Datasheet

ZEUS Embedded Linux Development Kit Quickstart AEL Embedded Linux

The file system

The file system used on the on-board Flash is a compressed Journaling Flash File

System (JFFS2). JFFS2 has the following advantages:

• Robustness.

• 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 on-board 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 256 0 RedBoot

1 /dev/mtdblock1 (remainder) 256 Filesystem

2 /dev/mtdblock2 124 128 (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 Embedded Linux install uses about 14MB of physical Flash. On a board

with 32MB of Flash memory fitted, this leaves about 18MB free. This is about 36MB of

free space, assuming a typical 2:1 compression ratio.

You can make additional space available by removing unused packages. For example,

if you do not require video support, removing xorg and its components could release

about 2MB. For more information on removing packages, refer to the AEL Embedded

Linux 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 Embedded Linux Technical Manual for an explanation of

how to reload a complete Flash image.