genromfs - create a romfs image
genromfs -f device [ -d source ] [ -V label ] [ -a alignment ] [ -A
alignment,pattern ] [ -x pattern ] [ -v ]
genromfs is used to create a romfs file system image, usually directly
on a block device, or for test purposes, in a plain file. It is the
mkfs equivalent of other filesystems.
genromfs will scan the current directory and its subdirectories, build
a romfs image from the files found, and output it to the file or device
During scanning, it recognizes a special notation. If a file begins
with the @ sign (and is empty otherwise), it refers to a device special
node in the format: @name,type,major,minor. type can be b for block
devices, c for character devices, and p for fifos. The linux virtual
console 1 can thus be included as a file with the name: @tty1,c,4,1
Specifies the file to output the image to. This option is
Use the specified directory as the source, not the current
Build the image with the specified volume label. Currently it
is not used by the kernel, but it will be recorded in the image.
Align regular files to a larger boundary. genromfs will align
data of each regular file in the resulting image to the
specified alignment, while keeping the image compatible with the
original romfs definition (by adding pad bytes between last node
before the file and file’s header). By default, genromfs will
guarantee only an alignment of 16 bytes.
Align objects matching shell wildcard pattern to alignment
bytes. If one object matches more patterns, then the highest
alignment is chosen. Alignment has to be a power of two.
Patterns either don’t contain any slashes, in which case files
matching those patterns are matched in all directories, or start
with a leading slash, in which case they are matched against
absolute paths inside of the romfs filesystem (that is, as if
you chrooted into the rom filesystem).
Allow to exclude files that match a pattern. It’s useful to
exclude CVS directories and backup files (ending in a ’~’).
-v Verbose operation, genromfs will print each file which is
included in the image, along with its offset.
genromfs -d root -f /dev/fd0 -V ’Secret labs install disk’
All files in the root directory will be written to /dev/fd0 as a new
romfs filesystem image.
genromfs -d root -f /dev/fd0 -A 2048,/.. -A ’4096,*.boot’ -a 512 -V
Generate the image and place file data of all regular files on 512
bytes boundaries or on 4K boundaries, if they have the .boot extension.
Additionally, align the romfs header of the ’..’ entry in the root
directory on a 2K boundary. Effectively, this makes sure that the
romfs image uses the least possible space in the first 2048 bytes.
You can use the generated image (if you have the romfs module loaded,
or compiled into the kernel) via:
mount -t romfs /dev/fd0 /mnt
This manual page was initially written by Christoph Lameter
<email@example.com>, for the Debian GNU/Linux system.
mkfs(8), mount(8), mkisofs(8)