Google
...Brin and Larry Page met in 1995 as Stanford University graduate students. They created a search engine that combined the technologies of Page's PageRank system, which evaluates a page's importance based on the external links to it, and Erin's Web crawler, which visits Web sites and records a summary of their content. Because Google was so effective, it quickly became the search engine of choice for Web users. Today, Google handles nearly 50 percent of Web searches.
Google stopped displaying the number of Web pages it indexed after the number surpassed 8 billion in 2005, but some estimates now place the number at 25 billion. Google's index also includes one billion images and one billion Usenet newsgroup messages. In addition to searching for Web pages, Google users can search for PDF, PostScript, text, Microsoft Office, Lotus, PowerPoint, and Shockwave files. Google claims to be one of the five most popular sites on the Internet with more than 380 million unique users per month and more than 50 percent of its traffic coming from outside the United States.
Google's IT infrastructure is a closely guarded secret because it is part of its competitive advantage. The best guess is that Google has up to 450,000 servers spread over at least 25 locations around the world. These servers use inexpensive off-the-shelf hardware to run a customized version of the Linux operating system and other critical pieces of custom software. These include MapReduce, a programming model to simplify processing and create large data sets; Google WorkQueue, a system that groups queries and schedules them for distributed processing; and the Google File System, which keeps copies of data in several places so that the data will always be available even if a server fails.
According to a widely cited estimate, Google only needs to spend $1 for every $3 its competitors spend to deliver a...
View Full Essay
