Summary: Providing Persistent Objects in Distributed Systems
Barbara Liskov, Miguel Castro, Liuba Shrira?, Atul Adya
Laboratory for Computer Science,
Massachusetts Institute of Technology,
545 Technology Square, Cambridge, MA 02139
Abstract. THOR is a persistent object store that provides a powerful programming
model. THOR ensures that persistent objects are accessed only by calling their
methods and it supports atomic transactions. The result is a system that allows
applications to share objects safely across both space and time.
The paper describes how the THOR implementation is able to support this pow-
erful model and yet achieve good performance, even in a wide-area, large-scale
distributed environment. It describes the techniques used in THOR to meet the
challenge of providing good performance in spite of the need to manage very
large numbers of very small objects. In addition, the paper puts the performance
of THOR in perspective by showing that it substantially outperforms a system
based on memory mapped files, even though that system provides much less
functionality than THOR.
Persistent object stores providea powerfulprogrammingmodel for modernapplications.