 The failures can occur because of
damage,
failure,
design,
procedural (improper use by humans),
engineering (how to use and deployment),
overload (traffic or system resources stressed beyond designed limits),
environment (support systems like power and HVAC),
(outages designed into the system for a purpose such as software upgrades and equipment growth),
other (none of the above but known), or
unknown.The failures can be the responsibility of
customer/service provider,
vendor/supplier,
utility,
government,
contractor,
end customer,
public individual,
act of nature,
other (none of the above but known), or
unknown.Outages caused by system failures can have a serious impact on the users of computer/network systems, in particular those industries that rely on a nearly 24-hour service