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Summary: Life or Death at Block-Level
Muthian Sivathanu, Lakshmi N. Bairavasundaram,
Andrea C. Arpaci-Dusseau, and Remzi H. Arpaci-Dusseau
Computer Sciences Department
University of Wisconsin, Madison
{muthian, laksh, dusseau, remzi}@cs.wisc.edu
Abstract
A fundamental piece of information required in intelligent stor-
age systems is the liveness of data. We formalize the notion of
liveness within storage, and present two classes of techniques for
making storage systems liveness-aware. In the explicit notifica-
tion approach, we present robust techniques by which a file sys-
tem can impart liveness information to storage through a "free
block" command. In the implicit detection approach, we show
that such information can be inferred by the storage system ef-
ficiently underneath a range of file systems, without changes to
the storage interface. We demonstrate our techniques through
a prototype implementation of a secure deleting disk. We find
that while the explicit interface approach is desirable due to its
simplicity, the implicit approach is easy to deploy and enables
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