Java Virtual Machines form an important part of the web and business server market. Distributed Java Virtual Machines have the potential to make a significant contribution to industries that utilize this technology. An attractive platform for this purpose is the cluster, a highly cost-effective and scalable parallel computer model. However, realizing on such a platform a high performance virtua...

User Direct Messaging (UDM) allows user-level, processor-to-processor messaging to coexist with general multiprogramming and virtual memory. Direct messaging, where processors launch and receive messages in tens of cycles directly via network interface FIFOs as opposed to indirectly via memory, offers high message bandwidth and low delivery latency by avoiding memory delay and buffer management...

For the purpose of load balancing, migration of VM instances or processes in cloud environment is quite useful. However, the live migration of VM is insecure. There is necessity of incorporating encryption and authentication mechanisms during migration process. An attempt is made to secure live migration of virtual machine and running processes from one machine to another. In this system, the v...

Virtual machine migration (VMM) is one of important services is used as a tool to facilitate system maintenance, load balancing, fault tolerance, on-demand service offerings. Live VMM transfers an active Virtual Machine (VM) from one physical host to another across different data centres. It involves a sequence of operations in iteration under a specific protocol/method for migrating execution ...

Mach; UNIX/OSF; HP-PA; virtually addressed cache architecture; PA-RISC; virtual memory Mach shares memory between tasks by virtual address aliasing. This means a physical page can be mapped to more than one virtual page at a time. This works well on hardware architectures that use a physically addressed cache, but can cause some problems for architectures that use a virtually addressed cache re...

Java is a strong player in the application server market and thus the performance of its virtual machine is an important aspect of a server’s performance. One of the components that affect the performance of a JVM is the memory manager, which also includes the garbage collector. Modern virtual machines offer a multitude of options for tuning the memory manager, which can have a significant impa...

In this paper we formally specify a large subset of Java Virtual Machine instructions based on the descriptions in the Java Virtual Machine Speciication by Lindholm and Yellin, in the Java Speciication by Gosling, Joy and Steele, and based on the behaviors of some test programs on Sun's implementation of the Java Virtual Machine. The formal speciication describes the runtime behaviors of the in...

Virtualization can provide significant benefits in data centers by enabling dynamic virtual machine resizing and migration to eliminate hotspots. We present Sandpiper, a system that automates the task of monitoring and detecting hotspots, determining a new mapping of physical to virtual resources, resizing virtual machines to their new allocations, and initiating any necessary migrations. Sandp...

vNUMA, for virtual NUMA, is a virtual machine that presents a cluster as a virtual shared-memory multiprocessor. It is designed to make the computational power of clusters available to legacy applications and operating systems. A characteristic aspect of vNUMA is that it incorporates distributed shared memory (DSM) inside the hypervisor, in contrast to the more traditional approach of providing...