Reference
Hot site
A “hot site” is a backup site equipped
with equivalent servers and functions of
the original site to enable rapid switchover in the event of a failure. Backup
data and updated information are transferred to the backup site. This is in contrast to a “cold site,” wherein a backup
system is installed and made operational in the event of a failure.
Reference
TCO
Abbreviation for “Total Cost of Ownership.”
Reference
Initial cost
“Initial cost” refers to the cost required
to install a system.
Initial costs include the purchase cost
for hardware and software, development labor costs (outsourcing costs),
training costs for users (system user
departments), and maintenance costs.
Reference
Operational cost
The “operational cost,” also called the
“running cost,” refers to the cost required to operate a system. Operational
costs include equipment maintenance
costs (such as leasing fees, rental fees,
upgrade costs, and labor costs for system administrators) and business losses from a shutdown of operations.
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(3)High reliability design
Concepts for constructing high reliability systems that users can be assured
of using at all times are summarized below.
Concept
Explanation
Fault tolerant
Maintains all of the normal functions even in the event of a failure,
allowing for processing to continue. Generally achieved by building a duplex system.
Fail soft
Maintains the minimum necessary functions in the event of a failure, preventing the system from coming to a complete halt.
Fail-safe
Secures the safe condition of a system in the event of a failure,
and limits the resulting impact. For example, if there is a failure
with a signal, the system acts to prevent the failure or malfunction
from leading to an accident by turning all the signals red and stopping the vehicle.
Foolproof
Ensures against failure, even if the system is used in a way beyond the scope of the original specifications.
3
Cost efficiency of systems
When installing a system, corporations must consider aspects of cost efficiency such as evaluation and benefits.
The installation of a system entails a wide variety of costs including initial
costs and operational costs. In considering the cost efficiency of a system,
it is necessary to emphasize “TCO (Total Cost of Ownership),” which
covers all necessary costs from the time of the system’s purchase to its disposal.
TCO encompasses all costs including the purchase cost for computer hardware and software, training costs for users (system user departments), operational costs, system maintenance costs, and cost of losses due to system
issues. It is used in the decision-making process for systems installation.
In considering the cost efficiency of a system, it is important to take into
account the continuous return on investment based on the TCO calculated
throughout the software life cycle.