This is an excerpt from
Knowledge-Domain Interoperability and an Open Hyperdocument
System by Douglas Engelbart.
It makes a handy measuring stick for collaborative systems.
See a paper on the topic: An Evaluation of the World Wide Web as a
Platform for Electronic Commerce
of an Open Hyperdocument System
- Mixed Object Documents
- to provide for an arbitrary mix of text, diagrams, equasions,
tables, raster-scan images (single frames, or even live video), spread
sheets, recorded sound, etc. -- all bundled within a common "envelope"
to be stored, transmitted, read (played) and printed as a coherent
entity called a "document."
- Explicitly Structured Documents
- where the objects comprising a document are arranged in an
explicit hierarchical structure, and compund-object substructures may
be explicitly addressed for access or manipulation of the structural
- View Control of Object's Form, Sequence, and Content
- where a structured, mixed-object document may be displayed in a
window according to a flexible choice of viewing options -- especially
by selective level clipping (outline for viewing), but also by
filtering on content, by truncation or some algorithmic view that
provides a more useful view of structure and/or object content
(including new sequences or groupings of objects that actually reside
in other documents). Editing on structure or object content from such
special views would be allowed whenever appropriate.
- The Basic "Hyperdocument"
- where embedded objects called "links" can point to any arbitrary
object within the document, or within another document in a specified
domain of documents -- and the link can be actuated by a user or an
automatic process to "go see what is at the other end," or "bring the
other-end object to this location," or "execute the process identified
a the other end." (These executable processes may control peripheral
devices such as CD ROM, video-disk players, etc.)
- Hyperdocument "Back-Link" Capability
- when reading a hyperdocument online, a worker can utilize
information about links from other objects within this or other
hyperdocuments that point to this hyperdocument -- or to designated
objects or passages of interest in this hyperdocument.
- The Hyperdocument "Library System"
- where hyperdocuments can be submitted to a library-like service
that catalogs them and guarantees access when referenced by its
catalog number, or "jumped to" with an appropriate link. Links within
newly submitted hyperdocuments can cite any passages within any of the
prior documents, and the back-link service lets the online reader of a
document detect and "go examine" any passage of a subsequent document
that has a link citing that passage.
- Hyperdocument Mail
- where an integrated, general-purpose mail service enables a
hyperdocument of any size to be mailed. Any embedded links are also
faithfully trasmitted -- and any recipient can then follow those links
to their designated targets in other mail items, in common-access
files, or in "library" items.
- Personal Signature Encryption
- where a user can affix his personal signature to a document, or a
specified segment within the document, using the private signature
key. Users can verify that the signature is authentic and that no bit
of the signed document or document segment has been altered since it
- Access Control
- Hyperdocuments in personal, group, and library files can have
access restrictions down to the object level.
- Link Addresses That Are Readable and Interpretable by Humans
- one of the "viewing options" for displaying/printing a link
object should provide a human-readable description of the "address
path" leading to the cited object; AND, that the human must be able to
read the path description, interpret it, and follow it (find the
destination "by hand" so to speak).
- Every Object Addressable
- in principal, every object that someone might validly want/need
to cite should have an unambiguous address (capable of being protrayed
in a manner as to be human readable and interpretable). (E.g. not
acceptable to be unable to link to an object within a "frame" or
- Hard-Copy Print Options to Show Address of Objects and Address
Specification of Links
- so that, besides online workers being able to follow a
link-citation path (manually, or via an automatic link jump), people
working with associated hard copy can read and interpret the
link-citation, and follow the indicated path to the cited object in
the designated hard-copy document.
Also, suppose that a hard-copy worker wants to have a link to a
given object established in the online file. By visual inspection of
the hard copy, he should be able to determine a valid address path to
that object and for instance hand-write an appropriate link
specification for later online entry, or dicatate it over a phone to a
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