The Design and Implementation of the Anykernel and Rump Kernels

190
120
build time (minutes)
100
80
60
40
20
0
rumptest GENERIC ALL build
Figure 4.3: Duration for various i386 target builds. The targets with names
written in capital letter are kernel-only builds for popular test configurations. Prior
to the introduction of the rumptest target, the build target was the fastest way to
check that modifications to kernel code did not introduce build problems for rump
kernels.
The rumptest command is not a substitute for a full OS build, but it addresses a
practical concern of attaining “99%” certainty of the correctness of kernel changes in
1/30th of the time required for a full build. Build times are presented in Figure 4.3.
The addition of the rumptest command addressed the problem: it made build-testing
quick and obvious.
4.2 Use of Rump Kernels in Applications
4.2.1 fs-utils
Userspace implementations of file system drivers exist. For example, there is mtools [89]
for FAT file systems, e2fsprogs [2] for ext2/3/4, isoread for CD9660 and ntfsprogs