diff options
Diffstat (limited to 'Documentation/filesystems/ramfs-rootfs-initramfs.txt')
| -rw-r--r-- | Documentation/filesystems/ramfs-rootfs-initramfs.txt | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/Documentation/filesystems/ramfs-rootfs-initramfs.txt b/Documentation/filesystems/ramfs-rootfs-initramfs.txt index 7be232b44ee..b176928e696 100644 --- a/Documentation/filesystems/ramfs-rootfs-initramfs.txt +++ b/Documentation/filesystems/ramfs-rootfs-initramfs.txt @@ -79,6 +79,10 @@ to just make sure certain lists can't become empty. Most systems just mount another filesystem over rootfs and ignore it. The amount of space an empty instance of ramfs takes up is tiny. +If CONFIG_TMPFS is enabled, rootfs will use tmpfs instead of ramfs by +default. To force ramfs, add "rootfstype=ramfs" to the kernel command +line. + What is initramfs? ------------------ @@ -130,12 +134,12 @@ The 2.6 kernel build process always creates a gzipped cpio format initramfs archive and links it into the resulting kernel binary. By default, this archive is empty (consuming 134 bytes on x86). -The config option CONFIG_INITRAMFS_SOURCE (for some reason buried under -devices->block devices in menuconfig, and living in usr/Kconfig) can be used -to specify a source for the initramfs archive, which will automatically be -incorporated into the resulting binary. This option can point to an existing -gzipped cpio archive, a directory containing files to be archived, or a text -file specification such as the following example: +The config option CONFIG_INITRAMFS_SOURCE (in General Setup in menuconfig, +and living in usr/Kconfig) can be used to specify a source for the +initramfs archive, which will automatically be incorporated into the +resulting binary. This option can point to an existing gzipped cpio +archive, a directory containing files to be archived, or a text file +specification such as the following example: dir /dev 755 0 0 nod /dev/console 644 0 0 c 5 1 @@ -263,7 +267,7 @@ User Mode Linux, like so: sleep(999999999); } EOF - gcc -static hello2.c -o init + gcc -static hello.c -o init echo init | cpio -o -H newc | gzip > test.cpio.gz # Testing external initramfs using the initrd loading mechanism. qemu -kernel /boot/vmlinuz -initrd test.cpio.gz /dev/zero @@ -297,7 +301,7 @@ the above threads) is: either way about the archive format, and there are alternative tools, such as: - http://freshmeat.net/projects/afio/ + http://freecode.com/projects/afio 2) The cpio archive format chosen by the kernel is simpler and cleaner (and thus easier to create and parse) than any of the (literally dozens of) |