Datasheet

VIPER / VIPER-Lite Embedded Linux Development Kit Quickstart Arcom Embedded Linux (AEL)
The file system
The file system used on the VIPER / VIPER-Lite Flash memory is a compressed
Journaling Flash File System (JFFS2). JFFS2 has the following advantages:
Robustness. •
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Power fail safe.
No integrity scan (fsck) is required at boot time.
Flash wear levelling.
Transparent compression, with a typical compression ratio of 2:1.
The on-board Flash is partitioned using RedBoot FIS, as shown in the following table:
Partition # Block device Size (KB) Offset (KB) Description
0 /dev/mtdblock0 124 0 Partition table
1 /dev/mtdblock1 4 124 RedBoot configuration
2 /dev/mtdblock2 remainder 128 Root file system
Previous versions of Arcom Embedded Linux on the VIPER / VIPER-Lite
made use of a separate kernel partition. From version 4 issue 1 onwards, the
kernel is stored as a regular file in the /boot/ folder on the root file system.
In addition, a 4MB RAM-based file system is mounted on /var/tmp for temporary files.
These are lost on reboot.
The basic AEL install uses about 13.9MB of physical Flash. On a board with 32MB of
Flash memory fitted, this leaves about 18.1MB free. This is about 36MB of free space,
assuming a typical 2:1 compression ratio. For a board fitted with 16MB of Flash
memory, there is approximately 2MB of free space. This is about 4MB of free space,
assuming the same compression ratio.
You can make additional space available by removing unused packages. For example,
if you do not require video support, removing xorg and it’s components could release
about 2MB. For more information on removing packages, refer to the AEL Technical
Manual, which is in the /manuals/ folder on the Development Kit CD.
The default Flash image is on the Development Kit CD, in the /images/ folder. For an
explanation of how to reload a complete Flash image, see the AEL Technical Manual.
© 2006 Arcom Issue B 19