CLOUD COMPUTING TECHNOLOGY

A TECHNICAL SEMINAR REPORT

Submitted in partial fulfillment of the requirementsfor the award of the degree of

MASTER OF COMPUTER APPLICATIONSubmitted by

B. K.ASHOK KUMARReg:122H1F0002

Under the Supervision of

Mr.E.RAMESH REDDY., M.Tech

Assistant Professor, Dept of MCA

DEPARTMENT OF MASTER OF COMPUTER APPLICATION

AUDISANKARA INSTITUTE OF TECHNOLOGY, GUDURSPSR Nellore District, AP. Jawaharlal Nehru Technological University, Anantapuramu, AP, India

MAY 2015

AUDISANKARA INSTITUTE OF TECHNOLOGYGUDURBONAFIDE CERTIFICATE

Certified that this seminar report Google loon is the bonafide work done by P.Surendra (122h1f0028) who carried out the work under my supervision during the year 2014 - 2015 towards partial fulfillment of the requirements of the Degree of Master of Computer Application from Jawaharlal Nehru Technological University, Anantapuramu. The results embodied in this report have not been submitted to any other University for the award of any degree.

Table Of Contents

Abstract1. Introduction. 62. Cloud computing The Concept 83. History... 124. Need For Cloud Computing.. 145. Key Characteristics... 166. Components.. 187. Architecture...... 218. Types 229. Roles. 2310. Advantages... 24Disadvantages... 2711. Conclusion 29

Abstract

Computers have become an indispensable part of life. We needcomputers everywhere, be it for work, research or in any such field. As the use of computers in our day-to-day life increases, the computing resources that we need also go up. For companies like Google and Microsoft, harnessing the resources as and when they need it is not a problem. But when it comes to smaller enterprises, affordability becomes a huge factor. With the huge infrastructure come problems like machines failure, hard drive crashes, software bugs, etc. This might be a big headache for such a community. CloudComputing offers a solution to this situation.

Cloud computing is a paradigm shift in which computing is moved away from personal computers and even the individual enterprise application server to a cloud of computers. A cloud is a virtualized server pool which can provide the different computing resources of their clients. Users of this system need only be concerned with the computing service being asked for. The underlying details of how it is achieved are hidden from the user. The data and the services provided reside in massively scalable data centers and can be ubiquitously accessed from any connected device all over the world.

Cloud computing is the style of computing where massively scaled IT related capabilities are provided as a service across the internet to multiple external customers and are billed by consumption. Many cloud computing providers have popped up and there is a considerable growth in the usage of this service. Google, Microsoft, Yahoo, IBM and Amazon have started providing cloud computing services. Amazon is the pioneer in this field. Smaller companies like SmugMug, which is an online photo hosting site, has used cloud services for the storing all the data and doing some of its services.

Cloud Computing is finding use in various areas like web hosting, parallel batch processing, graphics rendering, financial modeling, web crawling, genomics analysis, etc.

1. Introduction

The Greek myths tell of creatures plucked from the surface of the Earth andenshrined as constellations in the night sky. Something similar is happening today in the world of computing. Data and programs are being swept up from desktop PCs and corporate server rooms and installed in the compute cloud. In general, there is a shift in the geography of computation.

What is cloud computing exactly? As a beginning here is a definition

An emerging computer paradigm where data and servicesreside in massively scalable data centers in the cloud andcan be accessed from any connected devices over theinternet

Like other definitions of topics like these, an understanding of the term cloudcomputing requires an understanding of various other terms which are closely related to this. While there is a lack of precise scientific definitions for many of these terms, general definitions can be given.

Cloud computing is an emerging paradigm in the computer industry where thecomputing is moved to a cloud of computers. It has become one of the buzz words of the industry. The core concept of cloud computing is, quite simply, that the vast computing resources that we need will reside somewhere out there in the cloud of computers and well connect to them and use them as and when needed.

Computing can be described as any activity of using and/or developingcomputer hardware and software. It includes everything that sits in the bottom layer, i.e. everything from raw compute power to storage capabilities. Cloud computing ties together all these entities and delivers them as a single integrated entity under its own sophisticated management.

Cloud is a term used as a metaphor for the wide area networks (like internet)or any such large networked environment. It came partly from the cloud-like symbol used to represent the complexities of the networks in the schematic diagrams. It represents all the complexities of the network which may include everything from cables, routers, servers, data centres and all such other devices.

Computing started off with the mainframe era. There were big mainframes andeveryone connected to them via dumb terminals. This old model of businesscomputing was frustrating for the people sitting at the dumb terminals because they could do only what they were authorized to do. They were dependent on the computer administrators to give them permission or to fix their problems. They had no way of staying up to the latest innovations.

The personal computer was a rebellion against the tyranny of centralizedcomputing operations. There was a kind of freedom in the use of personal computers. But this was later replaced by server architectures with enterprise servers and others showing up in the industry. This made sure that the computing was done and it did not eat up any of the resources that one had with him. All the computing was performed at servers. Internet grew in the lap of these servers. With cloud computing we have come a full circle. We come back to the centralized computing infrastructure. But this time it is something which can easily be accessed via the internet and something over which we have all the control.

2. Cloud computing- The Concept

Cloud computing is Internet ("cloud") based development and use of computer technology ("computing"). It is a style of computing in which dynamically scalable and often virtualized resources are provided as a service over the Internet. Users need not have knowledge of, expertise in, or control over the technology infrastructure "in the cloud" that supports them.The concept incorporates infrastructure as a service (IaaS), platform as a service (PaaS) and software as a service (SaaS) as well as Web 2.0 and other recent technology trends which have the common theme of reliance on the Internet for satisfying the computing needs of the users. Examples of SaaS vendors include Salesforce.com and Google Apps which provide common business applications online that are accessed from a web browser, while the software and data are stored on the servers.The term cloud is used as a metaphor for the Internet, based on how the Internet is depicted in computer network diagrams, and is an abstraction for the complex infrastructure it conceals.

2.1 Comparison:Cloud computing is often confused with grid computing ("a form of distributed computing whereby a 'super and virtual computer' is composed of a cluster of networked, loosely-coupled computers, acting in concert to perform very large tasks"), utility computing (the "packaging of computing resources, such as computation and storage, as a metered service similar to a traditional public utility such as electricity") and autonomic computing ("computer systems capable of self-management").Indeed many cloud computing deployments as of 2009[update] depend on grids, have autonomic characteristics and bill like utilities but cloud computing can be seen as a natural next step from the grid-utility model. Some successful cloud architectures have little or no centralized infrastructure or billing systems whatsoever, including peer-to-peer networks like Bit Torrent and Skype and volunteer computing like

2.2 Implementation:The majority of cloud computing infrastructure as of 2009[update] consists of reliable services delivered through data centers and built on servers with different levels of virtualization technologies. The services are accessible anywhere that has access to networking infrastructure. The Cloud appears as a single point of access for all the computing needs of consumers. Commercial offerings need to meet the quality of service requirements of customers and typically offer service level agreements. Open standards are critical to the growth of cloud computing and open source software has provided the foundation for many cloud computing implementations.2.3 Characteristics:As customers generally do not own the infrastructure, they merely access or rent, they can avoid capital expenditure and consume resources as a service, paying instead for what they use. Many cloud-computing offerings have adopted the utility computing model, which is analogous to how traditional utilities like electricity are consumed, while others are billed on a subscription basis. Sharing "perishable and intangible" computing power among multiple tenants can improve utilization rates, as servers are not left idle, which can reduce costs significantly while increasing the speed of application development. A side effect of this approach is that "computer capacity rises dramatically" as customers do not have to engineer for peak loads. Adoption has been enabled by "increased high-speed bandwidth" which makes it possible to receive the same response times from centralized infrastructure at other sites.2.4 Economics:Cloud computing users can avoid capital expenditure (CapEx) on hardware, software and services, rather paying a provider only for what they use. Consumption is billed on a utility (e.g. resources consumed, like electricity) or subscription (e.g. time based, like a newspaper) basis with little or no upfront cost. Other benefits of this time sharing style approach are low barriers to entry, shared infrastructure and costs, low management overhead and immediate access to a broad range of applications. Users can generally terminate the contract at any time (thereby avoiding return on investment risk and uncertainty) and the services are often covered by service level agreements with financial penalties.According to Nicholas Carr the strategic importance of information technology is diminishing as it becomes standardized and cheaper. He argues that the cloud computing paradigm shift is similar to the displacement of electricity generators by electricity grids early in the 20th century.

2.5 Companies:Providers including Amazon, Microsoft, Google, Sun and Yahoo exemplify the use of cloud computing. It is being adopted by individual users through large enterprises including General Electric, L'Oral, and Procter & Gamble.

3. HistoryThe Cloud is a term with a long history in telephony, which has in the past decade, been adopted as a metaphor for internet based services, with a common depiction in network diagrams as a cloud outline.The underlying concept dates back to 1960 when John McCarthy opined that "computation may someday be organized as a public utility"; indeed it shares characteristics with service bureaus which date back to the 1960s. The term cloud had already come into commercial use in the early 1990s to refer to large ATM networks. By the turn of the 21st century, the term "cloud computing" had started to appear, although most of the focus at this time was on Software as a service (SaaS).In 1999, Salesforce.com was established by Marc Benioff, Parker Harris, and his fellows. They applied many technologies of consumer web sites like Google and Yahoo! to business applications. They also provided the concept of "On demand" and "SaaS" with their real business and successful customers. The key for SaaS is being customizable by customer alone or with a small amount of help. Flexibility and speed for application development have been drastically welcomed and accepted by business users.IBM extended these concepts in 2001, as detailed in the Autonomic Computing Manifesto -- which described advanced automation techniques such as self-monitoring, self-healing, self-configuring, and self-optimizing in the management of complex IT systems with heterogeneous storage, servers, applications, networks, security mechanisms, and other system elements that can be virtualized across an enterprise.Amazon.com played a key role in the development of cloud computing by modernizing their data centers after the dot-com bubble and, having found that the new cloud architecture resulted in significant internal efficiency improvements, providing access to their systems by way of Amazon Web Services in 2005 on a utility computing basis.2007 saw increased activity, with Google, IBM, and a number of universities embarking on a large scale cloud computing research project, around the time the term started gaining popularity in the mainstream press. It was a hot topic by mid-2008 and numerous cloud computing events had been scheduled.In August 2008, Gartner Research observed that "organizations are switching from company-owned hardware and software assets to per-use service-based models" and that the "projected shift to cloud computing will result in dramatic growth in IT products in some areas and in significant reductions in other areas."

4. Need for Cloud Computing

What could we do with 1000 times more data and CPU power? One simplequestion. Thats all it took the interviewers to bewilder the confident job applicants at Google. This is a question of relevance because the amount of data that an application handles is increasing day by day and so is the CPU power that one can harness.

There are many answers to this question. With this much CPU power, wecould scale our businesses to 1000 times more users. Right now we are gathering statistics about every user using an application. With such CPU power at hand, we could monitor every single user click and every user interaction such that we can gather all the statistics about the user. We could improve the recommendation systems of users. We could model better price plan choices. With this CPU power we couldsimulate the case where we have say 1,00,000 users in the system without any glitches.

There are lots of other things we could do with so much CPU power and datacapabilities. But what is keeping us back. One of the reasons is the large scalearchitecture which comes with these are difficult to manage. There may be many different problems with the architecture we have to support. The machines may start failing, the hard drives may crash, the network may go down and many other such hardware problems. The hardware has to be designed such that the architecture is reliable and scalable. This large scale architecture has a very expensive upfront and has high maintenance costs. It requires different resources like machines, power, cooling, etc. The system also cannot scale as and when needed and so is not easily reconfigurable.

The resources are also constrained by the resources. As the applicationsbecome large, they become I/O bound. The hard drive access speed becomes alimiting factor. Though the raw CPU power available may not be a factor, the amount of RAM available clearly becomes a factor. This is also limited in this context. If at all the hardware problems are managed very well, there arises the software problems. There may be bugs in the software using this much of data. The workload also demands two important tasks for two completely different people. The software has to be such that it is bug free and has good data processing algorithms to manage all thedata.The cloud computing works on the cloud - so there are large groups of oftenlow-cost servers with specialized connections to spread the data-processing chores among them. Since there are a lot of low-cost servers connected together, there are large pools of resources available. So these offer almost unlimited computing resources. This makes the availability of resources a lesser issue.

The data of the application can also be stored in the cloud. Storage of data inthe cloud has many distinct advantages over other storages. One thing is that data is spread evenly through the cloud in such a way that there are multiple copies of the data and there are ways by which failure can be detected and the data can be rebalanced on the fly. The I/O operations become simpler in the cloud such that browsing and searching for something in 25GB or more of data becomes simpler in the cloud, which is nearly impossible to do on a desktop.

The cloud computing applications also provide automatic reconfiguration ofthe resources based on the service level agreements. When we are using applications out of the cloud, to scale the application with respect to the load is a mundane task because the resources have to be gathered and then provided to the users. If the load on the application is such that it is present only for a small amount of time as compared to the time its working out of the load, but occurs frequently, then scaling of the resources becomes tedious. But when the application is in the cloud, the load can be managed by spreading it to other available nodes by making a copy of the application on to them. This can be reverted once the load goes down. It can be done as and when needed. All these are done automatically such that the resources maintain and manage themselves.

5. Key Characteristics Cost is greatly reduced and capital expenditure is converted to operational expenditure. This lowers barriers to entry, as infrastructure is typically provided by a third-party and does not need to be purchased for one-time or infrequent intensive computing tasks. Pricing on a utility computing basis is fine-grained with usage-based options and minimal or no IT skills are required for implementation.

Device and location independence enable users to access systems using a web browser regardless of their location or what device they are using, e.g., PC, mobile. As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet the users can connect from anywhere.

Multi-tenancy enables sharing of resources and costs among a large pool of users, allowing for: Centralization of infrastructure in areas with lower costs (such as real estate, electricity, etc.) Peak-load capacity increases (users need not engineer for highest possible load-levels) Utilization and efficiency improvements for systems that are often only 10-20% utilized. Reliability improves through the use of multiple redundant sites, which makes it suitable for business continuity and disaster recovery. Nonetheless, most major cloud computing services have suffered outages and IT and business managers are able to do little when they are affected.

Scalability via dynamic ("on-demand") provisioning of resources on a fine-grained, self-service basis near real-time, without users having to engineer for peak loads. Performance is monitored and consistent and loosely-coupled architectures are constructed using web services as the system interface.

Security typically improves due to centralization of data, increased security-focused resources, etc., but raises concerns about loss of control over certain sensitive data. Security is often as good as or better than traditional systems, in part because providers are able to devote resources to solving security issues that many customers cannot afford. Providers typically log accesses, but accessing the audit logs themselves can be difficult or impossible.

Sustainability comes about through improved resource utilization, more efficient systems, and carbon neutrality. Nonetheless, computers and associated infrastructure are major consumers of energy. 6. Components

Cloud computing Components

ApplicationsFacebookGoogle AppsSalesForceMicrosoft Online

ClientBrowser(Chrome)FirefoxCloudMobile (AndroidiPhone)Netbook (EeePCMSI Wind)Nettop (CherryPalZonbu)

InfrastructureBitTorrentEC2GoGridSun Grid3tera

PlatformsApp EngineAzureMossoSalesForce

ServicesAlexaFPSMTurkSQS

StorageS3SimpleDBSQL Services

StandardsAjaxAtomHTML 5REST

6.1 ApplicationA cloud application leverages the Cloud in software architecture, often eliminating the need to install and run the application on the customer's own computer, thus alleviating the burden of software maintenance, ongoing operation, and support. For example: Peer-to-peer / volunteer computing (Bittorrent, BOINC Projects, Skype) Web application (Facebook) Software as a service (Google Apps, SAP and Salesforce) Software plus services (Microsoft Online Services)6.2ClientA cloud client consists of computer hardware and/or computer software which relies on cloud computing for application delivery, or which is specifically designed for delivery of cloud services and which, in either case, is essentially useless without it. For example: Mobile (Android, iPhone, Windows Mobile) Thin client (CherryPal, Zonbu, gOS-based systems) Thick client / Web browser (Google Chrome, Mozilla Firefox)6.3 InfrastructureCloud infrastructure, such as Infrastructure as a service, is the delivery of computer infrastructure, typically a platform virtualization environment, as a service. For example: Full virtualization (GoGrid, Skytap) Management (RightScale) Compute (Amazon Elastic Compute Cloud) Platform (Force.com) 6.4 PlatformA cloud platform, such as Platform as a service, the delivery of a computing platform, and/or solution stack as a service, facilitates deployment of applications without the cost and complexity of buying and managing the underlying hardware and software layers. For example: Web application frameworks Python Django (Google App Engine) Ruby on Rails (Heroku) .NET (Azure Services Platform) Web hosting (Mosso) Proprietary (Force.com)6.5 ServiceA cloud service includes "products, services and solutions that are delivered and consumed in real-time over the Internet". For example, Web Services ("software system[s] designed to support interoperable machine-to-machine interaction over a network") which may be accessed by other cloud computing components, software, e.g., Software plus service, or end users directly. Specific examples include: Identity (OAuth, OpenID) Integration (Amazon Simple Queue Service) Payments (Amazon Flexible Payments Service, Google Checkout, PayPal) Mapping (Google Maps, Yahoo! Maps) Search (Alexa, Google Custom Search, Yahoo! BOSS) Others (Amazon Mechanical Turk)

6.6 StorageCloud storage involves the delivery of data storage as a service, including database-like services, often billed on a utility computing basis, e.g., per gigabyte per month. For example: Database (Amazon SimpleDB, Google App Engine's BigTable datastore) Network attached storage (MobileMe iDisk, Nirvanix CloudNAS) Synchronization (Live Mesh Live Desktop component, MobileMe push functions) Web service (Amazon Simple Storage Service, Nirvanix SDN)

7. Architecture

Cloud architecture, the systems architecture of the software systems involved in the delivery of cloud computing, comprises hardware and software designed by a cloud architect who typically works for a cloud integrator. It typically involves multiple cloud components communicating with each other over application programming interfaces, usually web services.This closely resembles the UNIX philosophy of having multiple programs doing one thing well and working together over universal interfaces. Complexity is controlled and the resulting systems are more manageable than their monolithic counterparts.Cloud architecture extends to the client, where web browsers and/or software applications access cloud applications.Cloud storage architecture is loosely coupled, where metadata operations are centralized enabling the data nodes to scale into the hundreds, each independently delivering data to applications or user.

8. Types

8.1Public cloudPublic cloud or external cloud describes cloud computing in the traditional mainstream sense, whereby resources are dynamically provisioned on a fine-grained, self-service basis over the Internet, via web applications/web services, from an off-site third-party provider who shares resources and bills on a fine-grained utility computing basis.8.2Private cloudPrivate cloud and internal cloud are neologisms that some vendors have recently used to describe offerings that emulate cloud computing on private networks. These products claim to "deliver some benefits of cloud computing without the pitfalls", capitalizing on data security, corporate governance, and reliability concerns. While an analyst predicted in 2008 that private cloud networks would be the future of corporate IT, there is some uncertainty whether they are a reality even within the same firm. Analysts also claim that within five years a "huge percentage" of small and medium enterprises will get most of their computing resources from external cloud computing providers as they "will not have economies of scale to make it worth staying in the IT business" or be able to afford private clouds.The term has also been used in the logical rather than physical sense, for example in reference to platform as service offerings, though such offerings including Microsoft's Azure Services Platform are not available for on-premises deployment.8.3Hybrid cloudA hybrid cloud environment consisting of multiple internal and/or external providers"will be typical for most enterprises".

9. Roles

9.1ProviderA cloud computing provider or cloud computing service provider owns and operates live cloud computing systems to deliver service to third parties. The barrier to entry is also significantly higher with capital expenditure required and billing and management creates some overhead. Nonetheless, significant operational efficiency and agility advantages can be realized, even by small organizations, and server consolidation and virtualization rollouts are already well underway. Amazon.com was the first such provider, modernizing its data centers which, like most computer networks, were using as little as 10% of its capacity at any one time just to leave room for occasional spikes. This allowed small, fast-moving groups to add new features faster and easier, and they went on to open it up to outsiders as Amazon Web Services in 2002 on a utility computing basis.9.2UserA user is a consumer of cloud computing. The privacy of users in cloud computing has become of increasing concern. The rights of users are also an issue, which is being addressed via a community effort to create a bill of rights.9.3VendorA vendor sells products and services that facilitate the delivery, adoption and use of cloud computing.For example: Computer hardware (Dell, HP, IBM, Sun Microsystems) Storage (Sun Microsystems, EMC, IBM) Infrastructure (Cisco Systems) Computer software (3tera, Hadoop, IBM, RightScale) Operating systems (Solaris, AIX, Linux including Red Hat) Platform virtualization (Citrix, Microsoft, VMware, Sun xVM, IBM)

10. Advantages

Lower computer costs: You do not need a high-powered and high-priced computer to run cloud computing's web-based applications. Since applications run in the cloud, not on the desktop PC, your desktop PC does not need the processing power or hard disk space demanded by traditional desktop software. When you are using web-based applications, your PC can be less expensive, with a smaller hard disk, less memory, more efficient processor... In fact, your PC in this scenario does not even need a CD or DVD drive, as no software programs have to be loaded and no document files need to be saved.

Improved performance: With few large programs hogging your computer's memory, you will see better performance from your PC. Computers in a cloud computing system boot and run faster because they have fewer programs and processes loaded into memory.

Reduced software costs: Instead of purchasing expensive software applications, you can get most of what you need for free-ish! most cloud computing applications today, such as the Google Docs suite. better than paying for similar commercial software which alone may be justification for switching to cloud applications.

Instant software updates: Another advantage to cloud computing is that you are no longer faced with choosing between obsolete software and high upgrade costs. When the application is web-based, updates happen automatically available the next time you log into the cloud. When you access a web-based application, you get the latest version without needing to pay for or download an upgrade.

Improved document format compatibility: You do not have to worry about the documents you create on your machine being compatible with other users' applications or OSes There are potentially no format incompatibilities when everyone is sharing documents and applications in the cloud.

Unlimited storage capacity: Cloud computing offers virtually limitless storage. Your computer's current 1 Tbyte hard drive is small compared to the hundreds of Pbytes available in the cloud.

Increased data reliability: Unlike desktop computing, in which if a hard disk crashes and destroy all your valuable data, a computer crashing in the cloud should not affect the storage of your data. if your personal computer crashes, all your data is still out there in the cloud, still accessible In a world where few individual desktop PC users back up their data on a regular basis, cloud computing is a data-safe computing platform!

Universal document access: That is not a problem with cloud computing, because you do not take your documents with you. Instead, they stay in the cloud, and you can access them whenever you have a computer and an Internet connection Documents are instantly available from wherever you are

Latest version availability: When you edit a document at home, that edited version is what you see when you access the document at work. The cloud always hosts the latest version of your documents

Easier group collaboration: Sharing documents leads directly to better collaboration. Many users do this as it is an important advantages of cloud computing multiple users can collaborate easily on documents and projects

Device independence: You are no longer tethered to a single computer or network. Changes to computers, applications and documents follow you through the cloud. Move to a portable device, and your applications and documents are still available.

11. Disadvantages

Requires a constant Internet connection: Cloud computing is impossible if you cannot connect to the Internet. Since you use the Internet to connect to both your applications and documents, if you do not have an Internet connection you cannot access anything, even your own documents. A dead Internet connection means no work and in areas where Internet connections are few or inherently unreliable, this could be a deal-breaker.

Does not work well with low-speed connections: Similarly, a low-speed Internet connection, such as that found with dial-up services, makes cloud computing painful at best and often impossible. Web-based applications require a lot of bandwidth to download, as do large documents.

Features might be limited: This situation is bound to change, but today many web-based applications simply are not as full-featured as their desktop-based applications.

Can be slow: Even with a fast connection, web-based applications can sometimes be slower than accessing a similar software program on your desktop PC. Everything about the program, from the interface to the current document, has to be sent back and forth from your computer to the computers in the cloud. If the cloud servers happen to be backed up at that moment, or if the Internet is having a slow day, you would not get the instantaneous access you might expect from desktop applications.

Stored data might not be secure: With cloud computing, all your data is stored on the cloud. The questions is How secure is the cloud? Can unauthorised users gain access to your confidential data?

Stored data can be lost: Theoretically, data stored in the cloud is safe, replicated across multiple machines. But on the off chance that your data goes missing, you have no physical or local backup.

12. ConclusionCloud Computing Brings Possibilities.. Increases business responsiveness Accelerates creation of new services via rapid prototyping capabilities Reduces acquisition complexity via service oriented approach Uses IT resources efficiently via sharing and higher system utilization Reduces energy consumption Handles new and emerging workloads Scales to extreme workloads quickly and easily Simplifies IT management Platform for collaboration and innovation Cultivates skills for next generation workforceToday, with such cloud-based interconnection seldom in evidence, cloud computing might be more accurately described as "sky computing," with many isolated clouds of services which IT customers must plug into individually. On the other hand, as virtualization and SOA permeate the enterprise, the idea of loosely coupled services running on an agile, scalable infrastructure should eventually make every enterprise a node in the cloud. It's a long-running trend with a far-out horizon. But among big metatrends, cloud computing is the hardest one to argue with in the long term. Cloud Computing is a technology which took the software and business world by storm. The much deserved hype over it will continue for years to come.