QRA

QRA (Number Required for Operation) (運用に必要な数)

When there is one end-item at each site, you can portray simple (or k of n) redundancy for the end-item and its LRUs. The variable QRA (End Item/Config Data) represents the number of this item that may fail without the system failing. If you portray redundancy for the end-item, this is interpreted to mean that the number you entered as QPA for the end-item is the number located at an operating site and that a system failure does not occur unless more than QRA of the QPA end-items have failed.

If the QPA were 4, for example, then QRA may be 3, 2, or 1 in the order of greater redundancy. If QRA equals 4, there is no redundancy and QRA may not equal 0. QRA is equal to QPA by default. If a value of QRA is entered that exceeds the QPA and the number of end-items at a site exceeds 1, then QRA is ignored.

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