基于Java语言的操纵体系设计与实现技术研讨

1、基于Java语言的操纵体系设计与实现技术研讨        【中文摘要】跟着网络技术的敏捷发铺,人们对普适盘算的需求越来越高。传统的操纵体系加中间件的方式已经不能知足普适盘算的需求。普适盘算须要既具有平台无关性又具有高安全性的新型操纵体系。应用Java语言来开发操纵体系不仅可以实现平台无关性,而且可以解决缓冲区溢出等安全题目。但是Java操纵体系为我们带来优势的同时,也带来了良多挑战。本文分离针对Java操纵体系的体系构造设计、Java对象行为规律、全体系垃圾收集算法以及Java操纵体系的实现技术铺开深入研讨。体系

2、构造的设计是操纵体系技术的基本。本文结合Java语言的特色,研讨了Java操纵体系的体系构造设计技术。在新的体系构造下,研讨了以JTOC(Java Table of Contents)为基本的入程软隔离技术,通过肯定入程的“内存边界”和“接口边界”来实现入程间的隔离。提出Java操纵体系须要将垃圾收集技术和体系的存储管理相结合实现全体系的垃圾收集技术,从而实现安全高效自动的内存管理。Java对象性命行为规律可认为垃圾收集算法的设计提供主要依据,但目前对Java运行时程序行为的剖析仍是基于10多年前的统计数据,因为当时的软硬件环境和现在差异较大,所以前人的剖析数据已经不能知足需求。本文设计实现了

3、Java对象性命行为的追踪统计框架和E-Merlin程序准确追踪算法,实现了对象性命行为的追踪。应用此框架对SPECjvm98中的测试程序入行追踪后,通过对追踪结果入行解析和统计发现:1)Java对象几乎平均分布在5个范围之内,每类对象中,边界对象占绝大多数;2)Java对象在内存中的组织相似一个深度很浅的大胖树,在根下,挂了良多小的Java对象簇,而且对象聚集成簇的现象非常普遍。目前的垃圾收集算法都是针对应用入程设计的,如果直接作为体系的垃圾收集算法,因为不能和体系的内存管理相配合,所以机能低下。本文在深入研讨了经典垃圾收集算法(引用计数、标志清扫、半区复制和分代算法)和新型垃圾收集算法(火

4、车算法,Mark-Copy算法)原理的基本上,基于Mark-Copy算法,应用体系内存管理机制和Java对象的内存行为规律,设计实现了全体系垃圾收集算法FSMC(Full System Mark-Copy)。经由测试,FSMC算法相对于Mark-Copy算法节省了20%以上的时光,取得了较好的后果。本文基于X86平台设计实现了Junicorn原型体系。Junicorn体系的硬件抽象层采取C和汇编语言实现,完成体系的引导和硬件装备的初始化并对上层提供基本的硬件控制与中止处置服务。微内核层基于JikesRVM实现了动态编译引擎,基于分代式垃圾收集算法实现了体系垃圾收集器,并设计了中止异常服务框架,

5、目前可以处置X86中的大多数异常(如缺页异常,除法异常等),提供了时钟中止和键盘中止处置服务。目前Junicron支持键盘和显示器两种装备,可以在华硕EPC上运行SPECjvm98中的测试程序。');【Abstract】 With the network technology developing rapidly, people inquire more and more about ubiquitous computing. The traditional technology which combines operating system and midware together

6、can not satisfy the need of ubiquitous computing. Ubiquitous computing requires a new kind of operating system which is both platform-independent and highly-secure. Using Java language to implement this type of operating system not only can make the system platform-independent, but also can solve sa

7、fety threats such as buffer-overflow-attack. Using Java to implement an operating system will bring us a lot of advantages, also it will introduce some challenges. This thesis deeply studies the architecture design of Java operating system, behavior rules of Java objects, full system garbage collect

8、ion algorithm and the implementing technology of Java operating system.The architecture design is the basic of operating system technology. According to the features of Java language, this thesis designs the architecture of Java operating system, under the new architecture, studies the technology of

9、 software-isolation among processes which based on the JTOC (Java Table of Contents) can define the memory and inte*ce border. In order to make the system memory management secure and efficient, this thesis put forwards the idea which should integrate the garbage collection and system management tog

10、ether to implement full-system garbage collection.Life behavior rules of Java objects can provide important evidence for the design of garbage collection algorithms, but the analysis of Java program behavior using data which was gathered more than ten years ago and is not suitable for current applic

11、ations because of the differences in hardware and software. This thesis designs a new framework and implements E-Merlin tracing algorithm to trace the behavior of every Java object. After using this framework to trace programs in SPECjvm98, we discover two basic rules about Java objects. First, Java

12、 objects typically distribute equally in five categories and in each category, broader objects account for large percents. Second, the structure of Java objects in memory is just like a broad fat-tree which is flat. There are a lot of objects directly attach to the root object.All of garbage collect

13、ion algorithms are designed for processes currently, not for operating systems. To use them directly as the garbage collection algorithms of operating system will be inefficient, because they could not cooperate with the mechanism of memory management effectively. This thesis deeply studies the prin

14、ciple of four classic garbage collection algorithms (reference count, mark-sweep, semi-space and generation algorithm) and two new algorithms (train and mark-copy algorithm), and analyses the advantages and shortages of every algorithm. Using the principle of Mark-Copy algorithm and behavior rules o

15、f Java objects, this thesis designs and implements a new full system algorithm named FSMC. According to the test results, FSMC improves the performance by 20% compared with Mark-Copy, which is very efficient.This thesis implements a prototype of Java operating system named Junicorn on the X86 platfo

16、rm. The hardware abstract layer of Junicorn, which is implented in C and assemble language, accomplishes system booting and the initialization of hardware, provides basic hardware control and interrupt management service for micro-kernel. The micro-kernel of Junicorn implements the dynamic compiling engine and full system gar