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1.3 System Models for Distributed and Cloud ComputingClassification of Massive systems (Table 1.2)

1.3.1 Clusters of Cooperative Computers Cluster Architecture

The architecture of a typical server cluster built around a low-latency, high-bandwidth interconnection network. (Fig. 1.15)

Single-System Image An ideal cluster should merge multiple system images into a single-

system image (SSI). cluster operating system some middleware to support SSI at various levels. An SSI is an illusion created by software or hardware that presents a collection

of resources as one integrated, powerful resource. Critical Cluster Design Issues and Feasible Implementations (Table 1.3)

1.3.2 Grid Computing Infrastructure Computational Grids

Computational grid and data grid providing computing utility, data, and information services through resource sharing and cooperation among participating organizations. (Fig. 1.16)

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Grid Families Grid systems are classified in essentially two categories: computational or

data grids and P2P grids. (Table 1.4)

1.3.3 Peer-to-Peer Network Families P2P Systems

In a P2P system, every node acts as both a client and a server, providing part of the system resources.

The physical network is simply an ad hoc network formed at various Internet domains randomly using the TCP/IP and NAI (Network Access Identifier) protocols.

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Overlay Networks

The overlay is a virtual network formed by mapping each physical machine with its ID, logically, through a virtual mapping as shown in Fig. 1.17.

There are two types of overlay networks: unstructured and structured.

P2P Application Families

Major Categories of P2P Network Families. (Table 1.5)

P2P Computing Challenges

P2P computing faces three types of heterogeneity problem in hardware, software, and network requirements.

P2P performance is affected by routing efficiency and self-organization by participating peers.

Fault tolerance, failure management, and load balancing are other important issues in using overlay networks.

Security, privacy, and copyright violations are major worries by those in the industry in terms of applying P2P technology in business application.

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1.3.4 Cloud Computing Over the Internet

Internet Clouds

Cloud computing applies a virtualized platform with elastic resources on demand by provisioning hardware, software, and data set dynamically. (Fig. 1. 18)

The Cloud Landscape

Three cloud service models in a cloud landscape of major providers. (Fig. 1.19)

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1.4 Software Environments for Distributed Systems and Clouds

1.4.1 Service-Oriented Architecture (SOA)

대규모 컴퓨터 시스템을 구축할 때의 개념으로 업무상에 일 처리에 해당하는 소프트웨어 기능을 서비스로 판단하여 그 서비스를 네트워크상에 연동하여 시스템 전체를 구축해 나가는 방법론 .

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The Evolution of SOA

SOA applies to building grids, clouds, grid of clouds, clouds of grids, clouds of clouds, and systems of system in general.

The evolution of SOA: grids of clouds and grids. (Fig. 1.21)

SOA aims to search for, or sort out, the useful data from the massive amount of raw data items.

Grids versus Clouds

In general, a grid system applies static resources, while a cloud emphasizes elastic resources.

The difference between grids and clouds are limited only in dynamic resource allocation based on virtualization and autonomic computing.

Trends toward Distributed Operating Systems

DOS achieves higher use or system transparency.

A transparent computing environment that separates the user data, OS, and hardware in time and space – an ideal model for cloud computing. (Fig. 1.22)

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1.5 Performance, Security and Energy Efficient Performance Metrics and Scalability Analysis

Performance Metrics MIPS

Mbps

Tflops (tera floating-point operations per second)

TPS (transactions per second)

job response time

network latency

Dimensions of Scalability Size scalability

Software scalability

Application scalability

Technology scalability

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Fault Tolerance and System Availability System Availability

A system is highly available if it has long mean time to failure (MTTF) and a short mean time to repair (MTTR).

System Availability=MTTF/(MTTF+MTTR)

MTTF 는 주어진 시간에서 고장 발생시 까지 시간으로 고장 수리 후 다음 고장까지의 시간을 의미함

Any failure that will be pull down the operation of the entire system is called a single of failure. The rule of thumb is to design a dependable computting system with no single point of failure.

Network Threats and Data Integrity

Threats to Systems and Networks Fig. 1.25 summaries various attack types and their potential damages to use

rs.

Security Responsibilities Three security requirements are often considered: confidentiality, integrity, an

d availability for most Internet service providers and cloud users.

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Energy Efficiency in Distributed Computing

Parallel and distributed computing systems recently encountered new challenging issues including energy efficiency, and workload and resource outsourcing.

클라우드 컴퓨팅은 IT 자원을 외부에 아웃소싱을 함으로 인하여 가장 먼저 대두 되는 것이 ‘보안’에 관련된 문제이다 .