Related characteristics
maturity
fault tolerance
recoverability
availability
degradability
Degradability
Description
Attributes of software that bear on the effort needed to re-establish the essential functionality after a breakdown.
Indicators
1. backsliding time
Per pre-defined breakdown, the time needed to re-establish operation of the degraded product.
Source: QUINT
Scale: ratio
Validity: **
Protocol:
1. Determine the essential (i.e. to be recovered) functions of the software product;
2. Specify the types of breakdown, for which a degraded product is relevant;
3. Simulate each type of breakdown with the use of hardware or system software;
4. Per breakdown, measure the time between first discovery of the breakdown by a user of the software product, and the recovery of the software product at a degraded level. This is the backsliding time.
Note: When the backsliding time is required to be extremely short, a degraded software product (e.g. a previous version) can be kept stand by.