Earliest credible time

This page is generated from the code and must not be edited by hand.

Each file is given the earliest time it is known to have existed: a time written inside it, where one was read, and otherwise the earlier of its creation and its last change, since a copy is created after it was last changed; an impossible time, such as one from 1969 or one later than the scan that saw the file, is set aside; a document’s creation date that is really the date of the blank template it was made from (midnight, years before the document was saved) is kept but not believed; where the time came from is kept with it, and a stand-in file is left out.

earliest_credible_time version 3

• Kind of rule: What files are (classifies). Says what a file or a folder is, by placing it in a class.

• What it concludes: a class

• Reasoning: defeasible. A conclusion is usually right, and is retracted when a rule it names concludes against it.

• What it reads: one file at a time

Is it available in this version?

Yes. The engine runs it.

What would defeat it

What this rule concludes about something is withdrawn when any of these rules concludes about the same thing:

• placeholder_from_entry_kind: A shortcut, or a file that claims a size but takes up no room on the disk, is taken to stand in for contents kept somewhere else.

Parameters

Parameter	Shipped value	May be	What it does
earliest_credible_year	1990	whole number, from 1970 to 2100	No time before this year is credible. Set it lower for older data.
future_tolerance_seconds	86400	whole number, from 0 to 31536000	How far past the run that observed a file one of its times may lie, for a clock’s skew between machines.
template_stamp_observers	["office", "spreadsheet"]	list of text	The readers of an Office package’s own properties whose creation stamp may be judged a blank template’s; a PDF’s dates are never judged. An empty list judges none.
template_stamp_minimum_gap_days	365	whole number, from 1 to 36500	How long before a document’s own last save a creation stamp at midnight UTC must lie to be judged the template’s it was made from. Microsoft’s blank workbook and presentation are stamped 2006, seventeen years and more before documents saved from them now; a year keeps a document really begun at midnight and saved within the year.