To take one example, an ObamaCare-mandated update to a major computer network called the System for Electronic Rate and Form Filing, which governs insurance approvals, has been delayed by months.

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The new systems include an online booking system, e-prescriptions and fast computer network links between NHS organisations as well as the electronic records system.

BBC: Electronic records is one part of the ?6.8bn IT upgrade

It may be useful to think of a computer network as being like a system of roads.

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After confirming the breach, the Chamber shut down and destroyed parts of its computer network, proceeding to revamp its security system over a 36-hour period.

ENGADGET: Chinese hackers target U.S. Chamber of Commerce, sensitive data stolen

Instead they are created by the system's network when a specific amount of computer work, known as a "block" has been completed.

BBC: Rewards set to halve for digital money miners

In January 2003 the Microsoft SQL Server worm, known as Slammer, infected a private computer network at David-Besse nuclear power plant in Oak Harbor, Ohio, disabling a safety monitoring system for nearly five hours, says the Nuclear Regulatory Commission.

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