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Chapter 9. Reference
This was not always empty, prior to 2007/05/02 the EXTRA_IMAGECMD variable for jffs2 was
set to enable padding, to define the endianess and to specify the block size:
EXTRA_IMAGECMD_jffs2 = "--pad --little-endian --eraseblock=0x40000"
cramfs
Creates cramfs "Compression ROM file system" images. This is a read only compressed filesystem
which is used directly by decompressing files into RAM as they are accessed. Files sizes are limited
to 16MB, file system size is limited to 256MB, only 8-bit uids and gids are supported, no hard links
are supported and no time stamps are supported.
IMAGE_CMD_cramfs = "mkcramfs ${IMAGE_ROOTFS} \
${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.cramfs \
${EXTRA_IMAGECMD}"
The EXTRA_IMAGECMD variable for cramfs is passed to mkcramfs and is left empty by
default:
EXTRA_IMAGECMD_cramfs = ""
ext2
Creates an "Extended Filesystem 2" image file. This is the standard Linux non-journaling file
system.
IMAGE_CMD_ext2 = "genext2fs -b ${IMAGE_ROOTFS_SIZE} \
-d ${IMAGE_ROOTFS} \
${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.ext2 \
${EXTRA_IMAGECMD}"
The EXTRA_IMAGECMD variable for ext2 is passed to genext2fs and is left empty by default:
EXTRA_IMAGECMD_ext2 = ""
The IMAGE_ROOTS_SIZE variable is used to specify the size of the ext2 image and is set to 64k
by default:
IMAGE_ROOTFS_SIZE_ext2 = "65536"
ext3
Creates an "Extended Filesystem 3" image file. This is the standard Linux journaling file system.
IMAGE_CMD_ext3 = "genext2fs -b ${IMAGE_ROOTFS_SIZE} \
-d ${IMAGE_ROOTFS} \
${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.ext3 \
${EXTRA_IMAGECMD}; \
tune2fs -j ${DEPLOY_DIR_IMAGE}/tmp.gz/${IMAGE_NAME}.rootfs.ext3"
The EXTRA_IMAGECMD variable for ext3 is passed to genext2fs and is left empty by default:
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