Exploring Platform as a Service

With Platform as a Service systems, you are given a toolkit to work with, a virtual machine to run your software on, and it is up to you to design the software and its user-facing interface in a way that is appropriate to your needs. So PaaS systems range from full-blown developer platforms like Windows Azure Platform to systems like Drupal, Squarespace, Wolf, and others where the tools are modules that are very well developed and require almost no coding.

Many Content Management Systems (CMS) are essentially PaaS services where you get standard parts and can build Web sites and other software like Tinker Toys.

The services provided by PAAS model is:

• Application development: A PaaS platform either provides the means to use programs you create in a supported language or offers a visual development environment that writes the code for you.
• Collaboration: Many PaaS systems are set up to allow multiple individuals to work on the same projects.
• Data management: Tools are provided for accessing and using data in a data store.
• Instrumentation, performance, and testing: Tools are available for measuring your applications
and optimizing their performance.
• Storage: Data can be stored in either the PaaS vendor's service or accessed from a third-party storage service.
• Transaction management: Many PaaS systems provide services such as transaction managers or brokerage service for maintaining transaction integrity.

PaaS systems exist to allow you to create software that can be hosted as SaaS systems or to allow for the modification of existing SaaS applications.

A good PaaS system has certain desirable characteristics that are important in developing robust, scalable, and hopefully portable applications. On this list would be the following attributes:
• Separate of data management from the user interface
• Reliance on cloud computing standards
• An integrated development environment (IDE)
• Lifecycle management tools
• Multi-tenant architecture support, security, and scalability
• Performance monitoring, testing, and optimization tools
 

Salesforce.com versus Force.com: SaaS versus PaaS

Force.com. Salesforce.com is a Web application suite that is an SaaS. Force.com is Salesforce.com's PaaS platform for building your own services.

The Salesforce.com team created hosted software based on a cloud computing model: pay as you go, simple to use, and multifunctional. The Salesforce.com platform looks like a typical Web site such as Amazon.com, with a multi-tabbed interface—each tab being an individual application.
 
Some of the applications included in the site are:
• Accounts and Contact
• Analytics and Forecasting
• Approvals and Workflow
• Chatter (Instant Messaging/Collaboration)
• Content Library
• E-mail and Productivity
• Jigsaw Business Data
• Marketing and Leads
• Opportunities and Quotes
• Partner Relationship
• Sales
• Service and Support

Because Salesforce.com is browser-based, it is platform-independent. However, the company has extended its audience to mobile devices, such as the Android, Blackberry, iPhone, and Windows Mobile Devices. It also has a server product that supports Salesforce.com applications in-house called the Resin Application Server.

The PAAS platform Force.com uses a Java-based programming language called Apex for its application building, and it has an interface builder called Visualforce that allows a developer to create interfaces using HTML, Flex, and AJAX. Visualforce uses an XML-type language in its visual interface builder.

Application development

A PaaS provides the tools needed to construct different types of applications that can work together in the same environment. These are among the common application types:
• Composite business applications
• Data portals
• Mashups of multiple data sources

A mashup is a Web page that displays data from two or more data sources. The various landmarks and overlays you find in Google Earth, or annotated maps, are examples of mashups.

These applications must be able to share data and run in a multi-tenant environment. To make applications work together more easily, a common development language such as Java or Python is usually offered. The more commonly used the language is, the more developers and developer services are going to be available to help users of platform applications. The use of application frameworks such as Ruby on Rails is useful in making application building easier and more powerful.

All PaaS application development must take into account lifecycle management. As an application ages, it must be upgraded, migrated, grown, and eventually phased out or ported. Many PaaS vendors offer systems that are integrated lifecycle development platforms. That is, the vendor provides a full software development stack for the programmer to use, and it isn't expected that the developer will need to go outside of the service to create his application.

An integrated lifecycle platform includes the following:
• The virtual machine and operating system (often offered by an IaaS)
• Data design and storage
• A development environment with defined Application Programming Interfaces
• Middleware
• Testing and optimization tools
• Additional tools and services

Google AppEngine, Microsoft Windows Azure Platform, Eccentex AppBase, LongJump, and Wolf are examples of integrated lifecycle platforms.

Some PaaS services allow developers to modify existing software. These services are referred to as anchored lifecycle platforms. Examples of an anchored lifecycle platform are QuickBooks.com and Salesforce.com. The applications in these two services are fixed, but developers can customize which applications the users see, how those applications are branded, and a number of features associated with the different applications. 

Using PaaS Application Frameworks

Application frameworks provide a means for creating SaaS hosted applications using a unified
development environment or an integrated development environment (IDE).

Many Web sites are based on the notion of information management and organization; they are referred to as content management systems (CMS). A database is a content management system, but the notion of a Web site as a CMS adds a number of special features to the
concept that includes rich user interaction, multiple data sources, and extensive customization and extensibility.

Some examples of Paas Application frameworks are:

• Drupal

The Drupal CMS is an example of this type of PaaS. It is extensively used and has broad industry impact, and it is a full-strength developer tool.

Note: The portability of the applications you create in a PaaS is an extremely valuable feature. If your service goes out of business, being able to port an application by simply redeploying that application to another IaaS can be a lifesaver. 

• Squarespace

Squarespace (http://www.squarespace.com/), is an example of a next-generation Web site builder and deployment tool that has elements of a PaaS development environment.

• Eccentex

Eccentex is a Culver City, California, company founded in 2005 that has a PaaS development platform for Web applications based on SOA component architecture to create what it calls Cloudware applications using its AppBase architecture.

• LongJump

LongJump (http://www.longjump.com/) is a Sunnyvale, California, company hosting service created in 2003 with a PaaS application development suite. Its development environment is based on Java and uses REST/SOAP APIs. LongJump's PaaS is based on standard Java/JavaScript, SOAP, and REST.

• WaveMaker

WaveMaker (http://www.wavemaker.com/) is a visual rapid application development environment for creating Java-based Web and cloud Ajax applications. The software is open-source and offered under the Apache license. WaveMaker is a WYSIWYG (What You See is What You Get) drag-and-drop environment that runs inside a browser. The metaphor used to build applications is described as the Model-View-Controller system of application architecture.

• Wolf Frameworks

Many application frameworks like Google AppEngine and the Windows Azure Platform are tied to the platform on which they run. You can't build an AppEngine application and port it to Windows Azure without completely rewriting the application. There isn't any particular necessity to build an application framework in this way, but it suits the purpose of these particular vendors: for Google to have a universe of Google applications that build on the Google infrastructure, and for Microsoft to provide another platform on which to extend .NET Framework applications for their developers.

If you are building an application on top of an IaaS vendor such as AWS, GoGrid, or RackSpace, what you really want are application development frameworks that are open, standards-based, and portable. Wolf Frameworks is an example of a PaaS vendor offering a platform on which you can build an SaaS solution that is open and cross-platform.

Wolf Frameworks is based on the three core Windows SOA standard technologies of cloud computing:
• AJAX, asynchronous Java
• XML
• .NET Framework

Wolf Frameworks uses a C# engine and supports both Microsoft SQL Server and MySQL database. Applications that you build in Wolf are 100-percent browser-based and support mashable and multisource overlaid content.