Stec UFM 4GB SLUFM4GU2TU-A User Manual
Product codes
SLUFM4GU2TU-A
SLUFMxxxU2TU(I)-y Data Sheet
STEC™ Embedded USB Flash Module
61000-07022-108, September 2012
9
3.2.3 Error Correction
The USB 2.0 Interface Controller implements an advanced Error Correction scheme, based on the BCH
error correct algorithm. The ECC engine can correct up to 16 bits per 1 KByte. To ensure the fastest
performance, correction is done on-the-fly, in hardware only.
error correct algorithm. The ECC engine can correct up to 16 bits per 1 KByte. To ensure the fastest
performance, correction is done on-the-fly, in hardware only.
Each time the host application writes a sector of 512 bytes to the embedded USB flash module, a unique
ECC signature is created by the ECC engine and written together with the data to the flash. When the data
is read back by the host, the ECC engine creates again the unique ECC signature. It will then compare the
original written signature with the newly created signature, and sets an error flag if the two signatures are
not the same. Correction of the data is done on-the-fly when the error flag is set, and the data presented
to the host will be the same as the original written data. This powerful Error Correction scheme results in
an Uncorrectable Bit Error Rate (UBER) of less than 1 in 10
ECC signature is created by the ECC engine and written together with the data to the flash. When the data
is read back by the host, the ECC engine creates again the unique ECC signature. It will then compare the
original written signature with the newly created signature, and sets an error flag if the two signatures are
not the same. Correction of the data is done on-the-fly when the error flag is set, and the data presented
to the host will be the same as the original written data. This powerful Error Correction scheme results in
an Uncorrectable Bit Error Rate (UBER) of less than 1 in 10
14
bits, read.
3.3
OS and Boot Support
The embedded USB flash module can be used as the OS boot and main storage device for most
Microsoft Operating Systems, as well as most embedded Operating Systems, as listed in Table 8 When
used as the OS boot and main storage device, the embedded USB flash module is recognized as the
fixed hard drive in the system.
Microsoft Operating Systems, as well as most embedded Operating Systems, as listed in Table 8 When
used as the OS boot and main storage device, the embedded USB flash module is recognized as the
fixed hard drive in the system.
Table 8: Supported Operating Systems
Operating System
Secondary Storage
Boot and Main
Storage
Version
Windows Vista/7
√
Conditional
Windows XP Pro
√
√
Windows XP Embedded
√
√
Service Pack 2007
Windows CE
√
√
4.2 and 5.0
Windows for POS (WEPOS)
√
-
VxWorks
√
√
6.1 and up
Linux
√
√
Kernel 2.4 and up
Note: When using the embedded USB flash module as the OS boot device, it should be verified that the
system BIOS supports booting from a USB device. Please contact your BIOS vendor to verify this.
system BIOS supports booting from a USB device. Please contact your BIOS vendor to verify this.
3.3.1 Using USB Flash Module with XP Embedded
When using embedded USB flash module with Windows XP Embedded, it is recommended that the
Enhanced Write Filter (EWF) feature is implemented. The EWF intercepts calls at the sector level, and
thereby eliminates many file system updates/writes to the flash. Windows XP Embedded Service Pack 2
Feature Pack 2007 introduced an additional write protect feature, called File Based Write Filter (FBWF).
The new FBWF function write-protects embedded devices at the file level, in contrast to the EWF, which
has been protecting devices at the sector level.
Enhanced Write Filter (EWF) feature is implemented. The EWF intercepts calls at the sector level, and
thereby eliminates many file system updates/writes to the flash. Windows XP Embedded Service Pack 2
Feature Pack 2007 introduced an additional write protect feature, called File Based Write Filter (FBWF).
The new FBWF function write-protects embedded devices at the file level, in contrast to the EWF, which
has been protecting devices at the sector level.
FBWF and EWF, combined with the built-in wear leveling algorithm, ensure that the maximum life span of
the flash device is achieved.
the flash device is achieved.