A computer museum is a museum for the study of historic computer hardware and software. The International Council of Museums defines a "museum" as a "permanent institution in the service of society and of its development, open to the public, which acquires, conserves, researches, communicates, and exhibits the tangible and intangible heritage of humanity and its environment, for the purposes of education, study, and enjoyment".

Some computer museums are a part of larger institutions. For example, the Science Museum in London and the Deutsches Museum in Munich. Others, such as the Computer History Museum in Mountain View, California, the MuseumsForum in Paderborn, and The National Museum of Computing at Bletchley Park, deal only with computing. Some deal mainly in the early history of computing. Others focus in the era that started with the first personal computers such as the Apple I, Altair 8800, Apple IIs, older Apple Macintoshes, Commodore Internationals, Amigas, IBM PCs and more rare computers such as the Osborne 1. Some deal more on research and conservation. Some museums are for computer education and entertainment.  There are also private collections.

The term 'museum' has grown in common usage to include online collections, in much the same way other activities have made the change ('Online shopping', 'Online Gallery' etc.). Online Museums range in type and quality from those that collate and preserve material to those that simply show photographs of hardware from other sources. They are different from traditional museums mainly in that the exhibits can not be touched or interacted with in the traditional sense.

Further reading
Bell, Gordon (2011). Out of a Closet: The Early Years of the Computer Museums. Microsoft Technical Report MSR-TR-2011-44.
Bruemmer, Bruce H. (1987). Resources for the History of Computing: A Guide to U.S. & Canadian Records. Charles Babbage Institute.
Cortada, James W. (1990). Archives of Data-Processing History: A Guide to Major U.S. Collections. Greenwood

Notes and references

Other websites

Online museums
Bitsavers – Extensive software and document archive.
Bull computer History
Columbia University Computing History
Early Office Museum – Bookkeeping, adding, calculating, tabulating machines.
ENIAC Museum, University of Pennsylvania
IBM Archives
Information Processing Society of Japan – IPSJ Computer Museum
old-computers.com – , it includes 935 computers, 84 consoles and 98 pongs.
Russian Virtual Computer Museum
The Apple Museum – ...more than 350 Apple products listed
The Computer Collector
Videocard virtual museum – Videocard personal collection

North American museums
iMusée  (Montreal, Quebec, Canada)
Intel Museum (Santa Clara, Ca.)
Microsoft Visitor Center (Redmond, Wash.) – ...vision, products, culture, and history of Microsoft.
Old Computer Museum (Mass.) – Private collection
Smithsonian Computer History Collection (Wash. D.C.)

European museums 
Retro Computer Museum (Leicestershire, England) – Regular open days and hands-on events.
ComputerMuseum–Muenchen (Muenchen, Germany) – With a division for Seymour Cray/CDC/Cray Research 
FWT UNESCO Computer Museum (Padova, Italy)
Heinz Nixdorf Museum  (Paderborn, Germany) – Claims to be the largest.
House for the History of IBM Data Processing  (Sindelfingen, Germany)
The Jim Austin Computer Collection (York, England) – A private collection that can be visited by appointment.
The technikum29 museum (nr. Frankfurt-am-Main, Germany) – A small museum of computer and communications technology that specializes in maintaining and demonstrating equipment in fully working order.
The UK National Archive for the History of Computing  (Manchester, England) – Concentrates on the preservation of historical documents related to computing, rather than on the computers themselves.
Universiteit van Amsterdam – Computer Museum (The Netherlands)

Lists of Computer museums
Heinz Nixdorf MuseumsForum's extensive links for the history of computers and technology 
The Computer Collector: listing of collections, museums, historical information

Museums
Computers