Datasheet

VIPER Embedded Linux Development Kit Quickstart Arcom Embedded Linux (AEL)

The file system

The file system used on the VIPER Flash memory is a compressed Journaling Flash

File System (JFFS2). JFFS2 has the following advantages:

Robustness. •

•

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 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 filesystem.

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 7.9MB of physical Flash. On a board with 32MB of

Flash memory fitted, this leaves about 24.1MB free. This is about 50MB of free space,

assuming a typical 2:1 compression ratio. You can make additional space available by

removing unused packages. For more information, 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.