SOFTWARE
ARCHITECTURE Artisanal summaries
Version: 2.0
22-02-2025
Book Summary
,Software design vs software architecture
Verification: verifies the integrity of the architecture from a system’s (technical) perspective.
You could say, checking the grammar of the architecture.
Validation: validating not only if the architecture is correct but if it is the correct architecture for
the intended purpose. This can only be validated with the outside world.
2
, Availability
Reliability: the ability of software to be ready to carry out a task when needed without failures.
Recovery: the process the process of restoring information systems to a known state after a
disruption, compromise, or failure. [1]
Faults
Another part of availability is the ability of a system to mask or
repair faults in order to prevent them from being a failure.
Fault: a defect or deviation in a system that can disrupt its intended
operation.
Failure: a deviation of the system from its specification that is
externally visible.
Error: intermediate state between the occurrence of a fault and the
occurrence of a failure.
Degraded operating mode: the amount of functionality that remains operational within the
system in case of failure.
Availability tactics
Detect faults
• Monitor, analyze the system of a longer period
of time to detect deviations from its normal
operating behavior. Monitors can either initiate
self-tests or be the component to detect faulty
timestamps or missed heartbeats.
• Ping/Echo, check if a component is active by checking if it
responds. This ping is usually sent by a system monitor.
Pings await a response until a specified time threshold after
which they will fail (time out).
• Heartbeat, the health of the system is periodically checked
using a message exchange that is initiated by the
component itself which is called the node. The receiver of
the heartbeat is referred to as monitor. [2]
3
ARCHITECTURE Artisanal summaries
Version: 2.0
22-02-2025
Book Summary
,Software design vs software architecture
Verification: verifies the integrity of the architecture from a system’s (technical) perspective.
You could say, checking the grammar of the architecture.
Validation: validating not only if the architecture is correct but if it is the correct architecture for
the intended purpose. This can only be validated with the outside world.
2
, Availability
Reliability: the ability of software to be ready to carry out a task when needed without failures.
Recovery: the process the process of restoring information systems to a known state after a
disruption, compromise, or failure. [1]
Faults
Another part of availability is the ability of a system to mask or
repair faults in order to prevent them from being a failure.
Fault: a defect or deviation in a system that can disrupt its intended
operation.
Failure: a deviation of the system from its specification that is
externally visible.
Error: intermediate state between the occurrence of a fault and the
occurrence of a failure.
Degraded operating mode: the amount of functionality that remains operational within the
system in case of failure.
Availability tactics
Detect faults
• Monitor, analyze the system of a longer period
of time to detect deviations from its normal
operating behavior. Monitors can either initiate
self-tests or be the component to detect faulty
timestamps or missed heartbeats.
• Ping/Echo, check if a component is active by checking if it
responds. This ping is usually sent by a system monitor.
Pings await a response until a specified time threshold after
which they will fail (time out).
• Heartbeat, the health of the system is periodically checked
using a message exchange that is initiated by the
component itself which is called the node. The receiver of
the heartbeat is referred to as monitor. [2]
3
