17-01-2013, 01:00 PM
Cloud Computing
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History of the term Cloud Computing
The term cloud computing was influenced by some fast-growing Internet companies like Amazon , Google and Yahoo. These companies were providing because of the rapid growth of their user base with the problem of having to hold ever-growing systems (for example, this would be for Amazon Christmas sales) and sufficient performance at peak load times.
For Amazon this peak load in 2006 was higher by a factor of 10 as the base load in daily operations. To address this problem, it was decided to make the architecture and the services that they had to master with the designed in part fluctuating or very high numbers of users and established, to a product that you offer to the outside world, ie that this problem during peak times on the users of the cloud is distributed.
For Amazon this step was the mid-2000s, a logical consequence, since it internally at this time already to small fast-moving teams had changed sides, the new functionalities based on the existing cloud infrastructure implemented. The scale effects of cloud-based services have been so for the product “cloud computing” itself, from which one since there is not only internally but also externally offered.
Definition and levels of Cloud Computing
2009, the National Institute of Standards and Technology (NIST), a definition of Cloud computing, which met with widespread acceptance and combines different approaches to the definition:
Cloud computing describes the three service models:
IaaS – Infrastructure as a Service in Cloud computing – Cloud computing offers virtualized system to access to computer hardware resources such as networks and storage. With IaaS, users freely create their own virtual computer cluster and are therefore responsible for the selection, installation, operation and functioning of their own software.
PaaS – Platform as a Service in Cloud computing – Cloud computing provide access use of programming or run-time environments with flexible, dynamic, customizable screens and data capacity. With PaaS users develop their own software applications or have them perform here, within a software environment that is the service provider (service provider) provided and maintained.
SaaS – Software as a Service in Cloud computing – Cloud computing offer access using collections of software and application programs. SaaS service providers offer special selections of software running on their infrastructure. SaaS is also known as software on demand (software as needed).
Representation of cloud computing delivery models
It also includes the definition of the National Institute of Standards and Technology (NIST) has four delivery models:
Public Cloud Computing – public Cloud Computing – provides abstracted access to IT infrastructure for the general public via the Internet. Public Cloud Computing service providers allow their customers to rent IT infrastructure on a flexible basis of paying for the actual utilization or consumption (pay-as-you-go), without having to invest capital in computing and data center infrastructure.
Private Cloud Computing – the private Cloud Computing provides abstracted access to IT infrastructure within the organization (agency, company, start-up, club), such as Ubuntu One .
Hybrid Cloud Computing – the cloud of hybrid computers – offering access to abstract combined IT infrastructure in the areas of public clouds and private clouds, to meet the needs of their users.
Community Cloud Computing – provides abstracted access to IT infrastructure as the public cloud – but for a smaller group of users who are mostly distributed locally, shares the costs (for example, several municipal governments, universities, business / corporate with similar interests, research communities).
And lists five essential characteristics of cloud computing:
Self-assignment of benefits from the cloud or by the user, which will be available when needed (self-service provisioning / As-needed availability).
Scalability by decoupling the use of swings and infrastructure limitations (scalability).
Reliability and fault tolerance guarantees permanently defined quality standards of the IT infrastructure for the user (Reliability and fault-tolerance).
Optimization and consolidation, efficiency and economy in adapting to continuous environmental protection standards, which can be optimized successively by the cloud service provider (Optimization / Consolidation).
Quality assurance and quality control can be continuously monitored by the service provider and ensure that no users are burdened must (QoS – Quality of Service).
Advantages and problems
Local resources (software and hardware) can be saved in Cloud Computing. Increasingly, these resource efficiency is also related to the sustainable use of ICT systems. A frequently cited example of the implementation of e-mail systems based on “cloud computing” is, as here, the complexity of the application by taking measures for prevention, so that smaller companies can benefit from outsourcing of Cloud Computing. There are also advantages in the case of strongly fluctuating demand: Normally, you would have to hold enough capacity to handle the load peaks. When using “cloud computing” is the unused capacity can be variably adjusted to the actual demand in the short term.
The basic problem, namely the protection of access to the application data during transfer between local client and remote server could not be solved satisfactorily to date. There are however a number of developments in the field of data security such as SSL / TLS encryption . An overview of the problems of data security and data protection in the public cloud computing give the state of the art in January 2011 by Jansen and Grance by NIST.