[cap-talk] [Off-topic] Document linking in Microsoft OLE

[James A. Donald]

Discussion of a Microsoft Word document linking to an
external Excel document as evidence that durable
capabilities are required:

Karp, Alan H:
 > > > I open Word which has a link to a spreadsheet,
 > > > which means it has a capability to the
 > > > spreadsheet.

James A. Donald:
 > > In my current copy of Microsoft, Office 2007, there
 > > seems to be no easy way to create such a link.

David Hopwood wrote:
 > It could be done in Word 6/Excel 4 (IIRC) and in Word
 > 2000/Excel 2000 (definitely), so I would be rather
 > surprised if the functionality had been removed. [...]
 > click Paste Special... in the Edit menu - click Paste
 > Link,

I do that.

I save and close the Word file containing the link.  I
then change the external Excel file whose contents are
referenced by the Word file.

Upon reopening the Word file, I find that the word file
*asks* me for *permission* to access the external file,
rather than assuming an automatic right to dynamically
access the Excel file.  If I deny that, the Excel data
in the Word file acts as an ordinary paste, as Excel
data contained *inside* a Word file, not as a dynamic
link.

So, no permanent dynamic link exists, no durable
capability is required to support the existing software
behavior, and indeed creation of a durable capability
would confuse the user no end, since he would probably
forget that the data was dynamic, that the files were
linked, and be surprised, and indeed horrified, by the
data inside the Word file mysteriously changing without
apparent human action.  New permission must be regranted
every time the Microsoft word file is opened, implying
that permission is lost every time it is closed.  The
operating system does not restrain Word from acting
without permission, but Word restrains itself.

The existing software, when acting correctly acts as
though based on strictly transient capabilities provided
through a powerbox, and indeed systems that would
require durable capabilities always require a project
file management user interface to display what would be
the durable capabilities and allow the user to provide
them, edit them and control them in a project file, or
else the user is apt to get hopelessly confused.

The capabilities provided by a project file are also
transient, in that they only operate when the project
file is open and can only be exercised through software
launched through the project file, but they are durable
in that the user may choose to reopen the project file.

Even though the operating sysem permits the software to
act as if it can receive durable capabilities through
the user interface, such action always mystifies the
user, so well written software never acts like that.

All we have to do is fix the operating system so that
not only does well written software never do such
things, badly written software is incapable of doing
such things.

A powerbox should be incapable of providing durable
capabilities, for such capabilities are too scary and
confusing for the user.