Difference between pages "Windows" and "SuperFetch"

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'''Windows''' is a widely-spread [[operating system]] from [[Microsoft]].
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SuperFetch is a performance enhancement introduced in [[Microsoft]] [[Windows|Windows Vista]] to reduce the time necessary to launch applications. SuperFetch works with the memory manager service in Windows to analyze memory usage patterns over time to determine the optimal memory content for a given user for a date or time of day. This differs from the [[Prefetch]] technique used in Microsoft Windows XP, which preloads data into memory without analyzing usage patterns.
  
There are 2 main branches of Windows:
+
From [http://msdn.microsoft.com/en-us/library/windows/hardware/dn653317(v=vs.85).aspx]: SuperFetch prioritizes the following kinds of pages to remain in memory:
* the DOS-branch: i.e. Windows 95, 98, ME
+
* Pages of applications that are used most frequently overall.  
* the NT-branch: i.e. Windows NT 4, XP, Vista
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* Pages of applications that are commonly used when resuming:  
 +
** After extensive hibernation (for example, first thing in the morning).
 +
** After shorter periods of sleep or hibernation (for example, after lunch).
  
== Features ==
+
If SuperFetch detects that the system drive is a fast SSD (as measured by Windows Experience Index Disk score), then SuperFetch turns off [[ReadyBoot]], [[ReadyBoost]], and the SuperFetch service itself.
* Basic and Dynamic Disks, see: [http://msdn.microsoft.com/en-us/library/windows/desktop/aa363785(v=vs.85).aspx]
+
  
=== Introduced in Windows NT ===  
+
== Components ==
* [[NTFS]]
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=== Robust performance ===
 +
Robust performance (or robustness) is a component of SuperFetch to watch for specific file I/O access that might harm system performance by populating the standby lists with unneeded data.
  
=== Introduced in Windows 2000 ===  
+
== Scenarios ==
 +
SuperFetch distinguishes between different scenarios to accurately measure performance.
  
=== Introduced in Windows XP ===
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=== Cold scenario ===
* [[Prefetch]]
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In a cold scenario, the test applications are not already in memory when the test begins. Cold scenarios measure performance either after a state transition, such as boot or resume from hibernation, or after another application claims most of the available memory, such as after launching and quitting a game.
* System Restore (Restore Points); also present in Windows ME
+
  
==== SP2 ====
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=== Warm scenario ===
* Windows Firewall
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In a warm scenario, some or all the scenario contents are in memory before measurement. This usually means that the test has run at least once during this logon session.
  
=== Introduced in Windows 2003 (Server) ===
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== Configuration ==
* Volume Shadow Copies
+
  
=== Introduced in Windows Vista ===
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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 [[Registry]] value [http://www.codinghorror.com/blog/archives/000688.html]:
* [[BitLocker Disk Encryption | BitLocker]]
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<pre>
* [[Windows Desktop Search | Search]] integrated in operating system
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Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters
* [[SuperFetch]]
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Value: EnableSuperfetch
* [[NTFS|Transactional NTFS (TxF)]]
+
</pre>
* [[Windows NT Registry File (REGF)|Transactional Registry (TxR)]]
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* [[Windows Shadow Volumes|Shadow Volumes]]; the volume-based storage of the Volume Shadow Copy data
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* $Recycle.Bin
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* [[Windows XML Event Log (EVTX)]]
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* [[User Account Control (UAC)]]
+
  
=== Introduced in Windows 2008 (Server) ===
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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/].
  
=== Introduced in Windows 7 ===
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== File Formats ==
* [[BitLocker Disk Encryption | BitLocker To Go]]
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* [[Jump Lists]]
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* [[Sticky Notes]]
+
  
=== Introduced in Windows 8 ===
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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. Note that there are likely more SuperFetch database files named differently, presumably all using the .db extension.
* [[Windows Shadow Volumes | File History]]
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* [[Windows Storage Spaces | Storage Spaces]]
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* [[Resilient File System (ReFS)]]; server edition will likely be available in Windows Server 2012
+
  
== Forensics ==
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The format of the SuperFetch database 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/]. For more information see [[Windows SuperFetch Format|SuperFetch Format]].
  
=== Partition layout ===
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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].
Default partition layout, first partition starts:
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* at sector 63 in Windows 2000, XP, 2003
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* at sector 2048 in Windows Vista, 2008, 7
+
  
=== Filesystems ===
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The SuperFetch service is managed by the File Information FS MiniFilter service. It appears that most of the SuperFetch database files are updated (written) when the service is shut down. AgAppLaunch.db is also written when the service starts.
* [[FAT]], [[FAT|exFAT]]
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* [[NTFS]]
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* [[Resilient File System (ReFS) | ReFS]]
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=== Recycle Bin ===
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+
==== RECYCLER ====
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Used by Windows 2000, XP.
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Uses INFO2 file.
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See: [http://www.cybersecurityinstitute.biz/downloads/INFO2.pdf]
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==== $RECYCLE.BIN ====
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Used by Windows Vista.
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Uses $I and $R files.
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See: [http://www.forensicfocus.com/downloads/forensic-analysis-vista-recycle-bin.pdf]
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=== Registry ===
+
 
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The [[Windows Registry]] is a database of keys and values that provides a wealth of information to forensic [[investigator]]s.
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=== Thumbs.db Files ===
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[[Thumbs.db]] files can be found on many Windows systems. They contain thumbnails of images or documents and can be of great value for the [[investigator]].
+
 
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See also: [[Vista thumbcache]].
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=== Browser Cache ===
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=== Browser History ===
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The [[Web Browser History]] files can contain significant information. The default [[Web browser|web browser]] that comes with Windows is [[Internet Explorer|Microsoft Internet Explorer]] but other common browsers on Windows are [[Apple Safari]], [[Google Chrome]], [[Mozilla Firefox]] and [[Opera]].
+
 
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=== Search ===
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See [[Windows Desktop Search]]
+
 
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=== Setup log files (setupapi.log) ===
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Windows Vista introduced several setup log files [http://support.microsoft.com/kb/927521].
+
 
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=== Sleep/Hibernation ===
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After (at least) Windows 7 recovers from sleep/hibernation there often is a system time change event (event id 1) in the event logs.
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=== Users ===
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Windows stores a users Security identifiers (SIDs) under the following registry key:
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<pre>
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HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList
+
</pre>
+
 
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The %SID%\ProfileImagePath value should also contain the username.
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== Advanced Format (4KB Sector) Hard Drives ==
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Windows XP does not natively handle drives that use the new standard of 4KB sectors. For information on this, see [[Advanced Format]].
+
 
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== %SystemRoot% ==
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The actual value of %SystemRoot% is store in the following registry value:
+
<pre>
+
Key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\
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Value: SystemRoot
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</pre>
+
  
 
== See Also ==
 
== See Also ==
* [[Windows Event Log (EVT)]]
+
* [[Prefetch]]
* [[Windows XML Event Log (EVTX)]]
+
* [[ReadyBoost]]
 +
* [[ReadyBoot]]
 +
* [[Windows SuperFetch Format|SuperFetch Format]]
 +
* [[Windows]]
  
 
== External Links ==
 
== External Links ==
 +
* [http://technet.microsoft.com/en-us/magazine/2007.03.vistakernel.aspx Inside the Windows Vista Kernel: Part 2], by [[Mark Russinovich]], March 2007
 +
* [http://download.microsoft.com/download/7/E/7/7E7662CF-CBEA-470B-A97E-CE7CE0D98DC2/Win7Perf.docx Performance Testing Guide for Windows], by [[Microsoft]], August 18, 2009 
 +
* [http://en.wikipedia.org/wiki/Windows_Vista_I/O_technologies#SuperFetch Wikipedia: Windows Vista I/O technologies - SuperFetch]
 +
* [http://channel9.msdn.com/showpost.aspx?postid=242429 Channel 9 Interview with Michael Fortin of Microsoft on SuperFetch]
 +
* [http://www.informationweek.com/news/showArticle.jhtml?articleID=196902178 Microsoft Predicts The Future With Vista's SuperFetch] from Information Week
 +
* [http://jessekornblum.com/presentations/dodcc08-2.pdf DC3 Presentation: My You Look SuperFetching], by Jesse Kornblum
  
* [http://en.wikipedia.org/wiki/Microsoft_Windows Wikipedia: Microsoft Windows]
+
== Tools ==
* [http://support.microsoft.com/kb/927521 Windows 7, Windows Server 2008 R2, and Windows Vista setup log file locations]
+
=== Open Source ===
* [http://www.forensicfocus.com/downloads/forensic-analysis-vista-recycle-bin.pdf The Forensic Analysis of the Microsoft Windows Vista Recycle Bin], by [[Mitchell Machor]], 2008
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* [https://code.google.com/p/rewolf-superfetch-dumper/ rewolf-superfetch-dumper]
* [http://www.ericjhuber.com/2013/02/microsoft-file-system-tunneling.html?m=1 Microsoft Windows File System Tunneling], by [[Eric Huber]], February 24, 2013
+
 
+
=== Under the hood ===
+
* [http://msdn.microsoft.com/en-us/library/windows/desktop/aa366533(v=vs.85).aspx MSDN: Comparing Memory Allocation Methods], by [[Microsoft]]
+
* [http://blogs.msdn.com/b/ntdebugging/archive/2007/06/28/how-windows-starts-up-part-the-second.aspx How Windows Starts Up (Part the second)]
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* [http://msdn.microsoft.com/en-us/library/aa375142.aspx DLL/COM Redirection]
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* [http://msdn.microsoft.com/en-us/library/windows/desktop/ms682586(v=vs.85).aspx Dynamic-Link Library Search Order]
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* [http://blogs.msdn.com/b/junfeng/archive/2004/04/28/121871.aspx Image File Execution Options]
+
 
+
=== Side-by-side (WinSxS) ===
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* [http://en.wikipedia.org/wiki/Side-by-side_assembly Wikipedia: Side-by-side assembly]
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* [http://msdn.microsoft.com/en-us/library/aa374224.aspx Assembly Searching Sequence]
+
* [http://blogs.msdn.com/b/junfeng/archive/2007/06/26/rt-manifest-resource-and-isolation-aware-enabled.aspx RT_MANIFEST resource, and ISOLATION_AWARE_ENABLED]
+
* [http://msdn.microsoft.com/en-us/library/windows/desktop/dd408052(v=vs.85).aspx Isolated Applications and Side-by-side Assemblies]
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* [http://blogs.msdn.com/b/junfeng/archive/2006/01/24/517221.aspx#531208 DotLocal (.local) Dll Redirection], by [[Junfeng Zhang]], January 24, 2006
+
* [http://blogs.msdn.com/b/junfeng/archive/2006/04/14/576314.aspx Diagnosing SideBySide failures], by [[Junfeng Zhang]], April 14, 2006
+
* [http://omnicognate.wordpress.com/2009/10/05/winsxs/ EVERYTHING YOU NEVER WANTED TO KNOW ABOUT WINSXS]
+
 
+
=== Application Compatibility Database ===
+
* [http://technet.microsoft.com/en-us/library/dd837644(v=ws.10).aspx Technet: Understanding Shims], by [[Microsoft]]
+
* [http://msdn.microsoft.com/en-us/library/bb432182(v=vs.85).aspx MSDN: Application Compatibility Database], by [[Microsoft]]
+
* [http://www.alex-ionescu.com/?p=39 Secrets of the Application Compatilibity Database (SDB) – Part 1], by [[Alex Ionescu]], May 20, 2007
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* [http://www.alex-ionescu.com/?p=40 Secrets of the Application Compatilibity Database (SDB) – Part 2], by [[Alex Ionescu]], May 21, 2007
+
* [http://fred.mandiant.com/Whitepaper_ShimCacheParser.pdf Leveraging the Application Compatibility Cache in Forensic Investigations], by [[Andrew Davis]], May 4, 2012
+
 
+
=== System Restore (Restore Points) ===
+
* [http://en.wikipedia.org/wiki/System_Restore Wikipedia: System Restore]
+
* [http://www.stevebunting.org/udpd4n6/forensics/restorepoints.htm Restore Point Forensics], by [[Steve Bunting]]
+
* [http://windowsir.blogspot.ch/2007/06/restore-point-analysis.html Restore Point Analysis], by [[Harlan Carvey]],  June 16, 2007
+
* [http://windowsir.blogspot.ch/2006/10/restore-point-forensics.html Restore Point Forensics], by [[Harlan Carvey]], October 20, 2006
+
* [http://www.ediscovery.co.nz/wip/srp.html System Restore Point Log Decoding]
+
 
+
=== Windows Firewall ===
+
* [http://en.wikipedia.org/wiki/Windows_Firewall Wikipedia: Windows Firewall]
+
* [http://technet.microsoft.com/en-us/library/cc737845(v=ws.10).aspx#BKMK_log Windows Firewall Tools and Settings]
+
 
+
=== Windows 32-bit on Windows 64-bit (WoW64) ===
+
* [http://en.wikipedia.org/wiki/WoW64 Wikipedia: WoW64]
+
 
+
=== Windows XP ===
+
* [http://support.microsoft.com/kb/q308549 Description of Windows XP System Information (Msinfo32.exe) Tool]
+
 
+
=== Windows 8 ===
+
* [http://en.wikipedia.org/wiki/Features_new_to_Windows_8 Features new to Windows 8], Wikipedia
+
* [http://computerforensics.champlain.edu/blog/windows-8-forensics Windows 8 Forensics - part 1]
+
* [http://computerforensics.champlain.edu/blog/windows-8-forensics-part-2 Windows 8 Forensics - part 2]
+
* [http://computerforensics.champlain.edu/blog/windows-8-forensics-part-3 Windows 8 Forensics - part 3]
+
* [http://propellerheadforensics.files.wordpress.com/2012/05/thomson_windows-8-forensic-guide2.pdf Windows 8 Forensic Guide], by [[Amanda Thomson|Amanda C. F. Thomson]], 2012
+
* [http://forensicfocus.com/Forums/viewtopic/t=9604/ Forensic Focus: Windows 8 Forensics - A First Look], [http://www.youtube.com/watch?v=uhCooEz9FQs&feature=youtu.be Presentation], [http://www.forensicfocus.com/downloads/windows-8-forensics-josh-brunty.pdf Slides], by [[Josh Brunty]], August 2012
+
* [http://dfstream.blogspot.ch/2013/03/windows-8-tracking-opened-photos.html Windows 8: Tracking Opened Photos], by [[Jason Hale]], March 8, 2013
+
  
[[Category:Operating systems]]
+
[[Category:Windows]]

Revision as of 07:10, 28 June 2014

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. SuperFetch works with the memory manager service in Windows to analyze memory usage patterns over time to determine the optimal memory content for a given user for a date or time of day. This differs from the Prefetch technique used in Microsoft Windows XP, which preloads data into memory without analyzing usage patterns.

From [1]: SuperFetch prioritizes the following kinds of pages to remain in memory:

  • Pages of applications that are used most frequently overall.
  • Pages of applications that are commonly used when resuming:
    • After extensive hibernation (for example, first thing in the morning).
    • After shorter periods of sleep or hibernation (for example, after lunch).

If SuperFetch detects that the system drive is a fast SSD (as measured by Windows Experience Index Disk score), then SuperFetch turns off ReadyBoot, ReadyBoost, and the SuperFetch service itself.

Components

Robust performance

Robust performance (or robustness) is a component of SuperFetch to watch for specific file I/O access that might harm system performance by populating the standby lists with unneeded data.

Scenarios

SuperFetch distinguishes between different scenarios to accurately measure performance.

Cold scenario

In a cold scenario, the test applications are not already in memory when the test begins. Cold scenarios measure performance either after a state transition, such as boot or resume from hibernation, or after another application claims most of the available memory, such as after launching and quitting a game.

Warm scenario

In a warm scenario, some or all the scenario contents are in memory before measurement. This usually means that the test has run at least once during this logon session.

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 Registry value [2]:

Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters
Value: EnableSuperfetch

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 [3].

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 [4]. These files appear to start with the prefix Ag and have a .db extension. Note that there are likely more SuperFetch database files named differently, presumably all using the .db extension.

The format of the SuperFetch database files is not fully known, there is available unofficial partial specification [5] and open source (GPL) dumper for .db files [6]. For more information see SuperFetch Format.

The SuperFetch feature is seeded with some basic usage patterns when the operating system is installed [7].

The SuperFetch service is managed by the File Information FS MiniFilter service. It appears that most of the SuperFetch database files are updated (written) when the service is shut down. AgAppLaunch.db is also written when the service starts.

See Also

External Links

Tools

Open Source