Jong Hyuk Choi

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We present a new arrangement of directory bits called the segment directory to improve directory storage efficiency: a segment directory can point to several sharing processors with almost the same number of bits as the pointer which can point to only one. Many directory overflows can be eliminated by using the segment directory element in place of the(More)
Commercial Scale-Out is a new research project at IBM Research. Its main goal is to investigate and develop technologies for the use of large scale parallelism in commercial applications, eventually leading to a commercial su-percomputer. The project leverages and explores the features of IBM's BladeCenter family of products. A significant challenge in(More)
This paper presents a mesh with virtual buses as the bandwidth-efficient implementation of the mesh with multiple broadcasting on which many computational problems can be solved with reduced time complexity. The new system provides a low latency and high bandwidth communication mechanism without the disadvantage of the dual network approach: the possible(More)
As an integral part of the Web Services Security (WS-Security), directory services are used to store and access X.509 certificates. Lightweight Directory Access Protocol (LDAP) is the predominant directory access protocol for the Internet, and hence for the Web services. Values of LDAP attribute and assertion value syntaxes, though defined using ASN.1, are(More)
This paper describes our effort to improve the performance of the connection management subsystem of the OpenLDAP directory server. Two proposed architec-tures, the multi-listener and the lightweight listener architectures will be described and compared to each other in this paper. This paper will also describe our effort to improve the synchronization of(More)
Most distributed shared memory systems use point-to-point networks in conjunction with directory-based cache coherence protocols. Cache invalidation transaction generates a number of unicast invalidation messages and as many acknowledgment messages. This results in heavy network traffic, high latency, and high occupancy at home nodes. This paper introduces(More)
This paper presents an adaptive limited pointers directory scheme which works better than the broadcast and the non-broadcast limited pointers schemes. The former is good at workloads comprising mostly-read data and the latter is good at workloads comprising frequently read / write data. The proposed adaptive scheme dynamically switches between the two(More)