Summary: Transforming Policies into Mechanisms with Infokernel
Andrea C. Arpaci­Dusseau, Remzi H. Arpaci­Dusseau, Nathan C. Burnett, Timothy E. Denehy,
Thomas J. Engle, Haryadi S. Gunawi, James A. Nugent, and Florentina I. Popovici
Department of Computer Sciences, University of Wisconsin ­ Madison
{dusseau, remzi, ncb, tedenehy, englet, haryadi, damion, popovici}@cs.wisc.edu
ABSTRACT
We describe an evolutionary path that allows operating sys­
tems to be used in a more flexible and appropriate manner
by higher­level services. An infokernel exposes key pieces of
information about its algorithms and internal state; thus,
its default policies become mechanisms, which can be con­
trolled from user­level. We have implemented two prototype
infokernels based on the Linux 2.4 and NetBSD 1.5 kernels,
called infoLinux and infoBSD, respectively. The infokernels
export key abstractions as well as basic information prim­
itives. Using infoLinux, we have implemented four case
studies showing that policies within Linux can be manipu­
lated outside of the kernel. Specifically, we show that the
default file cache replacement algorithm, file layout policy,
disk scheduling algorithm, and TCP congestion control algo­

Source: Arpaci-Dusseau, Remzi - Department of Computer Sciences, Department of Computer Sciences, University of Wisconsin at Madison
Liblit, Ben - Department of Computer Sciences, University of Wisconsin at Madison

Collections: Computer Technologies and Information Sciences