虚拟机动态迁移方法

对虚拟机动态迁移方法的研究背景、研究意义以及研究现状进行综述,分别介绍了内存预拷贝迁移、内存后拷贝迁移、内存混合复制迁移和基于日志跟踪重现的迁移方法,对其算法思想、关键技术、实现机制以及性能等进行概括、分析和比较,并针对当前主流的预拷贝迁移的优化策略予以分类阐述。最后,对动态迁移方法有待深入的研究热点和发展趋势进行展望。     

一种基于资源预分配的虚拟机软实时调度方法

虚拟机技术作为云计算的重要技术之一,近年来得到广泛关注,但是由于虚拟机管理层的存在,导致语义鸿沟,使得实时应用程序、并发程序等在虚拟机上的运行性能受到影响。分析和研究了Xen虚拟机管理器的Credit调度算法,针对其在并发调度和软实时调度方面存在的不足,提出了改进调度算法,实现了算法的调度器原型。新的调度算法对软实时虚拟机进行Credit比例预分配,采用动态调度时间片机制,以non-work-conserving方式实现软实时任务周期调度,保障调度周期满足运行周期要求。通过区分并发和非并发软实时虚拟机,采取不同的调度策略,在满足资源利用率的基础上,确保实时任务的顺利运行。测试结果表明,该调度算法在对并发和非并发软实时任务调度上,具有良好的表现,较好满足了软实时应用调度需求。     

桌面虚拟化技术的现状及未来发展研究

随着全球网络化、信息化的飞速发展,虚拟化技术的应用蓬勃发展,给计算机世界带来全新的革命。本文探讨了桌面虚拟化的现状,分析了桌面虚拟化的发展阶段,以及与服务器虚拟化的区别。并对桌面虚拟化的未来发展,在技术难题攻关上提出了建议。     

Java CLDC在数字电视平台上的移植

实现了Java虚拟机在嵌入式数字电视系统中的移植,并在ST5105DVBT平台上完成测试,对Java虚拟机在数字电视中的应用有重要指导意义。     

Bayes Theorem Based Virtual Machine Scheduling for Optimal Energy Consumption

This paper proposes an algorithm for scheduling Virtual Machines (VM) with energy saving strategies in the physical servers of cloud data centers. Energy saving strategy along with a solution for productive resource utilization for VM deployment in cloud data centers is modeled by a combination of “Virtual Machine Scheduling using Bayes Theorem” algorithm (VMSBT) and Virtual Machine Migration (VMMIG) algorithm. It is shown that the overall data center’s consumption of energy is minimized with a combination of VMSBT algorithm and Virtual Machine Migration (VMMIG) algorithm. Virtual machine migration between the active physical servers in the data center is carried out at periodical intervals as and when a physical server is identified to be under-utilized. In VM scheduling, the optimal data centers are clustered using Bayes Theorem and VMs are scheduled to appropriate data center using the selection policy that identifies the cluster with lesser energy consumption. Clustering using Bayes rule minimizes the number of server choices for the selection policy. Application of Bayes theorem in clustering has enabled the proposed VMSBT algorithm to schedule the virtual machines on to the physical server with minimal execution time. The proposed algorithm is compared with other energy aware VM allocations algorithms viz. “Ant-Colony” optimization-based (ACO) allocation scheme and “min-min” scheduling algorithm. The experimental simulation results prove that the proposed combination of ‘VMSBT’ and ‘VMMIG’ algorithm outperforms other two strategies and is highly effective in scheduling VMs with reduced energy consumption by utilizing the existing resources productively and by minimizing the number of active servers at any given point of time.     

基于监控器时间开销的虚拟机发现方法

针对传统方法只能发现单一类型虚拟机的缺陷,提出基于虚拟机监控器时间开销的虚拟机发现方法。特定指令能使监控器运行时产生显著的额外开销,该方法能利用监控器执行不同指令序列产生的相对时间开销对虚拟机进行判别。实验结果表明,该方法能够准确发现目前3类主流虚拟机。     

嵌入式操作系统面向领域的扩展技术

嵌入式操作系统的扩展技术很好地解决了嵌入式应用可移植性问题，首先介绍了嵌入式操作系统的扩展建模流程，其中需求分析是其重要环节，同时阐述了扩展层的体系结构采用的方法。分析了内核扩展、C／S扩展、OOP和“虚拟机 配置 描述”4种系统扩展方式，并对其优缺点进行了说明。     

Rapid one-of-a-kind production

To shorten the product development cycle time and reduce the cost at the same time, which is very critical for the survival of those small and mid-sized one-of-a-kind production (SMOKP) companies, various computer communication, simulation and computer aided engineering and management techniques have been widely used in these SMOKP companies. However, according to our study, the applications of these advanced computer technologies in these SMOKP companies are lack of system integration and synergy, which result in communication errors, reworks, duplications and hence a longer product development lead time and a higher cost. To solve this problem, an inter/intranet based computer aided rapid product development system is presented in this paper. This system consists of a number of inter/intranet based computer models or sub-systems for supporting rapid development of a one-of-a-kind product. It also employs a novel concurrent product development strategy called “prototype based incremental product development strategy” and an integrated product data structure called “product production structure”. Some industrial implementations of the proposed system, product development strategy and product data structure are also reported in the paper.     

基于分片的云虚拟机安全保护技术

在典型的IaaS云中,用户使用云服务需要通过虚拟机实现。最近有研究表明,在大多数常用的加密协议(如SSL/TLS等)中,至关重要的加密密钥,可能被攻击者通过跨虚拟机的旁路攻击截获。针对这种攻击方式,提出了一种云虚拟机密钥保护系统,通过将加密密钥随机分割为多个分片,并将每个分片存储于不同的虚拟机中,能有效保护云中的加密密钥,抵御各类跨虚拟机的旁路攻击。此外,云虚拟机密钥保护系统会周期性地对加密密钥进行重新分割,即便攻击者能够截获局部的加密密钥,也无法进行还原。将云虚拟机密钥保护系统作为一种对应用软件透明的扩展库,运行在亚马逊EC2云的web服务器,取得了较好的成果。     

有限热源影响下VM循环热泵的热力学分析

对于低温余热,VM循环热泵是一种高效节能的利用途径.文中采用有限时间热力学方法,推导了基于牛顿线性导热定律的内可逆VM循环热泵泵热率的表达式.分析表明:采用VM循环热泵用于地板辐射采暖时,随着有限高温热源的入口温度和有限低温热源进口温度的增加,泵热率将增大;而随着有限高温热源的出口温度和有限低温热源出口温度的增加,泵热率将减小.并且低温有限热源温度的变化对泵热率的影响远大于高温有限热源温度的变化.