计算机英语第十章
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In client-server computing, a network-friendly client version of the application was required on client computers which utilized the client system's memory and CPU for processing, even though resultant application data files (such as processing documents) were stored centrally on the data servers.[3]
7
2 Technologies
8
2 Technologies
Cloud computing is the combined outcome of multiple computer and network technologies such as virtualization, service-oriented architecture (SOA), grid computing and utility computing. They are regarded as a technological evolution. It is they who make cloud computing flexible, reliable and usable.
Creating a virtual machine (VM) over existing operating system and hardware is referred as hardware virtualization. Virtual machines provide an environment that is logically separated from the underlying hardware. The machine on which the virtual machine is created is known as a host machine and virtual machine is referred as a guest machine.
software and data are stored on servers. The major cloud service providers include
Microsoft, Salesforce[5], Amazon, and Google.
Any computer or Web-friendly device connected to the Internet may access the
with no installed client version of an application required.[4]
Typical cloud computing providers deliver common business applications online
that are accessed from another Web service or software like a Web browser, while the
10
2 Technologies
Virtualization
As shown in Figure 10-1, the multi-tenant architecture offers virtual isolation among the multiple tenants. Hence, organizations can use and customize their application as though they each have their instances running.
music, videos, and bookmarks; play games; or do word processing on a remote
server. As data is centrally stored, users do not need to carry a storage medium.
same pool of computing power, applications, and files in a cloud-computing
environment. Users may remotely store and access personal files such as pictures,
计算机英语
Chapter 10 Cloud Computing
1
目录
CONTENT
1 Introduction 2 Technologies 3 Models 4 Architecture 5 Mobile Cloud Computing 6 Challenges
2
Lead in
Cloud computing provides us means of accessing the applications over the Internet. It allows us to create, configure, and customize the applications online.
9
2 Technologies
Virtualization
Virtualization is a technique, which allows sharing single physical instance of an application or resource among multiple organizations or tenants (customers). It does this by assigning a logical name to a physical resource and providing a pointer to that physical resource when demanded.
First of all, cloud computing allows the users to use Web services and resources on demand. One can logon to a Website at any time and use them. Secondly, since cloud computing is completely Web based, it can be accessed from anywhere and at any time. Thirdly, it allows multiple tenants to share a pool of resources. One can share single physical instance of hardware, database and basic infrastructure. Furthermore, it is easy to scale the resources vertically or horizontally at any time. Scaling of resources means the ability of resources to deal with increasing or decreasing demand. In terms of measured service, cloud provider controls and monitors all the aspects of cloud server. Resource optimization, billing, and capacity planning, etc. depend on it.
The term “cloud” is used as a metaphor for a network or Internet. In other words, we can say that cloud is something that is present at remote location. Cloud can provide services over public and private networks, i.e., WAN, LAN or VPN.
With the development of LAN and more networking capabilities, the clientserver model of computing was born, where server computers with enhanced capabilities and large storage devices could be used to host application services and data for a large workgroup.[2]
5
1 Introduction
Cloud computing differs from the classic client-server model by providing
applications from a server that are executed and managed by a client's Web browser,
services.
6
1 Introduction
There are five key characteristics of cloud computing: on-demand selfservice, broad network access, resource pooling, rapid elasticity, and measured service.
Desktop applications that connect to Internet-host E-mail providers may be
considered cloud applications, including Web-based Gmail, Hotmail, or Yahoo! Email
3
1 Introduction
4
1 Intห้องสมุดไป่ตู้oduction
Before cloud computing came into existence, computing tasks such as word processing were not possible without the installation of application software on a user's computer. A user bought a license for each application from a software vendor and obtained the right to install the application on one computer system.
The National Institute of Standards and Technology (NIST) provides a concise and specific definition:
Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.[1]
7
2 Technologies
8
2 Technologies
Cloud computing is the combined outcome of multiple computer and network technologies such as virtualization, service-oriented architecture (SOA), grid computing and utility computing. They are regarded as a technological evolution. It is they who make cloud computing flexible, reliable and usable.
Creating a virtual machine (VM) over existing operating system and hardware is referred as hardware virtualization. Virtual machines provide an environment that is logically separated from the underlying hardware. The machine on which the virtual machine is created is known as a host machine and virtual machine is referred as a guest machine.
software and data are stored on servers. The major cloud service providers include
Microsoft, Salesforce[5], Amazon, and Google.
Any computer or Web-friendly device connected to the Internet may access the
with no installed client version of an application required.[4]
Typical cloud computing providers deliver common business applications online
that are accessed from another Web service or software like a Web browser, while the
10
2 Technologies
Virtualization
As shown in Figure 10-1, the multi-tenant architecture offers virtual isolation among the multiple tenants. Hence, organizations can use and customize their application as though they each have their instances running.
music, videos, and bookmarks; play games; or do word processing on a remote
server. As data is centrally stored, users do not need to carry a storage medium.
same pool of computing power, applications, and files in a cloud-computing
environment. Users may remotely store and access personal files such as pictures,
计算机英语
Chapter 10 Cloud Computing
1
目录
CONTENT
1 Introduction 2 Technologies 3 Models 4 Architecture 5 Mobile Cloud Computing 6 Challenges
2
Lead in
Cloud computing provides us means of accessing the applications over the Internet. It allows us to create, configure, and customize the applications online.
9
2 Technologies
Virtualization
Virtualization is a technique, which allows sharing single physical instance of an application or resource among multiple organizations or tenants (customers). It does this by assigning a logical name to a physical resource and providing a pointer to that physical resource when demanded.
First of all, cloud computing allows the users to use Web services and resources on demand. One can logon to a Website at any time and use them. Secondly, since cloud computing is completely Web based, it can be accessed from anywhere and at any time. Thirdly, it allows multiple tenants to share a pool of resources. One can share single physical instance of hardware, database and basic infrastructure. Furthermore, it is easy to scale the resources vertically or horizontally at any time. Scaling of resources means the ability of resources to deal with increasing or decreasing demand. In terms of measured service, cloud provider controls and monitors all the aspects of cloud server. Resource optimization, billing, and capacity planning, etc. depend on it.
The term “cloud” is used as a metaphor for a network or Internet. In other words, we can say that cloud is something that is present at remote location. Cloud can provide services over public and private networks, i.e., WAN, LAN or VPN.
With the development of LAN and more networking capabilities, the clientserver model of computing was born, where server computers with enhanced capabilities and large storage devices could be used to host application services and data for a large workgroup.[2]
5
1 Introduction
Cloud computing differs from the classic client-server model by providing
applications from a server that are executed and managed by a client's Web browser,
services.
6
1 Introduction
There are five key characteristics of cloud computing: on-demand selfservice, broad network access, resource pooling, rapid elasticity, and measured service.
Desktop applications that connect to Internet-host E-mail providers may be
considered cloud applications, including Web-based Gmail, Hotmail, or Yahoo! Email
3
1 Introduction
4
1 Intห้องสมุดไป่ตู้oduction
Before cloud computing came into existence, computing tasks such as word processing were not possible without the installation of application software on a user's computer. A user bought a license for each application from a software vendor and obtained the right to install the application on one computer system.
The National Institute of Standards and Technology (NIST) provides a concise and specific definition:
Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.[1]