z/VSE: 45 Years of Progress - z/VM - IBM

Cloud Computing Origins and Evolution
Where did the term “cloud” come from? Mature
mainframers remember the diagrams that people used
to show on their overhead projectors where links from
computers went into a cloud that represented the telephone
system and more links came out to terminals.
The “cloud part” came to represent the Internet on
numerous PowerPoint slides. Now, that cloud has
taken on a life of its own. In fact, if you search the
Internet, you’ll find that Feb. 24, 2007 is the day the
term “cloud computing” was coined.
Not all clouds are necessarily public clouds. A public
cloud would be one that sells services to anyone
on the Internet (like Amazon Web services). A private
cloud would be used by an organization to supply
hosted services to people within the organization.
There’s one slight complication to this simple dichotomy:
It’s possible for a private cloud to be made available
using public cloud resources. The result is
referred to as a virtual public cloud.
What is meant by a service? Services can be divided
into three categories:
• Infrastructure-as-a-Service (IaaS)
• Platform-as-a-Service (PaaS)
• Software-as-a-Service (SaaS).
These services can be distinguished from traditional
hosting because they’re sold on demand; users purchase
as much of a service as they want, when they
want it. Also, the service is managed by the provider.
The SaaS model involves deploying the software
over the Internet. The vendor provides the software,
any databases, and the servers it uses. The user
accesses the service, usually through a browser.
Available services range from invoicing to email to
database processing. The user (subscriber) simply
pays for what they use. The user could get a similar
service from a different provider if they were to
choose to do so.
The IaaS model occurs when an organization outsources
the equipment it needs for its IT infrastructure,
including storage, servers, and networking components.
A service provider owns all the hardware and
must maintain it. Users are given an IP address and
access to the supplier’s API to use their virtual hardware.
The advantage of this kind of computing is that
organizations pay only for the computing power they
use; it also allows them to get more as necessary.
The PaaS model facilitates deployment of applications
without a need to purchase and manage the
underlying hardware and software. Developers may use
APIs or software installed on their computer by the
vendor to develop Web applications and services. (A
Web application is basically an application accessed
over the Internet, or, possibly, an intranet. Web applications
are convenient and available through a Web
browser client. There’s no need for an organization to
continually update its software because the Web
application used is always the latest version. The
responsibility for updating and testing the Web application
lies with the provider.
Gartner Research is a big fan of cloud computing,
telling us that: “The use of cloud computing in general
has been spreading rapidly over the past few years,
as companies look for ways to increase operating efficiency
and data security. The cloud industry, which is
in its infancy, will generate $3.4 billion in sales this
year.” Similarly, Merrill Lynch predicts that by 2011
the cloud computing market will reach $160 billion,
including $95 billion in business and productivity
applications.
Most industry journals and conferences are focusing
on Microsoft’s Windows Azure, an environment for
development, service hosting, and service management
based on the cloud. It’s designed to allow developers
to compute, host, scale, store, and manage the
Web applications they create. Windows Azure relies on
the global network of Microsoft data centers to offer
the services; it lets developers use Microsoft Visual
Studio, along with SOAP, REST, XML, and PHP.
Finally, Google has a partnership with VMware to
develop a new operating system for the cloud. This
partnership is designed to enable users to avoid being
tied down to a single supplier by ensuring that applications
are portable. Companies will be able to build
and maintain their own applications to run in a
VMware environment on any infrastructure compatible
with Java standards. Google has said it will provide
cloud-based database and secure transaction services
this year.
— TE
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