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Application Deployment 9 - 23

Flash Storage

In addition to the RAM-based storage standard on Windows CE mobile computers, the mobile computer is also
equipped with a non-volatile Flash-based storage area which can store data (partitions) that can not be corrupted
by a cold boot. This Flash area is divided into two categories: Flash File System (FFS) Partitions and Non-FFS
Partitions.

FFS Partitions

The mobile computer includes two FFS partitions. These partitions appear to the mobile computer as a hard drive
that the OS file system can write files to and read files from. Data is retained even if power is removed.

The two FFS partitions appear as two separate folders in the Windows CE file system and are as follows:

•

Platform: The Platform FFS partition contains Symbol-supplied programs and Dynamic Link Libraries (DLLs).
This FFS is configured to include DLLs that control system operation. Since these drivers are required for
basic mobile computer operation, only experienced users should modify the content of this partition.

•

Application: The Application FFS partition is used to store application programs needed to operate the mobile
computer.

Working with FFS Partitions

Because the FFS partitions appear as folders under the Windows CE file system, they can be written to and read
like any other folder. For example, an application program can write data to a file located in the Application folder
just as it would to the Windows folder. However, the file in the Application folder is in non-volatile storage and is not
lost on a cold boot (e.g., when power is removed for a long period of time).

Standard tools such as ActiveSync can be used to copy files to and from the FFS partitions. They appear as the
“Application” and “Platform” folders to the ActiveSync explorer. This is useful when installing applications on the
mobile computer. Applications stored in the Application folder are retained even when the mobile computer is cold
booted.

There are two device drivers included in the Windows CE image to assist developers in configuring the mobile
computer following a cold boot: RegMerge and CopyFiles.

RegMerge.dll

RegMerge.dll is a built-in driver that allows registry edits to be made to the Windows CE Registry. Regmerge.dll
runs very early in the boot process and looks for registry files (.reg files) in certain Flash File System folders during
a cold boot. It then merges the registry changes into the system registry located in RAM.

Since the registry is re-created on every cold boot from the default ROM image, the RegMerge driver is necessary
to make registry modifications persistent over cold boots.

RegMerge is configured to look in the root of two specific folders for .reg files in the following order:

\Platform

\Application

Regmerge continues to look for .reg files in these folders until all folders are checked. This allows folders later in
the list to override folders earlier in the list. This way, it is possible to override Registry changes made by the