A retained-document archive. Each record fixes one document at one moment — the URL it
was retrieved from, the date, a SHA-256 of the file as retrieved, and where an
independent archive holds a copy. Records are written one at a time, when a document is
captured or when a link recorded for a source is found dead:
18 records across 18 sources.
Documents are linked, never rehosted. The hash is the integrity claim:
it lets anyone confirm that the file they hold is the file that was read on that date.
This is not the observation series. A record's address here —
/archive/<source>/<version>/ — names one retained
retrieval, not a day in a series, and the SHA-256 on it was computed from that
retrieval's own bytes rather than drawn from the series. This site separately retrieves
each tracked source on a repeating schedule and records one observation per fetch. Not
every fetch produces a digest: 12,646 of
18,012 recorded observations carry a
content_hash. That series is published in full at
/api/v1/observations.json, and
where a source has an instrument page and its most recent observation recorded a hash,
that hash appears on the page: 90 of the 150 sources in the series. No
hash appears on a page for the other 60 — 18 are observed under an
id this site publishes no instrument page for; of those that have one, 6 have
never recorded a hash and 36 recorded their most recent one at an earlier
observation.
5 original link(s) no longer resolve.
They are flagged below and the archive link is the remaining route to the document.
This source also holds
2 distinct retained
readings in the observation series, over a different referent from
the records below:
compare any two of them.
This source also holds
2 distinct retained
readings in the observation series, over a different referent from
the records below:
compare any two of them.
This source also holds
3 distinct retained
readings in the observation series, over a different referent from
the records below:
compare any two of them.
This source also holds
3 distinct retained
readings in the observation series, over a different referent from
the records below:
compare any two of them.
This source also holds
2 distinct retained
readings in the observation series, over a different referent from
the records below:
compare any two of them.
This source also holds
4 distinct retained
readings in the observation series, over a different referent from
the records below:
compare any two of them.
This source also holds
2 distinct retained
readings in the observation series, over a different referent from
the records below:
compare any two of them.
This source also holds
2 distinct retained
readings in the observation series, over a different referent from
the records below:
compare any two of them.
ich-q10 — removed from scope on .
removed from scope — a quality-management instrument, cited by tracked instruments but not itself governing computerised systems The snapshots below stay: a retained
snapshot outlives a scope decision, which is why it was retained.
This source also holds
8 distinct retained
readings in the observation series, over a different referent from
the records below:
compare any two of them.
This source also holds
9 distinct retained
readings in the observation series, over a different referent from
the records below:
compare any two of them.
Separately from the records above, this site retrieves each tracked source on
a repeating schedule and, where text can be extracted, retains the normalised
text it hashed. Where two of those readings differ, the difference between
them can be computed.
The two digests are of different things. A SHA-256 above is
over one retrieved file, byte for byte. A digest on a comparison timeline is
over the normalised text of one observation, with scripts, comments and page
chrome removed and tags stripped before hashing. Neither reproduces the
other, and a comparison drawn across them would be a comparison of a file
with a projection of a page.
Two or more distinct retained readings are held for
85 of the 132 tracked entries. Every
pair of them carries either the difference or the condition that
refused it, and the conditions are stated at
the comparison index.
Tracked rows holding two or more distinct retained readings