Re: Dienst and BFD/LIFN document

Rick Troth (
Tue, 16 Aug 1994 21:36:04 +0200

Something Reed said made me start thinking (again) about
metadata/metainfo, information about an object (document) that
might not be, or might not should be, or might not be able to be
embedded in the file itself. Things like timestamps, size, etc.
Even ownership and sometimes authorship.

It was expiration and cycle time. Yeah ... that was it.
Two of the meta-values, which are kinda distinct, are an expiration
date and a cycle time or cache time-out. Once an expiration date
is reached, you can the object. But a cycle time is different:
you try to get a new copy. If it doesn't exist, then you can your
local copy. Otherwise you simply refresh it. A proxy server will
typically have just a global cycle time, unless it's smart enough
to acquire and understand a per-object cycle time.

These are the kinds of values that we can put into HTML,
but not into other markups/languages, plain text, PostScript, etc.

Rick Troth <>, Rice University, Information Systems