware
• Guest OS Windows or Linux

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Implementation

• Knoppix for the auto-configuring Host OS
• A version of GNU/linux distributed as a single
  bootable CD
• Auto configuration
• Initial RAM disk ( In- memory file system)
• Modification for SoulPad
• Installing Knoppix and bootloader on a USB hard
  disk
• Initial ramdisk and startup script
• Pros
• convenience
• Cons
• lose interest, limited to one OS

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Implementation

• Vmware workstation on top of Knoppix
• Guest OS diversity
• Suspend and Resume of user sessions
• VM suspended state and disk partition are saved
  as file
• SoulPad Use 4G partition to hold Knoppix and a 2G
  partition to serve as swap space remaining disk
  space is available for sharing among VM images

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Implementation
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Implementation

• Encrypted VM image
• Using AES128 block ciphor algorithm
• Loop-aes package of linux
• AES key retain in kernel memory
• Swap partition is also encrypted

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Implementation

• Network configuration
• From a networking perspective , a SoulPads
  suspend followed by a resume is similar to
  suspending a laptop at one location and resuming
  it at another location
• Backups
• TSM( Tivoli Storage Manager)
• File level network backup service
• Incremental backups both at the Host OS and Guest
  OS levels
• Suspended VM state at suspend time would not be
  backuped

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Contents

• Introduction
• Architecture
• Implementation
• Experimental Results
• Discussion and Future work
• Conclusion

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Experimental Result

• Characteristics of disks used
• Transfer rate measurement
• hdparm t
• Category of tests
• Suspend/resume latency
• Application response times
• Hardware independence

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Experimental Result Resume and suspend latencies
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Experimental Result Resume and suspend latencies

• Autoconfig VM state LoadResume is a major
  factor
• Ballooning can be used to reduce the latency of
  VM load
• Streamlining the Knoppix autoconfiguration could
  reduce the resume latency( remove the rebuilding
  procedure )
• .

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Experimental Result Resume and suspend latencies

• Compare SoulPad suspend/resume times to
  hibernate/resume and shutdown/boot times on
  Laptop

• Extra resume time is the price to pay for the
  added portability and hardware independence of
  SoulPad

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Experimental Result Application response times

• Used SYSmark 2002, an industry-standard benchmark
  suite

• NetVista PC with 1 GB physical mem and 512MB VM
  memory
• Usability

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Experimental Result Hardware independence

• How wide a range of PCs will SoulPad work?
• USB boot problem
• Cant resume a user session with the same
  graphics configuration( 1600X1200 V.S 1024 X 768)
• PC did not have enough memory
• Solution
• Creating mini-CD containing a boot loader that
  switches the boot sequence to a USB devices
• Sometimes necessary to manually change graphics
  setting after resume operation
• VMM should be able to swap portion of VM

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Contents

• Introduction
• Architecture
• Implementation
• Experimental Results
• Discussion and Future work
• Conclusion

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Discussion and future workISA diversity

• Situation
• VM permit guest OS to query the HW, determine the
  supported instructions and directly execute the
  available instruction
• If Guest OS move from P4 to P3
• Solutions
• Configure for an older processor family
• Multiple copies of ISA dependent component of
  Host OS
• ISA specific code path in Performance critical
  section
• Guest OS bind to the ISA at start time instead of
  install time
• Instruction Emulation

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Discussion and future work

• SW licensing
• Definition of a computer is unclear with
  virtualization SoulPad style mobility adds
  another twist
• Virtual V.S physical
• Processor V.S Storage
• VM dont hide all aspects of physical hardware
  from Guest OS ? SW installed on a Soulpads may
  stop working when moved between significantly
  different machines
• Vendor recognize the above issues and devise
  license terms that accommodate user needs

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Discussion and future work

• Developing countries
• It can work on disconnected PCs
• Support personalized computing on shared PCs
• Relatively low price
• Security and privacy
• We start EnviroPCs from a known power-down state
• We do not run any software previously installed
  on EnviroPCs
• We encrypt the VM image
• We do not write anything to storage in EnviroPCs
• We power down EnviroPC when SoulPad ends

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Comparison of mobility approaches
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Contents

• Introduction
• Architecture
• Implementation
• Experimental Results
• Discussion and Future work
• Conclusion

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Conclusion

• Key insight
• Large capacity USB 2.0 storage Autoconfiguring
  OS VMM, enables a new form of mobile computing
  environment
• Personal Opinion
• Auto configuration overhead may be reduced or
  eliminated by using appropriate caching method
• If we can easily use NAND flash based SSD( Solid
  state disk ), S/R performance may be improved
• If more faster, hot-pluggable Interface were to
  generalized, S/R performance might be improved.