CLOUD COMPUTING by tpradeepgtl


									A paper on   Cloud computing

      D.R.MANOGNA                                             K.RAMYA

     CSE II YEAR                                          CSE II YEAR

ABSTRACT                                                 Cloud computing also describes applications that are
                                                         extended to be accessible through the Internet. These
This paper describes cloud computing, a computing        cloud applications use large data centers and
platform for the next generation of the Internet. The    powerful servers that host Web applications and Web
paper defines clouds, explains the business benefits     services. Anyone with a suitable Internet connection
of cloud computing, and outlines cloud architecture      and a standard browser can access a cloud
and its major components.                                application.

Cloud computing is Internet based development and
use of computer technology, whereby dynamically
                                                         A cloud is a pool of virtualized computer resources.
scalable virtualised resources are provided “services
                                                         A cloud can: Host a variety of different workloads,
over the internet. Users need not have knowledge of,
                                                         including batch-style back-end jobs and interactive,
expertise in, or control over the technology
                                                         user-facing applications. Allow workloads to be
infrastructure that supports them. The concept
                                                         deployed and scaled-out quickly through the rapid
incorporates software as a service (SaaS), Web 2.0
                                                         provisioning    of   virtual   machines     or   physical
and other recent, well-known technology trends, in
                                                         machines, that allow Support redundant, self-
which the common theme is reliance on the Internet
                                                         recovering, highly scalable programming models that
for satisfying the computing needs of the users. An
                                                         allow workloads to recover from many unavoidable
often-quoted example is Google Apps, which
                                                         hardware/software failures. Monitor resource use in
provides common business applications online that
                                                         real time to enable rebalancing of allocations when
are accessed from a web browser, while the software
                                                         needed. Cloud computing environments support grid
and data are stored on Google servers. The cloud is a
                                                         computing by quickly providing physical and virtual
metaphor for the Internet, based on how it is depicted
                                                         servers on which the grid applications can run. Cloud
in computer network diagrams, and is an abstraction
                                                         computing should not be confused with grid
for the complex infrastructure it conceals
                                                         computing. Grid computing involves dividing a large
                                                         task into many smaller tasks that run in parallel on
                                                         separate servers. Grids require many computers,

What is a cloud?                                         typically in the thousands, and commonly use

Cloud is a term used to describe both a platform and     servers, desktops, and laptops. Clouds also support

type of application. A cloud Computing platform          nongrid environments, such as a three-tier Web

dynamically provisions, configures, reconfigures, and    architecture    running    standard    or    Web      2.0

deprovisions servers as needed. Servers in the cloud     applications. A cloud is more than a collection of

can be physical machines or virtual machines.            computer resources because a cloud provides a

Advanced clouds typically include other computing        mechanism to manage those resources. Management

resources such as storage area networks (SANs),          includes provisioning, change requests, reimaging,

network equipment, firewall and other security           workload       rebalancing,     deprovisioning,      and

devices.                                                 monitoring.
                                                           consumption basis (giving rise to other common
What is a cloud platform?                                  phrases such as ‘utility computing’ and ‘platforms- a-
The coming shift to cloud computing is a major             service’). More significantly, Cloud computing is the
change in our industry. One of the most important          next “turn of the crank” in IT data center paradigms.
parts of that shift is the advent of cloud platforms. As   IT data center managers have been put to the test
its name suggests, this kind of platform lets              over the years, being asked to respond to in-sourcing
developers write applications that run in the cloud, or    (remember when timesharing was the only game in
use services provided from the cloud, or both.             1970), glass-house build-up (in the 1980s), server-
Different names are used for this kind of platform         room build-out (in the 1990s), datacenter out-
today, including on-demand platform and platform as        sourcing (the shift in the 2000s), virtualization and
a service (PaaS). Whatever it’s called, this new way       server consolidation (today). Cloud computing
of supporting applications has great potential. To see     combines the best of infrastructure utility out-
why, think about how application platforms are used        sourcing with the IT control of in-sourcing and the
today. When a development team creates an                  lower-cost advantages of server consolidation. Cloud
on-premises application (i.e., one that will run within    computing is often associated with new Web 2.0
an organization), much of what that application needs      start-up   companies.    The   best   known     Cloud
already exists. An operating system provides basic         application is the Google search engine that, while
support for executing the application, interacting with    consuming huge amounts of processing power, never
storage, and more, while other computers in the            needs to rely on database ACID rules or two-phase
environment offer services such as remote storage. If      commits. Amazon’s Elastic Compute Cloud hosts
the creators of every on-premises application first had    start-up companies that provide photo sharing, phone
to build all of these basics, we’d have many fewer         text message collection and redistribution services,
applications today. Similarly, if every development        and social networking and collaboration. These
team that wishes to create a cloud application must        relatively simple applications built from scratch using
first build its own cloud platform, we won’t see many      languages such as Python or Ruby need not adhere to
cloud applications. Fortunately, vendors are rising to     the critical uptime requirements of a traditional data
this challenge, and a number of cloud platform             center processing payroll or controlling inventory.
technologies are available today. The goal of this         Nevertheless,   Cloud     computing     is   extremely
overview is to categorize and briefly describe those       attractive to traditional IT in the way that it can
technologies as they’re seen by someone who creates        convert the consumptive model of IT resources from
enterprise.                                                a capital expenditure model to an operational
                                                           expenditure model. Instead of building out on-
It has become more usefully characterized as a style       premises datacenters, Cloud offers the ability to soak
of computing where massively scalable IT-enabled           up excess compute capacity wherever it may lie.
capabilities are provided “as a service” to multiple       After all, it is always 3am somewhere in the world
customers. Unlike previous IT licensing models,            and finding and using that capacity, thanks to high
however, these ‘services’ are typically billed on a        speed network infrastructure, can be very cost
effective. Of course, the consumptive model of            Microsoft Windows and Linux operating systems,
controlling costs offered by Cloud computing is           along with the installation / configuration of any
nothing new to IBM data center managers, and many         software stack that the user requests. Tivoli
of the significant trends we are witnessing in the        Provisioning Manager uses Websphere Application
industry today have some very interesting parallels       Server to communicate the provisioning status and
and precedents in traditional data center evolution.      availability of resources in the data center, to
                                                          schedule the provisioning and deprovisioning of
                                                          resources, and to reserve resources for future use. As
                                                          a result of the provisioning, virtual machines are

The majority of cloud computing infrastructure as of      created using the XEN hypervisor or physical
                                                          machines are created using Network Installation
2009 consists of reliable services delivered through
                                                          Manager, Remote Deployment Manager, or Cluster
data centers and built on servers with different levels
                                                          Systems Manager, depending upon the operating
of virtualization technologies. The services are
accessible anywhere in the world, with The Cloud          system and platform. IBM Tivoli Monitoring Server
                                                          monitors the health (CPU, disk, and memory) of the
appearing as a single point of access for all the
                                                          servers provisioned by Tivoli Provisioning Manager.
computing     needs   of    consumers.    Commercial
offerings need to meet the quality of service
requirements of customers and typically offer service     DB2 is the database server that Tivoli Provisioning
                                                          Manager uses to store the resource data. IBM Tivoli
level agreements, Open standards and open source
                                                          Monitoring agents that are installed on the virtual and
software are also critical to the growth of cloud
computing.                                                physical machines communicate with the Tivoli
                                                          Monitoring server to get the health of the virtual
                                                          machines and provide the same to the user. The cloud
                                                          computing platform has two user interfaces to
                                                                                One interface is feature rich --
                                                          fully loaded with the WebSphere suite of products –
                                                          and relatively more involved from a process
                                                          perspective. For more information on this interface,

                                                          provisioning requests. All requests are handled by
                                                          Web2.0 components deployed on the WebSphere
                                                          Application Server.

Tivoli Provisioning Manager automates imaging,
deployment, installation, and configuration of the
.                                                           Cloud platforms: A cloud platform provides cloud-
                                                            based services for creating applications. Rather than
                                                            building their own custom foundation, for example,
                                                            the creators of a new SaaS application could instead
                                                            build on a cloud platform. As the Figure shows, the
                                                            direct users of a cloud platform are developers, not
                                                            end users.

                                                            foundation: Nearly every application uses some
                                                            platform software on the machine it runs on. This
                                                            typically includes various support functions, such as
                                                            standard libraries and storage, and a base operating

                                                            A group of infrastructure services: In a modern
                                                            distributed environment, applications frequently use
Software as a service (SaaS): A SaaS application            basic services provided on other computers. It’s
runs entirely in the cloud (that is, on servers at an       common to provide remote storage, for example,
Internet-accessible    service    provider).   The    on-   integration services, an identity service, and more.
premises client is typically a browser or some other
simple client. The most well-known example of a             A set of application services: As more and more
SaaS application today is probably                          applications become service-oriented, the functions, but many, many others are also              they offer become accessible to new applications.
available.                                                  Even though these applications exist primarily to
Attached services: Every on-premises application            provide services to end users, this also makes them
provides useful functions on its own. An application        part of the application platform. (It might seem odd
can   sometimes       enhance    these   by    accessing    to think of other applications as part of the platform,
application-specific services provided in the cloud.        but in a service-oriented world, they certainly are.)
Because these services are usable only by this              And while they’re not shown in Figure 2,
particular application, they can be thought of as           development tools are another important part of this
attached to it. One popular consumer example of this        story. Modern tools can help developers build
is Apple’s iTunes: The desktop application is useful        applications using all three parts of an application
for playing music and more, while an attached               platform. To make this abstract model more concrete,
service allows buying new audio and video content.          think about how it fits with today’s most popular on
Microsoft’s Exchange Hosted Services provides an            premises Platforms. The on-premises foundation
enterprise   example,    adding     cloud-based      spam   looks like this:
filtering, archiving, and other services to an on-
premises Exchange server.
Operating system:                                          Microsoft SQL Server, and IBM DB2. For on-
From a platform point of view, an operating system         premises infrastructure services, typical examples
provides a set of basic interfaces for applications to     include the following:
use. By far the most well-known example of an
operating system in the cloud today is Amazon’s
Elastic Compute Cloud (EC2). EC2 provides
customer-specific Linux instances running in virtual
machines (VMs). From a technical perspective, it
might be more accurate to think of EC2 as a platform
for VMs rather than operating systems. Still, a
developer sees an operating system interface, and so
viewing it in this light makes more sense here.
Each development team is free to use whatever local
support it likes in this VM—Amazon doesn’t care.
The creators of one application might choose a Java
EE app server and MySQL, for example, while
another group might go with Ruby on Rails. EC2
customers are even free to create many Linux
instances, then distribute large workloads across them
in parallel, such as for scientific applications. While
the service EC2 provides is quite basic, it’s also very
general, and so it can be used in many different ways.     Storage:    Like      storage   in   the   foundation,
                                                           infrastructure storage comes in various styles. A
Local support: Different technologies are used             remote file system might provide simple byte-
depending on the style of application. The .NET            oriented storage, while a Microsoft SharePoint
Framework and Java EE application servers provide          document library provides a more structured remote
general support for Web applications and more, for         storage service. Applications can also access a
instance, while other technologies target specific         database system remotely, allowing access to another
kinds of applications. For example, Microsoft’s            kind of structured storage.
Dynamics     CRM     product    includes    a   platform
designed for creating a particular type of business        Integration: Connecting applications within an
application. Similarly, different kinds of storage are     organization usually depends on a remote service
used for different purposes. Raw byte storage is           provided by some integration product. A message
provided by the file systems in Windows, Linux, and        queue is a simple example of this, while more
other operating systems, while more structured             complex scenarios use products such as IBM’s
storage is provided by a range of database                 WebSphere Process Server, Microsoft’s BizTalk
technologies, including the Oracle DBMS, MySQL,            Server, and others.
                                                            evolution is clear: providing cloud versions of all
Identity:     Providing   identity   information   is   a   three.
fundamental requirement for most distributed
applications. Common on-premises technologies that
address this include Microsoft’s Active Directory and
other   LDAP       servers.   On-premises    application
services, the third category shown in Figure 2, vary
widely across different organizations. The reason for
this is simple: Different organizations use different
applications, which in turn expose diverse services.
One way to think about these applications in the on-
premises platform is to divide them into two broad
                                                            FROM ON-PREMISES               PLATFORMS          TO
Packaged applications: This includes business               CLOUD PLATFORMS
software such as SAP, Oracle Applications, and
Microsoft Dynamics, along with a myriad of other
off-the-shelf products. While not all packaged
applications expose services to other applications,
more and more of them do.

Custom applications: Many organizations have a
large investment in custom software. As these
applications increasingly expose their functionality
through services, they become part of the on premises
application platform. When it’s described like this,
the on-premises application platform can seem quite
complex. The truth, though, is that this platform has
evolved over time. In the early days of computing,
the application platform consisted of nothing more
than an on-premises foundation. (Think of MVS and
IMS on an IBM mainframe, for example.) In the
                                                            Along with describing on-premises platforms, the
1980s and 1990s, as distributed computing spread,
                                                            general model just described can also be used to think
on-premises infrastructure services were added, with
                                                            about cloud platforms. And since on-premises and
remote storage, integration, and identity becoming
                                                            cloud platforms can be used together, it’s important
common. Today, with the advent of service-oriented
                                                            to understand how the two work in concert. Figure 3
applications, on-premises application services have
                                                            illustrates this new world.
become part of the platform. The next step in this
As the figure shows, a cloud application can be built     provide these functions differs from what we’re used
on a cloud foundation, just as an on-premises             to, as this section shows.
application is built on an on-premises foundation.
Both kinds of applications can access infrastructure      Operating System
and application services provided on-premises and in      From a platform point of view, an operating system
the cloud. Just as on-premises platforms support          provides a set of basic interfaces for applications to
today’s                                                   use. By far the most well-known example of an
applications, cloud platforms provide services for the    operating system in the cloud today is Amazon’s
applications we’re likely to build tomorrow               Elastic Compute Cloud (EC2). EC2 provides
                                                          customer-specific Linux instances running in virtual
EXAMINING CLOUD PLATFORMS                                 machines (VMs). From a technical perspective, it
Understanding cloud platforms means looking at            might be more accurate to think of EC2 as a platform
each of their parts: the cloud foundation, cloud          for VMs rather than operating systems. Still, a
infrastructure   services,   and   cloud    application   developer sees an operating system interface, and so
services. This section walks through these three          viewing it in this light makes more sense here. Each
areas, using some of today’s most visible cloud           development team is free to use whatever local
platform technologies as examples. It is useful to        support it likes in this VM—Amazon doesn’t care.
look at on-premises platforms and cloud platforms         The creators of one application might choose a Java
through the same lens, the two aren’t identical. When     EE app server and MySQL, for example, while
platform functions move into the cloud, they              another group might go with Ruby on Rails. EC2
sometimes change in significant ways. For example,        customers are even free to create many Linux
on-premises platforms are designed to support (at         instances, then distribute large workloads across them
most) enterprise-scale applications. Applications that    in parallel, such as for scientific applications. While
run in the cloud, by contrast, can potentially operate    the service EC2 provides is quite basic, it’s also very
at Internet scale, which requires handling many more      general, and so it can be used in many different ways.
simultaneous users than any enterprise application.
                                                          Local Support
While the same kinds of platform functions might be
                                                          In an on-premises platform (and in EC2), a developer
needed in both cases, achieving this high scalability
                                                          can mix and match parts of the foundation as she sees
can force a cloud platform to provide them in a quite
                                                          fit. Choosing to use the .NET Framework on
different way. In what follows, expect to
                                                          Windows     doesn’t    mandate   using a     particular
see some differences from the on-premises world.
                                                          database, for example. Similarly, an on-premises
                                                          application using the .NET Framework is free to
                                                          access the underlying Windows operating system, as
Like their on-premises cousins, cloud foundations
                                                          is an application built on a Java EE server. The local
provide the basic local functions an application
                                                          support    functions   in    today’s   leading   cloud
needs. These can include an underlying operating
                                                          foundations don’t work this way. Instead, a cloud
system and local support. Yet how cloud platforms
                                                          local support technology typically includes its own
storage, and it hides whatever the underlying              tools. The intent, Microsoft says, is to allow
operating system might be. A developer choosing to         portability of both applications and developer skills
build on a particular local support option must accept     between the company’s on-premises
the limitations it imposes. There are good reasons for     foundation and its cloud foundation.
these limitations, of course. One of the things that
makes cloud computing so
attractive is its potential for scalability, but to make   CLOUD INFRASTRUCTURE SERVICES
an application built on a cloud foundation handle          Whether they run on-premises or in the cloud, some
Internet-size loads requires limiting it in some ways.     applications       don’t   need   anything    beyond     a
By making the local support functions more                 foundation. Still, many can benefit from distributed
specialized, a cloud platform provider has more            storage, common identity, and other infrastructure
freedom to optimize the application environment.           services. We’re accustomed to having these services
Accordingly, each set of local support functions in        provided on-premises today, but analogous services
cloud foundations today focuses on supporting a            are also provided in the cloud.
                                                           As the Figure showed, cloud infrastructure services
particular kind of application. For example, Google’s
                                                           can be accessed by applications running on either an
AppEngine provides local support for running Python
                                                           on premises foundation or a cloud foundation.
Web applications. Along with a standard Python
                                                           Initially,   the    most    common    users   of   cloud
runtime, AppEngine also includes a hierarchical data
                                                           infrastructure services will be on-premises, because
store with its own query language.
                                                           there aren’t yet many applications built on a cloud
Another example of a cloud platform providing local
                                                           foundation. Over time, expect this to change, as more
support is, offered by
                                                           and more cloud-based applications also use cloud
Rather than targeting general Web applications,
                                                           infrastructure services.
however, is aimed at creating data-
oriented business applications. Toward this end, it
provides its own focused support for data storage.
And rather than adopt an existing programming
                                                           Applications commonly use some kind of local
language, this platform’s creators invented their own,
                                                           storage, which is why storage is part of both on-
a language called Apex. Microsoft also provides local
                                                           premises and cloud foundations. Remote storage is
support for applications in the cloud as part of its
                                                           also useful, however, as the popularity of this service
CRM Live offering. Based on the Dynamics CRM
                                                           in the onpremises world shows. Accordingly, it’s
platform mentioned earlier, this technology targets
                                                           reasonable to expect that providing a storage service
data-oriented   business   applications,   much     like
                                                           in the cloud will be attractive for many applications. And like both and AppEngine,
                                                           As with on-premises platforms, remote storage in the
it includes both run-time application support and a
                                                           cloud comes in different styles. For example,
data store. Microsoft has also talked about its plans to
                                                           Amazon’s Simple Storage Service (S3) provides
go further in this area, with a platform that will
                                                           basic unstructured remote storage. The model it
support standard .NET development languages and
exposes to developers is straightforward: objects,        than a relational database—there’s no need to define
which are just bunches of bytes, are stored in buckets.   a schema up front—and it’s also easier to make
Applications can create, read, and delete objects and     scalable. Amazon’s SimpleDB provides one more
buckets. Objects can’t be updated, however—they           example of the value of structured storage in the
can only be entirely replaced. This is another            cloud. The way SimpleDB organizes information is
example of how platform services must change to           similar to SSDS—it’s a hierarchy of domains, items,
support Internet-scale usage, something that Amazon       and values—and it also provides a non-SQL query
is clearly focused on. This simple but limited storage    language. Like SSDS, no up-front schema definition
service is much easier to make scalable than a more       is required, and so the approach provides a mix of
fully featured offering would be. The trade-off is        flexibility and scalability.
clear: Application developers get cheap storage in the
cloud, but they might need to do more work in their       Integration
applications to use it effectively. Another approach to   Is there any application left that doesn’t talk to at
cloud storage is to support more structured data. In      least one of its fellows? Connecting applications has
Microsoft’s SQL Server Data Services (SSDS), for          become a staple of computing, and vendors have
example, a container includes one or more entities,       provided a plethora of on-premises infrastructure
each of which holds some number of properties, as         services to do it. These range from relatively simple
shown in Figure 4. An application can issue queries       technologies like message queues to quite complex
against a container’s data with operators such as ==,     integration servers.
!=, <, >, AND, OR, and NOT.                               As integration services move into the cloud, a range
                                                          of technologies is also appearing. For example,
                                                          Amazon’s Simple Queue Service (SQS) provides just
                                                          what its name suggests: a straightforward way for
                                                          applications to exchange messages via queues in the
                                                          cloud. Yet SQS once again illustrates what happens
                                                          when a familiar on-premises service is recast as a
                                                          cloud service. Because SQS replicates messages
                                                          across multiple queues, an application reading from a
                                                          queue isn’t guaranteed to see all messages from all
                                                          queues on a particular read request. SQS also doesn’t
                                                          promise in-order, exactly-once delivery. These
                                                          simplifications let Amazon make SQS more scalable,

It’s important to note that this isn’t a relational       but they also mean that developers must use SQS
                                                          differently from an on-premises message queuing
database, and the query language isn’t SQL. Once
again, we’re seeing an illustration of how application
                                                          BizTalk Services provides another example of cloud-
platform technologies change when they’re moved
into the cloud. This simpler approach is easier to use    based integration. Rather than using message
queuing, BizTalk Services implements a relay service      applied in many different scenarios. In fact, one
in the cloud that lets applications communicate           indication of the importance of this kind of identity
through firewalls. Cloud-based integration, such as       service is the number of cloud identity services
connecting applications in different organizations,       available today. Accessing Amazon cloud services
typically requires traversing firewalls, and so solving   such as EC2 or S3 requires presenting an Amazon-
this problem is important. BizTalk Services also          defined identity, for instance, while using Google
provides simple workflow support along with a way         AppEngine requires a Google account. Microsoft
for an application to register the services it exposes,   provides Windows Live ID, which can be used for
then let those services be invoked by any other           Microsoft applications and others, while BizTalk
application that has permission to do so. Going           Services also offers its own identity service, which
forward, expect to see more integration services          can be federated with others. Developers don’t have
offered in the cloud. Given the importance of             complete freedom—cloud platforms are frequently
integration as an on-premises service, it shouldn’t be    tied to a particular identity provider—but the need for
surprising to see its functions become part of the        identity as a cloud service is clear.
cloud infrastructure.
                                                          CLOUD APPLICATION SERVICES
                                                          What’s the difference between an application service
                                                          and an infrastructure service? To answer this
Whether an application runs on-premises or in the
                                                          question, think first about the obvious distinction
cloud, it typically needs to know something about its
                                                          between applications and infrastructure: Applications
users. Toward this end, the application commonly
                                                          are   designed     to    be    used    by   people,   while
demands that each user provides a digital identity, a
                                                          infrastructure is designed to be used by applications.
set of bytes that describes that user. Based on what
                                                          It’s also fair to say that infrastructure usually
these bytes contain and how they’re verified, the
                                                          provides a general, relatively low-level service, while
application can determine things such as who this
                                                          applications provide more specific, higher-level
user is and what they’re allowed to do.
                                                          services. An infrastructure service solves a broad
Many on-premises applications today rely on an on-
                                                          problem    faced        by    many    different   kinds   of
premises infrastructure service, such as Active
                                                          applications, while an application service solves a
Directory, to provide this identity information. When
                                                          more targeted problem. And just as it’s possible to
a user accesses a cloud application, however, or an
                                                          identify different kinds of infrastructure services, it’s
on-premises application accesses a cloud service, an
                                                          also possible to distinguish different categories of
on-premises identity usually won’t work. And what
                                                          application services, as this section illustrates.
about an application built on a cloud foundation?
Where does it get its identity information? An
identity service in the cloud can address these issues.
                                                          SaaS Application Services
Because it provides a digital identity that can be used
                                                          Users in most enterprises today rely on both
by people, by on-premises applications, and by cloud
                                                          purchased and home-grown applications. As these
applications, a cloud identity service can be
applications expose their services to remote software,          accurate to think of search as an application service
they become part of the on-premises platform.                   rather than an infrastructure service.
Similarly, SaaS applications today frequently expose
services that can be accessed by on-premises                    Mapping
applications      or      by   other   cloud    applications.   Many Web applications today display maps. Hotel’s CRM application, for example,                  Web sites plot their locations, retailers provide store
makes available a variety of services that can be used          locators, and more. The people who create these
to    integrate     its    functions    with    on-premises     applications probably don’t have the time, interest, or
applications. As organizations begin to create their            budget to create their own mapping database. Yet
own     SaaS      applications     running     on   a   cloud   enough applications need this function to justify
foundation, those applications will also expose                 creating a cloud application service that provides it.
services. Just as packaged and custom on-premises               This is exactly what’s done by mapping services such
applications today are part of the on-premises                  as Google Maps and Microsoft’s Virtual Earth. Both
platform, the services exposed by packaged and                  provide     cloud-based    services      that     application
custom SaaS applications are becoming part of the               developers can use to embed maps in Web pages and
cloud platform.                                                 more. And as with search, these mapping services are
                                                                adjuncts to existing Web sites that target users
Search                                                          directly, i.e., they’re cloud application services.
Services exposed by SaaS applications are useful, but
they’re not the whole story. Other kinds of cloud               CONCLUSION
application services are also important. Think, for
example, of search engines such as Google and Live              CONCLUSION
Search. Along with their obvious value to people,               A new kind of application platform doesn’t come
why can’t they also offer cloud application services?           along very often. But when a successful platform
The answer, of course, is that they can. Microsoft’s            innovation does appear, it has an enormous impact.
Live Search, for example, exposes services that allow           Think of the way personal computers and servers
on-premises and cloud applications to submit                    shook      up   the    world     of      mainframes      and
searches and get results back. Suppose a company                minicomputers, for example, or how the rise of
that provided a database of legal information wanted            platforms for Ntier applications changed the way
to let customers search both its own data and the Web           people write software. While the old world doesn’t
in a single request. They could accomplish this by              go away, a new approach can quickly become the
creating an on-premises application that both                   center of attention for new applications. Cloud
searched their proprietary data and, via the Live               platforms don’t yet offer the full spectrum of an on-
Search application service, the entire Web. It’s fair to        premises    environment.       For     example,     business
say that not many applications are likely to need this          intelligence as part of the platform isn’t common, nor
kind of service, but that’s one reason why it’s most            is   support    for   business       process    management
                                                                technologies such as full-featured workflow and rules
engines. This is all but certain to change, however, as
this technology wave continues to roll forward.
Cloud platforms aren’t yet at the center of most
people’s attention. The odds are good, though, that
this won’t be true five years from now. The
attractions of cloud-based computing, including
scalability and lower costs, are very real. If you work
in application development, whether for a software
vendor or an end user, expect the cloud to play an
increasing role in your future. The next generation of
application platforms is here.



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