VULCAN Quickstart
Arcom Embedded Linux
The file system
The file system used on the VULCAN Flash is a compressed Journaling Flash File
System (JFFS2). JFFS2 has the following advantages:
Robustness.
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A power fail-safe mechanism.
No integrity scan (fsck) is required at boot time.
Flash wear levelling.
Transparent compression with a typical compression ratio of 2:1.
The onboard Flash is partitioned using RedBoot FIS.
The following table shows the default Flash layout:
Partition # Block device
Size (KB) Offset
(KB) Description
0 /dev/mtdblock0
384 0
RedBoot
1 /dev/mtdblock1
(remainder)
384 Filesystem
2
/dev/mtdblock2
60
64 (from end) RedBoot FIS partition table
3
/dev/mtdblock3
4
4 (from end)
RedBoot configuration
In addition, a 4MB RAM based file system is mounted on /var/tmp for temporary files.
These are lost during reboot.
The basic AEL install uses about 8MB of physical Flash. On a board with 16MB of
Flash memory fitted, this leaves about 7.5MB free. This is about 15MB of free space,
assuming a typical 2:1 compression ratio. Additional space can be made available by
removing unused packages. Refer to the AEL Technical Manual, which is in the
/manuals/ folder on the Development Kit CD.
The default Flash image is available from the /images/ folder on the Development Kit
CD. Please refer to the AEL Technical Manual for an explanation of how to reload a
complete Flash image.
© 2005 Arcom Issue D
18
