INTRODUCTION

Computing in its purest form, has changed hands multiple times. First, from near the beginning mainframes were predicted to be the future of computing. Indeed mainframes and large scale machines were built and used, and in some circumstances are used similarly today. The trend, however, turned from bigger and more expensive, to smaller and more affordable commodity PCs and servers.

Most of our data is stored on local networks with servers that may be clustered and sharing storage. This approach has had time to be developed into stable architecture, and provide decent redundancy when deployed right. A newer emerging technology, cloud computing, has shown up demanding attention and quickly is changing the direction of the technology landscape. Whether it is Google’s unique and scalable Google File System, or Amazon’s robust Amazon S3 cloud storage model, it is clear that cloud computing has arrived with much to be gleaned from.

Cloud computing is a style of computing in which dynamically scalable and often virtualizes 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.

Need for large data processing

We live in the data age. It’s not easy to measure the total volume of data stored electronically, but an IDC estimate put the size of the “digital universe” at 0.18 zettabytes in 2006, and is forecasting a tenfold growth by 2011 to 1.8 zettabytes.
Some of the large data processing needed areas include:-

• The New York Stock Exchange generates about one terabyte of new trade data per day.

• Facebook hosts approximately 10 billion photos, taking up one petabyte of storage.

• Ancestry.com, the genealogy site, stores around 2.5 petabytes of data.

• The Internet Archive stores around 2 petabytes of data, and is growing at a rate of 20 terabytes per month.

• The Large Hadron Collider near Geneva, Switzerland, will produce about 15 petabytes of data per year.

The problem is that while the storage capacities of hard drives have increased massively over the years, access speeds—the rate at which data can be read from drives have not kept up. One typical drive from 1990 could store 1370 MB of data and had a transfer speed of 4.4 MB/s,§ so we could read all the data from a full drive in around five minutes. Almost 20 years later one terabyte drives are the norm, but the transfer speed is around 100 MB/s, so it takes more than two and a half hours to read all the data off the disk. This is a long time to read all data on a single drive—and writing is even slower. The obvious way to reduce the time is to read from multiple disks at once. Imagine if we had 100 drives, each holding one hundredth of the data. Working in parallel, we could read the data in under two minutes.This shows the significance of distributed computing.

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ABSTRACT

Yii is a high-performance component-based PHP framework for developing large-scale Web applications. It enables maximum reusability in Web programming and can significantly accelerate the development process. The name Yii (pronounced as Yee or [ji:]) stands for easy, efficient and extensible.

What is Yii Best for?

Yii is a generic Web programming framework that can be used for developing virtually all sorts of Web applications. Because it is light-weighted and equipped with sophisticated caching solutions, it is especially suitable for developing high-traffic applications, such as portals, forums, content management systems (CMS), e-commerce systems, etc.

How is Yii Compared with Other Frameworks?

Like most PHP frameworks, Yii is an MVC framework. Yii excels over other PHP frameworks in that it is efficient, feature-rich and clearly- documented. Yii is carefully designed from the beginning to fit for serious Web application development. It is neither a byproduct of some pro ject nor a conglomerate of third-party work. It is the result of the authors’ rich experience of Web application development and the investigation and reflection of the most popular Web programming frameworks and applications.

INTRODUCTION

The Yii framework is free software. It is released under the terms of the following BSD License.
1.1 New Features

This page summarizes the main new features introduced in each Yii release.

• Version 1.0.7

• Added support for displaying call stack information in trace messages

– Logging Context Information

• Added index option to AR relations so that related ob jects can be indexed using the values of a specific column

– Relational Query Options

• Version 1.0.6

• Added support for using named scope with update and delete methods:

– Named Scopes

• Added support for using named scope in the with option of relational rules

• Added support for profiling SQL executions

– Profiling SQL Executions

• Added support for logging additional context information

– Logging Context Information

• Added support for customizing a single URL rule by setting its urlFormat and case Sensitive options:

– User-friendly URLs

• Added support for using a controller action to display application errors:

– Handling Errors Using an Action

• Version 1.0.5

• Enhanced active record by supporting named scopes. See:

– Named Scopes

– Default Named Scope

– Relational Query with Named Scopes

• Enhanced active record by supporting lazy loading with dynamic query options. See:

– Dynamic Relational Query Options

• Enhanced CUrlManager to support parameterizing the route part in URL rules. See:

– Parameterizing Routes in URL Rules

1.2 What is Yii

Yii is a high-performance component-based PHP framework for developing large-scale Webapplications. It enables maximum reusability in Web programming and can significantly

accelerate the development process. The name Yii (pronounced as Yee or [ji:]) standsfor easy, efficient and extensible.

Requirements

To run an Yii-powered Web application, you need a Web server supporting PHP 5.1.0 or higher.

For developers who want to use Yii, understanding ob ject-oriented programming (OOP)is very helpful, because Yii is a pure OOP framework.

1.3 What is Yii Best for?

Yii is a generic Web programming framework that can be used for developing virtually all sorts of Web applications. Because it is light-weighted and equipped with sophisticated

caching solutions, it is especially suitable for developing high-traffic applications, such as

portals, forums, content management systems (CMS), e-commerce systems, etc.

1.4 How is Yii Compared with Other Frameworks?

Like most PHP frameworks, Yii is an MVC framework. Yii excels over other PHP frameworks in that it is efficient, feature-rich and clearly-documented. Yii is carefully designed from the beginning to fit for serious Web application development. It is neither a byproduct of some pro ject nor a conglomerate of third-partywork. It is the result of the authors’ rich experience of Web application development and the investigation and reflection of the most popular Web programming frameworks and applications.

1.4 Installation

Installation of Yii mainly involves the following two steps:

• Download Yii Framework from yiiframework.com.
• Unpack the Yii release file to a Web-accessible directory.

Requirements

After installing Yii, you may want to verify that your server satisfies all the requirementsof using Yii. You can do so by accessing the requirement checker script at the followingURL in a Web browser:

http://hostname/path/to/yii/requirements/index.php

The minimum requirement by Yii is that your Web server supports PHP 5.1.0 or above.

Yii has been tested with Apache HTTP server on Windows and Linux operating systems.

It may also run on other Web servers and platforms provided PHP 5 is supported.
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Download Full Article Cocoa.doc

ABSTRACT

Cocoa is one of Apple Inc.’s native object-oriented application program environments for the Mac OS X operating system. It is one of five major APIs available for Mac OS X; the others are Carbon, POSIX (for the BSD environment), X11 and Java.

Cocoa applications are typically developed using the development tools provided by Apple, specifically Xcode (formerly Project Builder) and Interface Builder, using the Objective-C language. However, the Cocoa-programming environment can be accessed using other tools, such as Object Pascal, Python, Perl and Ruby, with the aid of bridging mechanisms such as PasCocoa, PyObjC, CamelBones and RubyCocoa, respectively. Also, under development by Apple, is an implementation of the Ruby language, called MacRuby, which does away with the requirement for a bridging mechanism. It is also possible to write Objective-C Cocoa programs in a simple text editor and build it manually with GCC or GNUstep’s makefile scripts. For end-users, Cocoa applications are considered to be those written using the Cocoa-programming environment. Such applications usually have a distinctive feel, since the Cocoa-programming environment automates many aspects of an application to comply with Apple’s human interface guidelines.

Main frameworks

Cocoa consists primarily of two Objective-C object libraries called frameworks. Frameworks are functionally similar to shared libraries, a compiled object that can be dynamically loaded into a program’s address space at runtime, but frameworks add associated resources, header files, and documentation.

Foundation Kit, or more commonly simply Foundation, first appeared in OpenStep. On Mac OS X, it is based on Core Foundation. Foundation is a generic object-oriented library providing string and value manipulation, containers and iteration, distributed computing, run loops, and other functions that are not directly tied to the graphical user interface. The “NS” prefix, used for all classes and constants in the framework, comes from Cocoa’s NeXTSTEP heritage.

Application Kit or AppKit is directly descended from the original NeXTSTEP Application Kit. It contains code with which programs can create and interact with graphical user interfaces. AppKit is built on top of Foundation, and uses the same “NS” prefix. A key part of the Cocoa architecture is its comprehensive views model. This is organized along conventional lines for an application framework, but is based on the PDF drawing model provided by Quartz. This allows creation of custom drawing content using PostScript-like drawing commands, which also allows automatic printer support and so forth. Since the Cocoa framework manages all the clipping, scrolling, scaling and other chores of drawing graphics, the programmer is freed from implementing basic infrastructure and can concentrate only on the unique aspects of an application’s content.

Technology Overview

Cocoa helps you create commercial-grade applications quickly and efficiently. It is an advanced, mature object- oriented development environment that enables you to create complex software with surprisingly few lines of code. Through a seamless integration of tools and Cocoa API, the design and construction of a user interface is largely a matter of dragging windows, buttons, and other objects from palettes, initializing their attributes, and connecting them to other objects. Cocoa also defines a model for applications and implements most aspects of application behavior; you simply fit into this model the code that makes your application unique.

The programmatic interfaces of the core Cocoa frameworks, Foundation and Application Kit, simplify access to most of the technologies on which Mac OS X is based, such as Quartz, Bonjour networking, Core Text, and the printing system. Although these interfaces are in Objective-C, you can integrate code written in other languages into your Cocoa projects, including C++ code and C code. Because Objective-C is a superset of ANSI C, frameworks with C APIs are compatible with Objective-C.

Implementations

The Cocoa frameworks are written in Objective-C, and hence Objective-C is the preferred language for development of Cocoa applications. Java bindings for the Cocoa frameworks (known as the “Java bridge”) are also available but have not proven popular amongst Cocoa developers. Further, the need for runtime binding means many of Cocoa’s key features are not available with Java. In 2005, Apple announced that the Java bridge was to be deprecated, meaning that features added to Cocoa in Mac OS X versions later than 10.4 would not be added to the Cocoa-Java programming interface. AppleScript Studio, part of Apple’s Xcode Tools makes it possible to write (less complex) Cocoa applications using AppleScript. Third party bindings available for other languages include PyObjC (Python), RubyCocoa (Ruby), CamelBones (Perl), Cocoa#, Monobjc (C#) and NObjective(C#).There are also open source implementations of major parts of the Cocoa framework that allows cross- platform (including Microsoft Windows) Cocoa application development, such as GNUstep, and Cocotron

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