Installed base (also install base, install
''ed'' user base or just user base) is a measure of the number of units of a product or service that are actually in use, as opposed to
market share
Market share is the percentage of the total revenue or sales in a market that a company's business makes up. For example, if there are 50,000 units sold per year in a given industry, a company whose sales were 5,000 of those units would have a ...
, which only reflects sales over a particular period. Although the install base number is often created using the number of units that have been sold within a particular period, it is not necessarily restricted to just systems, as it can also be products in general. For products which are in use on some machines for many years, the installed base count will be higher than sales over a given period. Some people see it as a more reliable indicator of a platform's usage rate.
Installed base is not the same as the total number of units sold at any given moment in time (cumulative sales numbers), since some of those units will typically be out of use because they have broken, gone missing, or been made obsolete or replaced by newer versions.
See also
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Usage share of operating systems
*
Comparison of operating systems
References
External links
Web browsers' indications of operating system usage from w3schools.com
Market structure
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