Use Write Filters with USB Boot
3/21/2011
Windows Embedded Standard 7 supports booting from Universal Serial Bus (USB) mass-storage devices, such as USB hard drives and USB flash drives (UFDs). Given the wide availability of external USB ports on computer boards and the quickly falling cost of USB drives, USB boot media are a cost-effective alternative to compact flash media.
You can use EWF or FBWF to protect the boot partition on USB media. Although USB Boot can work on its own, there are several advantages in using USB Boot with FBWF or EWF. Typical UFDs have poor write rates (approximately 10 to 20 MB/second for sequential writes), while both sequential and random reads are 2 to 3 times faster.
By using write filters you can take advantage of the UFD read characteristics without the penalty of slower write rates for your data, persisting only the information required for your applications.
For more information, see Build a Bootable USB Image.