Cloud Computing | Part 3

Cloud Computing | Part 3

Key Characteristics of Cloud Computing

Agility improves with users’ ability to rapidly and inexpensively re-provision technological infrastructure resources. Cost is claimed to be greatly reduced and capital expenditure is converted to operational expenditure. This ostensibly 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 fewer IT skills are required for implementation (in-house).

Device and location independence now 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, users can connect from anywhere.

Multi-tenancy enables sharing of resources and costs across a large pool of users thus allowing for:

Centralization of infrastructure in locations 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 cloud computing suitable for business continuity and disaster recovery. Nonetheless, many major cloud computing services have suffered outages, and IT and business managers can at times 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 could improve due to centralization of data, increased security-focused resources, etc., but concerns can persist about loss of control over certain sensitive data, and the lack of security for stored kernels. Security is often as good as or better than under 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. Furthermore, the complexity of security is greatly increased when data is distributed over a wider area and / or number of devices.

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

Maintenance cloud computing applications are easier to maintain, since they don’t have to be installed on each user’s computer. They are easier to support and to improve since the changes reach the clients instantly.

Layers Of Cloud Computing

A cloud client consists of computer hardware and/or computer software that relies on cloud computing for application delivery, or that is specifically designed for delivery of cloud services and that, in either case, is essentially useless without it. For example:

Mobile (Linux based – Palm Pre-WebOS Linux Kernel, Android-Linux Kernel, iPhone-Darwin Kernel, Microsoft based – Windows Mobile)

Thin client (CherryPal, Wyse, Zonbu, gOS-based systems)

Thick client / Web browser (Internet Explorer, Mozilla Firefox, Google Chrome, WebKit)

Cloud Computing – Application

A cloud application leverages cloud computing 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 (BOINC, Skype)

Web applications (Webmail, Facebook, Twitter, YouTube, Yammer)

Security as a service (MessageLabs, Purewire, ScanSafe, Zscaler)

Software as a service (Google Apps, Salesforce,Nivio,, Zoho,

Software plus services (Microsoft Online Services)

Distributed Storage

Content distribution (BitTorrent, Amazon CloudFront)

Synchronization (Dropbox, Live Mesh, SpiderOak, ZumoDrive)

Cloud Computing Platforms

A cloud platform (PaaS) delivers a computing platform and/or solution stack as a service, generally consuming cloud infrastructure and supporting cloud applications. It facilitates deployment of applications without the cost and complexity of buying and managing the underlying hardware and software layers. For example:


Identity (OAuth, OpenID)

Payments (Amazon Flexible Payments Service, Google Checkout, PayPal)

Search (Alexa, Google Custom Search, Yahoo! BOSS)

Real-world (Amazon Mechanical Turk)

Solution stacks

Java (Google App Engine)

PHP (Rackspace Cloud Sites)

Python Django (Google App Engine)

Ruby on Rails (Engine Yard, Heroku)

ColdFusion (Adobe)

.NET (Azure Services Platform, Rackspace Cloud Sites)

Proprietary (, WorkXpress, Wolf Frameworks)

Structured Storage

Databases (Amazon SimpleDB, BigTable)

File storage (Centerra Blades,Amazon S3, Nirvanix, Rackspace Cloud Files)

Queues (Amazon SQS)



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