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Reincarnating PC with portable SoulPads. 2006. 11.15 Nam, E Hyun. Contents. Introduction Architecture Implementation Experimental Results Discussion and Future work Conclusion. Introduction . Pros and Cons of Today’s laptop system Pros Suspend and resume a session
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Reincarnating PC with portable SoulPads 2006. 11.15 Nam, E Hyun
Contents • Introduction • Architecture • Implementation • Experimental Results • Discussion and Future work • Conclusion
Introduction • Pros and Cons of Today’s 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
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
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
Contents • Introduction • Architecture • Implementation • Experimental Results • Discussion and Future work • Conclusion
Architecture - Component • A Host OS • Boots on EnviroPCs • Auto-configuration • VMM • Suspend/resume VMs • Supports Guest OS diversity • VM • Runs the user’s Application on a Guest OS
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
Contents • Introduction • Architecture • Implementation • Experimental Results • Discussion and Future work • Conclusion
Implementation • Overview • HW • Off the shelf USB2.0 portable disks • SW • Auto-configuring Host OS : Knoppix • VMM : Vmware • Guest OS : Windows or Linux
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
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
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
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
Contents • Introduction • Architecture • Implementation • Experimental Results • Discussion and Future work • Conclusion
Experimental Result • Characteristics of disks used • Transfer rate measurement • hdparm –t • Category of tests • Suspend/resume latency • Application response times • Hardware independence
Experimental Result Resume and suspend latencies • Autoconfig & VM state Load+Resume 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 ) • .
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
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
Experimental Result Hardware independence • How widea range of PCs will SoulPad work? • USB boot problem • Can’t 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
Contents • Introduction • Architecture • Implementation • Experimental Results • Discussion and Future work • Conclusion
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
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 don’t 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
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
Contents • Introduction • Architecture • Implementation • Experimental Results • Discussion and Future work • Conclusion
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.