• Fault

• Fix

• Cause and Effect

• Chart and Trend

• Align

• Stampers stamp readers stamp writers monitors

• (local, physical, reified) Data Sources (a.k.a. 'flat files', 'text files')

• Program Sources

• Cache Files

• In-Memory Caches

To use cache:

• cache must be present
• cache must be newer than its dependency artefacts

The list of (cache, raw and program) artefacts arranged by their modification dates must be a proper (monotonic?) sublist of the list of their logical dependencies.

In other words, if task A (modified at A.t) depends on artefact B (modified at B.t), then that gives us the dependency list [ A, B, ]

In the dependency chart we enter nodes in the chronological order that is needed for correct computation with cached intermediate artefacts.

If function f depends on some input file a.json (which may have changed on disk since the last output of f was written to cache), then we enter the temporal constraint ( t 'a.json' ) < ( t 'f' ) (read: the modification time of the object identified as 'a.json' must be less than that of 'f') as L.add g, 'a.json', 'f'.

'trending', 'the trend' 'drifting', 'the drift' 'the course' 'the chart'

dependency list vs timeline chart vs trend ?chart vs drift

series boxed series indexed series

fault: a mismatch between the ordering relations between a reference entry and a comparison entry as displayed in the chart on the one hand and in the trend on the other hand.

• use URLs like file:///home/url.json, cache://foo