It is the index which displays the entire expense which bets on the introduction and maintenance management etc. of the computer system. The American investigation company, lectured. In addition, when it points to the thing of the entire cost itself, it is.

When enterprise it constructs & uses the information system, purchase expense of the hardware and the software (conservative charge license expense) and other than the direct cost such as system development expense, "the cost which hides" occurs. TCO this including the cost which hides, is something which sums up everything which is necessary to utilize the system, is the index which is used in order to control the wasteful expense at the time of decision making and use when system investment is done.

Hides the cost which, (future) upgrade cost, labor cost of system section and the system manager (is spent to the education and Help to the end user the support cost which it is included), labor cost of the end user (installation and setup etc. help while job and the post and support job amount), due to system down and performance decrease etc. loss and trouble shooting etc. with respect to the business are included.

The case where of system investment is thought, not only early introduction expense, it is important to consider all costs via the life cycle of the system which includes the cost which hides, is method of thinking TCO. As a solution of TCO reduction, there is many a thing where system and ASP etc. are lectured.