genromfs - create a romfs image
genromfs -f device
[ -d source
] [ -V label
] [ -A alignment,pattern
] [ -x pattern
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.
will scan the current directory and its subdirectories, build a
romfs image from the files found, and output it to the file or device you
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
type can be b
for block devices,
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
- -f output
- Specifies the file to output the image to. This option is
- -d source
- Use the specified directory as the source, not the current
- -V label
- Build the image with the specified volume label. Currently
it is not used by the kernel, but it will be recorded in the image.
- -a alignment
- 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.
- -A alignment,pattern
- 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).
- -x pattern
- Allow to exclude files that match a pattern. It's useful to
exclude CVS directories and backup files (ending in a '~').
- 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
new romfs filesystem image.
genromfs -d root -f /dev/fd0 -A 2048,/.. -A '4096,*.boot' -a 512 -V 'Bootable floppy'
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
<firstname.lastname@example.org>, for the Debian GNU/Linux system.