Media & Data
Intermediate

Availability (Uptime)

Percentage of time a system is operational.

Formula

A=MTBFMTBF+MTTR×100A = \frac{MTBF}{MTBF + MTTR} \times 100

Variables

MTBFMean time between failures
MTTRMean time to repair

Example

MTBF 1000 h, MTTR 1 h → A = 99.9%

Did You Know?

"Five nines" (99.999%) availability allows only about 5 minutes of downtime a year.

data-centreitreliabilitysla

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Gross Rating Points (GRP)

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Total advertising weight of a campaign against the whole audience.

Target Rating Points (TRP)

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Advertising weight counted only within the specific target audience.

Television Rating (TVR)

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Share of all potential viewers watching a particular programme.

Cost Per Mille (CPM)

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The cost of reaching one thousand impressions.

Cost Per Rating Point (CPP)

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How much it costs to buy one rating point of audience.

Click-Through Rate (CTR)

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Percentage of ad views that result in a click.