e.Digital Corporation (fka EDIG)

[But Anyway]

doni, read this:

http://www.intel.com/design/flcomp/applnots/29766505.pdf

Excerpt:

This document provides guidelines for determining the “best fit” file system for use with flash in a particular
implementation. Now that flash technology has matured, is widely available, and has become an industry
standard, more attention is being given to improving the necessary enabling software. The Flash Translation
Layer (FTL) flash driver has emerged as the best flash software solution for removable linear flash card
applications, and is currently being supported by several companies including M-Systems, SCM, Phoenix
Technologies, Annasoft (Annabooks), and SystemSoft. Intel advocates the use of FTL with flash for
applications that need to transfer data back to the PC on the flash media.

However, after discussions with many embedded system developers, Intel realizes that sometimes FTL
solutions may not meet all customers’ needs. This document presents FTL, VFM, FDI, and other software
solutions, and categorizes them for easy understanding. Additionally, a straightforward file system selection
tree is presented as an aid in determining the best implementation for your system.

It is important to understand that each file system has its own strengths and weaknesses, and that there is no
solution that meets every design’s needs. Helping you determine which file system best meets your need is
the goal of this document.

Intel is committed to supporting our customers. If you are interested in flash, want to know about flash, or
want to understand the different file systems that support flash, then contact your nearest Intel
representative.

Figure 1 illustrates the different file system categories for flash support. Each category may have multiple
implementations. For example, in the “Sector-Based” category, we list several implementations, each with a
different set of features.

The columns in Figure 1 represent the three major types of file system implementations for flash. The
Sector-Based category uses small, equally-sized blocks of memory, sometimes called sectors, to emulate a
“drive-like” implementation.

Figure 2 lays out much of the same information as Figure 1, but presents it in a slightly different format.

Figure 2 also provides the status of various software file system products Intel is providing/investigating.

Figure 3 provides a file system/manager selection tree. By starting at the top of the page and answering the
questions, you can determine the “best fit” file system to meet your needs. Some of these file systems are
offered by third-party vendors like M-Systems, SystemSoft, and SCM. The rest of the file systems are
offered to OEM Intel Flash customers by Intel Corporation as reference code.