[bootlin/training-materials updates] master: Flash storage: minor improvements (97631380)

[Michael Opdenacker]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/976313808ab63ac57bc6325b9c012009c0e53fa0

>---------------------------------------------------------------

commit 976313808ab63ac57bc6325b9c012009c0e53fa0
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Tue Nov 16 08:45:40 2021 +0100

    Flash storage: minor improvements
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


>---------------------------------------------------------------

976313808ab63ac57bc6325b9c012009c0e53fa0
 .../sysdev-flash-filesystems.tex                       | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex b/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
index 3886dcc4..f45aec30 100644
--- a/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
+++ b/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
@@ -66,7 +66,7 @@
     \begin{itemize}
     \item Short lifetime compared to other storage media
     \item Lifetime depends on the NAND flash technology (SLC, MLC):
-      between 1000000 and 1000 erase cycles per block
+      between 1,000,000 and 1,000 erase cycles per block
     \item Wear leveling mechanisms are required to erase blocks evenly
     \item Bad block detection/handling required too
     \end{itemize}
@@ -88,9 +88,9 @@
   \item ECC data are stored in the OOB area
   \item Three algorithms:
     \begin{itemize}
-    \item Hamming: can fixup a single bit per block
-    \item Reed-Solomon: can fixup several bits per block
-    \item BCH: can fixup several bits per block
+    \item Hamming: can fixup a single bit per chunk
+    \item Reed-Solomon: can fixup several bits per chunk
+    \item BCH: can fixup several bits per chunk
     \end{itemize}
   \item BCH and Reed-Solomon strength depends on the size allocated
     for ECC data, which in turn depends on the OOB size
@@ -210,7 +210,7 @@
   \item Example:
   {\scriptsize
   \begin{verbatim}
-# Association between U-Boot name and Linux name
+# Association between U-Boot name and Linux name for the flash device
 setenv mtdids nand0=omap2-nand.0
 # Partition definitions
 setenv mtdparts mtdparts=omap2-nand.0:512k(XLoader)ro,1536k(UBoot)ro,512k(Env),4m(Kernel),-(Root)
@@ -465,8 +465,8 @@ Device 0 bad blocks:
   \item \code{mtd-utils} is a set of utilities to manipulate MTD devices
     \begin{itemize}
     \item \code{mtdinfo} to get detailed information about an MTD device
-    \item \code{flash_erase} to partially or completely erase a given
-      MTD device
+    \item \code{flash_erase} and \code{flash_eraseall} to partially or
+          completely erase a given MTD device
     \item \code{nandwrite} to write to NAND flash
     \item Flash filesystem image creation tools: \code{mkfs.jffs2},
       \code{mkfs.ubifs}, \code{ubinize}, etc.
@@ -989,13 +989,15 @@ ${bootargs_base} ${mtdparts}; bootz 0x81000000 - 0x82000000'}
 \end{frame}
 
 \begin{frame}
-  \frametitle{Useful reading on Linux on raw flash storage}
+  \frametitle{Useful reading}
   \begin{itemize}
   \item Documentation on the linux-mtd website:\\
     \url{http://www.linux-mtd.infradead.org/}
     \begin{itemize}
 	\item You will find answers to your questions there
     \end{itemize}
+  \item Wikipedia's page about ECC:\\
+    \url{https://en.wikipedia.org/wiki/Error_correction_code}
   \end{itemize}
 \end{frame}