The Design and Implementation of the Anykernel and Rump Kernels

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for NTFS. The benefit is that file systems can be accessed in userspace without
kernel support or privileges. The downside is that all tools use different command
line arguments. Another drawback is that if a userspace driver for a file system is
not implemented, such a utility does not exist.
The fs-utils project [116] attached standard NetBSD file utilities (ls, cat, mv, etc.)
to rump kernel file system drivers as local clients. There are two benefits to this
approach:
1. standard command line parameters are preserved i.e. ls accepts the familiar
-ABcFhL parameter string
2. all NetBSD file systems with kernel drivers are supported
The only exception to command line arguments is that the first parameter is interpreted
as the location specifier the file system is mounted from. The tools make
an attempt to auto-detect the type of file system, so passing the file system type is
optional. For example, fsu_ls /dev/rwd0a -l might list the contents of a FFS on
the hard drive, while fsu_ls 10.181.181.181:/m/dm -l would do the same for
an NFS export 14 .
We conclude it is possible to use rump kernels as application libraries to implement
functionality which was previously done using userspace reimplementations of
drivers.
14 In case of NFS, the sockin networking facility (Section 3.9.1) is used, so no TCP/IP stack
configuration is required.