[bootlin/training-materials updates] master: Embedded Linux: misc minor improvements (6fe9b5f6)

Michael Opdenacker michael.opdenacker at bootlin.com
Thu Mar 18 12:36:00 CET 2021

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/6fe9b5f6f6876e72645d48f048c74efa62dbba72


commit 6fe9b5f6f6876e72645d48f048c74efa62dbba72
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Thu Mar 18 12:36:00 2021 +0100

    Embedded Linux: misc minor improvements
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


 labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex  |  3 +++
 .../sysdev-block-filesystems/sysdev-block-filesystems.tex   |  3 ++-
 slides/sysdev-embedded-linux/sysdev-embedded-linux.tex      |  6 +++---
 .../sysdev-flash-filesystems/sysdev-flash-filesystems.tex   | 13 ++++++++-----
 4 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex b/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
index 91ea1f93..cf05ad14 100644
--- a/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
+++ b/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
@@ -190,6 +190,9 @@ command \code{nand write}\footnote{The command \code{nand write.trimffs} skips
   not recommended writing more than one time on a page and its OOB
   even if the page is blank.}.
+With the \code{ubi part UBI} command, make sure that U-Boot could process
+the UBI image that you've just flashed.
 \section{Loading kernel and DTB images from UBI and booting it}
 From U-Boot, retrieve the kernel and DTB images from their respective
diff --git a/slides/sysdev-block-filesystems/sysdev-block-filesystems.tex b/slides/sysdev-block-filesystems/sysdev-block-filesystems.tex
index 3b361456..62259fdf 100644
--- a/slides/sysdev-block-filesystems/sysdev-block-filesystems.tex
+++ b/slides/sysdev-block-filesystems/sysdev-block-filesystems.tex
@@ -269,7 +269,8 @@ major minor #blocks name
   \item More space-efficient than ramdisks: files are directly in the
     file cache, grows and shrinks to accommodate stored files
   \item How to use: choose a name to distinguish the various tmpfs
-    instances you could have. Examples:\\
+    instances you have (unlike in most other filesystems, each
+    tmpfs instance is different). Examples:\\
     \code{mount -t tmpfs run /var/run}\\
     \code{mount -t tmpfs shm /dev/shm}
   \item See \kerneldochtml{filesystems/tmpfs} in kernel sources.
diff --git a/slides/sysdev-embedded-linux/sysdev-embedded-linux.tex b/slides/sysdev-embedded-linux/sysdev-embedded-linux.tex
index 9b71ae0b..4c42f915 100644
--- a/slides/sysdev-embedded-linux/sysdev-embedded-linux.tex
+++ b/slides/sysdev-embedded-linux/sysdev-embedded-linux.tex
@@ -522,8 +522,8 @@ met:
     \item Supports hardware encoders and decoders through plugins,
       proprietary/specific plugins are often provided by SoC vendors.
-  \item {\bf alsa-lib}, the user space tools associated to the ALSA sound
-    kernel subsystem
+  \item {\bf alsa-lib}, the user space tools associated to the ALSA
+    kernel sound subsystem
   \item Directly using encoding and decoding libraries, if you decide
     not to use GStreamer:
@@ -915,7 +915,7 @@ met:
     \item The {\em build} space, which will contain a lot more files
       than the {\em target} space, since it is used to keep everything
       needed to {\bf compile} libraries and applications. So we must
-      keep the headers, documentation, and other configuration files
+      keep at least the headers, binaries and configuration files.
diff --git a/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex b/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
index d7426cea..04714a93 100644
--- a/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
+++ b/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
@@ -30,7 +30,7 @@
   \item Encode bits with voltage levels
       \item SLC: {\em Single Level Cell} - 1 bit per memory cell
-      \item MLC: {\em Multi Level Cell} - Multiple bits per cell)
+      \item MLC: {\em Multi Level Cell} - Multiple bits per cell
   \item Start with all bits set to 1
   \item Writing implies changing some bits from 1 to 0
@@ -522,7 +522,7 @@ Device 0 bad blocks:
   \item These file systems are relying on the MTD layer to access
     flash chips
   \item There are several legacy flash filesystems which might be
-    useful for specific usage: JFFS2, YAFFS2.
+    useful for specific uses: JFFS2, YAFFS2.
   \item Nowadays, UBI/UBIFS is the de facto standard for medium to
     large capacity NANDs
@@ -532,6 +532,7 @@ Device 0 bad blocks:
   \frametitle{Legacy flash filesystems: JFFS2}
+    {\em Journaling Flash File System version 2}
     \item Supports on the fly compression
     \item Wear leveling, power failure resistant
@@ -551,6 +552,7 @@ Device 0 bad blocks:
   \frametitle{Legacy flash filesystems: YAFFS2}
+    {\em Yet Another Flash File System version 2}
     \item Mainly supports NAND flash
     \item No compression
@@ -568,9 +570,10 @@ Device 0 bad blocks:
-  \frametitle{UBI/UBIFS}
+  \frametitle{UBI / UBIFS}
+    {\em Unsorted Block Images}
     \item Aimed at replacing JFFS2 by addressing its limitations
     \item Design choices:
@@ -648,7 +651,7 @@ Device 0 bad blocks:
   \item U-Boot now even supports storing its environment in a UBI volume!
   \item If you do need extra MTD partitions, try to group them at the end
-    or the beginning of the flash device
+    or the beginning of the flash device (often more reliable areas).
@@ -851,7 +854,7 @@ Device 0 bad blocks:
       \item \code{-m 4096}, minimal I/O size\\
                  (see \code{/sys/class/mtd/mtdx/writesize}).
-      \item \code{-e 258048}, logical erase block size (smaller than
+      \item \code{-e 258048}, {\bf logical} erase block size (smaller than
                  PEB size, can be found in the kernel log after running
       \item \code{-c 1000}, maximum size of the UBI volume the image

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