http://blog.csdn.net/shuiii/archive/2007/04/27/1587330.aspx--------------作者比较厉害，SD卡等都有涉及

注册表永久保存终于是搞定了，但新的问题又来了。由于注册表保存在nandflash，每次修改注册表都会去读写nandflash,播放视频时，对会写入很多新的注册表键值，每次读写nandflash来保存这些键值会造成很多ＣＰＵ资源的浪费，所以每次刚开始播放都会有停顿的现象。

解决：修改注册表platform.reg

[HKEY_LOCAL_MACHINE/init/BootVars]
   "SystemHive"="system.hv"
  "DefaultUser"="default"
  "Flags"=dword:3
  "RegistryFlags"=dword:1

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"RegistryFlags"=dword:1改成dword:0，不用每次注册表修改就自动去flush注册表。

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设置环境变量 　SET  PRJ_ENABLE_REGFLUSH_THREAD=1

IF PRJ_ENABLE_REGFLUSH_THREAD
[HKEY_LOCAL_MACHINE/System/ObjectStore/RegFlush]
; To monitor the flushing from an external process add "ActivityName" registry value.
; The activity name is a global named event that filesystem will signal on Registry Activity.
;   "ActivityName"=""
; Create an thread in filesys to perform flushing
    "SpawnThread"=dword:1
; Make the thread IDLE priority
    "FlushPriority256"=dword:FF
; ActivityThreshold specifies the # of reg activity before we force a flush
    "ActivityThreshold"=dword:100
; Timeout period for a flush (flush occurs if there have been some changes during this period)
    "FlushPeriod"=dword:3E8
ENDIF

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让系统在一个周期内都flush注册表。"FlushPeriod"=dword:3E8　默认设置为1秒钟。