W406-CE User’s Manual
Introduction
An SD card has its own life cycle. Since most SD cards are made from a NAND Flash, their
hardware controllers implement BBM. This feature allows FAT to skip bad blocks if they exist.
Furthermore, the memory space of an SD card is much larger than that of the NOR Flash. Using
this space cautiously will ensure that its life cycle is not exceeded. When creating a file for storing
log data, we suggest creating a large empty file (e.g., 30 MB), and then writing data evenly to that
space. When the space is used up, the program rewinds the write operations. As a result, the
number of write operations to each block is reduced.
Using a RAM File System instead of a Flash File System
Even though data in the RAM file system will be deleted after shutting off the power, using the
RAM file system has several advantages over using the Flash file system, including faster
read/write access and not needing to deal with the life cycle issue.
For important applications that relay data back to the host directly, you should write the necessary
log data to the RAM file system. After the host accesses the data, the application erase the data,
freeing up the memory space for further use.
The embedded computer has limited resources, and designers should decide if storing data in a file
system is really necessary. If it is necessary, be sure to choose the most appropriate file system.
Hive-based Registry
The W406 uses a hive-based registry, not a RAM-based registry. A hive-based registry stores
registry data inside files, or hives, which can be kept on any file system. This removes the need to
perform a backup and restore on power off.
Under default settings, registry data will be auto flushed. If
AutoFlush
is disabled, the
RegFlushKey
function is needed to change the registry value in your applications. The
AutoFlush.exe
utility is provided to change the auto-flush setting.
Type
autoflush -d
to disable the auto-flush setting.
\>autoflush -d
Or type
autoflush -e
to enable the auto-flush setting.
\> autoflush -e
Or just type
autoflush
to display the current status.
Connect to Network via Ethernet
The W406 computer offers a 10/100M RJ-45 Ethernet port for network redundancy.
Cellular Networking
The W406 computer has been embedded with a GSM/GPRS/EDGE cellular module for a reliable
and stable wireless communication. It supports quad-band GSM/GPRS/EDGE 850/900/1800/1900
MHz, and GPRS/EDGE Class 10. Meanwhile, it offers SMS tunnel mode for auto configuration
and SIM card authentication.
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