The computer history museum explains the history of computing. It was established in 1996 at Mountain view, California, USA. The computer history museum's specialty is that it has many virtual online exhibits that can be retrieved by all over the world. This museum presents the computer revolution, stories and artifacts of the information age and its effect on society. It explains the history of computing before the 20th century. It is largest and most significant collection of computing artifacts. In the collection of museum there are nearly 90,000 objects, 4,000 feet of cataloged documentation, photographs and films and several hundred gigabytes of software. The exhibition whose name was "Revolution: The First 2000 Years of Computing," showed in 20 galleries covers from the abacus to the Internet. This exhibition is now available on internet. This museum is dedicated to preserving the history. First its name was TCMHC (The Computer Museum History Center). In year 2000 it was changed into Computer History Museum (CHM). CEO of The Computer History Museum is media executive John Hollar which was appointed in July 2008.There are 19 different alcoves with one alcove explaining one aspect of computing.