The Design and Implementation of the Anykernel and Rump Kernels

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4 Evaluation
This chapter evaluated the work in a broad scope. First, evaluate the general feasibility
of the implementation. After that, we evaluate rump kernels as the solutions
for the motivating problems we gave in Section 1.1: development, security and reuse
of kernel code in applications. Finally, we look at performance metrics to measure
that rump kernels perform better than other solutions for our use cases.
4.1 Feasibility
The feasibility of an implementation needs to take into account both the initial effort
and the maintenance effort. Both must be reasonably low for an implementation to
be feasible over a period of time.
feasibility =
1
implementation + maintenance
(4.1)
4.1.1 Implementation Effort
To measure implementation effort we compare the size of the supported driver codebase
against amount of code required for rump kernel support. The complete reimplemented
part along with a selection of supported drivers is presented in Figure 4.1.
The extracted drivers depicted represent only a fraction of the total supported
drivers. In most cases, smaller drivers were included and larger ones were left out;
for example, the omitted FFS driver is three times the size of the FAT driver. From
this data we observe that the amount of driver code supported by a rump kernel is
far greater than the amount of code implemented for supporting them.