Specifications

9.2. The TMPFS Virtual Memory Filesystem
9.2.1. Mount Parameters◊
9.2.2. Kernel Support for tmpfs◊
9.2.3. Usage of tmpfs in Embedded Systems◊
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9.3. Using MultiMediaCards in Linux"♦
9.4. Splash Screen Support in Linux♦
9.5. Root File System: Design and Building
9.5.1. Root File System on a Ramdisk◊
9.5.2. Root File System on a JFFS2 File System◊
9.5.3. Root File System on a cramfs File System◊
9.5.4. Root File System on a Read-Only ext2 File System◊
9.5.5. Root File System on a Flash Card◊
9.5.6. Root File System in a Read-Only File in a FAT File System◊
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9.6. Root File System Selection♦
9.7. Overlay File Systems♦
9.8. The Persistent RAM File system (PRAMFS)
9.8.1. Mount Parameters◊
9.8.2. Example◊
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9. Advanced Topics
This section lists some advanced topics of interest to users of U-Boot and Linux.
9.1. Flash Filesystems
9.1.1. Memory Technology Devices
All currently available flash filesystems are based on the Memory Technology Devices MTD layer, so you
must enable (at least) the following configuration options to get flash filesystem support in your system:
CONFIG_MTD=y
CONFIG_MTD_PARTITIONS=y
CONFIG_MTD_CHAR=y
CONFIG_MTD_BLOCK=y
CONFIG_MTD_CFI=y
CONFIG_MTD_GEN_PROBE=y
CONFIG_MTD_CFI_AMDSTD=y
CONFIG_MTD_ROM=y
CONFIG_MTD_m28=y
Note: this configuration uses CFI conformant AMD flash chips; you may need to adjust these settings on
other boards.
The partition layout of the flash devices is contained in the flat device tree for the system (see 13.1. Flat
Device Tree).
Informational messages of the MTD subsystem can be found in the Linux bootlog, i.e. see section 7.5.1.
Bootlog of tftp'd Linux kernel with Root Filesystem over NFS.
One can discover this information in a running system using the proc filesystem:
root@generic-armv5te:~#
root@generic-armv5te:~# cat /proc/mt
9.1.1. Memory Technology Devices 97