Difference between pages "JTAG Samsung Galaxy Centura (SCH-S738C)" and "SuperFetch"

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== Samsung Galaxy Centura SCH-S738C ==
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{{Expand}}
  
This phone is supported by the Tracfone network and uses a Qualcomm MSM7625A 800 MHz Snapdragon (S1) Processor. The phone has 4 GB of internal storage with a Samsung KMSJS000KM B308 MoviNAND flash memory chip. This phone is unsupported by RIFF Box for the JTAG process but can be imaged with the direct access plugin.  
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SuperFetch is a performance enhancement introduced in [[Microsoft]] [[Windows|Windows Vista]] to reduce the time necessary to launch applications. An expanded version of the [[Prefetch]] files found in Windows XP, they record usage scenarios and load resources into memory before they are needed. Those resources can be loaded into physical memory and extra memory provided by [[ReadyBoost]].
  
{| border="1" cellpadding="2"
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== Configuration ==
|-
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| [[ File:S738C_front.JPG | 300px ]]
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|-
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|}
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=== Getting Started ===
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Because SuperFetch appears to leave a system with no available memory, some users turn it off to create the appearance of having more free memory. The feature can be configured by changing the <tt>HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters\EnableSuperfetch</tt> [[Registry]] key [http://www.codinghorror.com/blog/archives/000688.html]. A value of zero disables SuperFetch, one enables it for booting only, two for applications, and three for both applications and boot. This setting can also be changed using the Services console, <tt>services.msc</tt> [http://tiredblogger.wordpress.com/2007/03/27/superfetch-not-so-super-for-gaming/].
  
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== File Formats ==
  
What you need:
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Data for SuperFetch is gathered by the <tt>%SystemRoot%\System32\Sysmain.dll</tt>, part of the Service Host process, <tt>%SystemRoot%\System32\Svchost.exe</tt>, and stored in a series of files in the <tt>%SystemRoot%\Prefetch</tt> directory [http://www.microsoft.com/technet/technetmag/issues/2007/03/VistaKernel/]. These files appear to start with the prefix <tt>Ag</tt> and have a <tt>.db</tt> extension. The format of these files is not fully known, there is available unofficial partial specification [http://blog.rewolf.pl/blog/?p=214] and open source (GPL) dumper for .db files [http://code.google.com/p/rewolf-superfetch-dumper/]. Some information can be gleaned from these files by searching for [[Unicode]] [[strings]] in them.
  
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The SuperFetch feature is seeded with some basic usage patterns when the operating system is installed [http://channel9.msdn.com/showpost.aspx?postid=242429].
  
# Riff Box
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== See Also ==
# USB to Micro USB cord
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* [[Prefetch]]
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* [[Windows]]
  
 
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== External Links ==
=== NAND Dump Procedure ===
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* [http://en.wikipedia.org/wiki/Windows_Vista_I/O_technologies#SuperFetch Wikipedia: Windows Vista I/O technologies - SuperFetch]
 
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* [http://channel9.msdn.com/showpost.aspx?postid=242429 Channel 9 Interview with Michael Fortin of Microsoft on SuperFetch]
 
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* [http://www.informationweek.com/news/showArticle.jhtml?articleID=196902178 Microsoft Predicts The Future With Vista's SuperFetch] from Information Week
# Remove the rear cover, exposing the 7 phillips head screws.
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* [http://jessekornblum.com/presentations/dodcc08-2.pdf DC3 Presentation: My You Look SuperFetching]
# Remove the screws and the rear plastic casing with a plastic pry tool.
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* [http://code.google.com/p/rewolf-superfetch-dumper/ Open source Ag*.db files dumper]
# Remove the two molex connectors attached on the right and top of the printed circuit board.
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* [http://blog.rewolf.pl/blog/?p=214 SuperFetch file format - partial specification]
# Remove the printed circuit board from the screen casing exposing the nine TAPS on the reverse side. Note the small copper carrot indicating the direction of the TAPS.
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# Connect the RIFF box to the JTAG pins.
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# Connect the PCB to a Micro USB cord and power via a power supply.
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# Start the "RIFF box" software.
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# Power the PCB.
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# Dump the NAND.
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{| border="1" cellpadding="2"
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|-
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| [[ File:S738C_back.JPG | 300px ]]
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|-
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|}
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{| border="1" cellpadding="2"
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|-
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| [[ File:S738C_case.JPG | 300px ]]
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|-
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|}
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{| border="1" cellpadding="2"
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|-
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| [[ File:S738C_molex.JPG | 300px ]]
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|-
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|}
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The TAPS order is as follows:
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# 1=GND
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# 2=NRST
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# 3=TDO
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# 4=TCK
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# 5=TDI
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# 6=TRST
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# 7=RTCK
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# 8=TMS
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# 9=N/A
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{| border="1" cellpadding="2"
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|-
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| [[ File:S738C_TAPS.JPG | 400px ]]
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|-
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|}
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***Test has shown for the best results and fewer read errors, use short wires directly to the RIFF box ribbon interface.***
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{| border="1" cellpadding="2"
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|-
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| [[ File:S738C_riff.JPG | 400px ]]
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|-
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|}
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After the wires are connected to the board, the phone is powered by the USB connection. Plug the Micro USB into the USB connection on the device and then plug the phone into the USB port on the laptop.
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Launch the Riff Box JTAG Manager and use the following settings:
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* Navigate to the Useful Plugins tab
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* Select the Direct JTAG Access to Flash Memory Plugin. Note the directions displayed in the window along with supported processors.
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* Activate the plugin
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* Choose the MSM7627A from the drop down menu on the right side ** Note this is not the processor but it will allow access the the memory.
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* Select eMMC SDC3 (via chipset) from the Memory Type & Host drop down.
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* Check Auto FullFlash size
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* Select Connect & Flash ID. ** This will not flash the memory chip initially, but will only connect**
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* Choose the read button from the bottom left corner. This will connect to the device and display the partitions and chip ID.
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{| border="1" cellpadding="2"
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|-
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| [[ File:active_plugin.JPG | 800px ]]
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|-
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|}
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{| border="1" cellpadding="2"
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|-
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| [[ File:SCH-S738C_Setting2.JPG | 800px ]]
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|-
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|}
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{| border="1" cellpadding="2"
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|-
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| [[ File:SCH_S738C_Setting2.PNG | 800px ]]
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|-
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|}
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=== Notes ===
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The phone has a 4GB MoviNAND flash memory chip which should take approximately 24 hours to download. This takes much longer the normal because the direct access plugin functions at a much slower speed then normal JTAG methods. Test have found using shorter large wires and no intermediate PCB board increases performance.
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=== References ===
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*http://www.riffbox.org/
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Revision as of 14:23, 30 December 2013

Information icon.png

Please help to improve this article by expanding it.
Further information might be found on the discussion page.

SuperFetch is a performance enhancement introduced in Microsoft Windows Vista to reduce the time necessary to launch applications. An expanded version of the Prefetch files found in Windows XP, they record usage scenarios and load resources into memory before they are needed. Those resources can be loaded into physical memory and extra memory provided by ReadyBoost.

Configuration

Because SuperFetch appears to leave a system with no available memory, some users turn it off to create the appearance of having more free memory. The feature can be configured by changing the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters\EnableSuperfetch Registry key [1]. A value of zero disables SuperFetch, one enables it for booting only, two for applications, and three for both applications and boot. This setting can also be changed using the Services console, services.msc [2].

File Formats

Data for SuperFetch is gathered by the %SystemRoot%\System32\Sysmain.dll, part of the Service Host process, %SystemRoot%\System32\Svchost.exe, and stored in a series of files in the %SystemRoot%\Prefetch directory [3]. These files appear to start with the prefix Ag and have a .db extension. The format of these files is not fully known, there is available unofficial partial specification [4] and open source (GPL) dumper for .db files [5]. Some information can be gleaned from these files by searching for Unicode strings in them.

The SuperFetch feature is seeded with some basic usage patterns when the operating system is installed [6].

See Also

External Links