From: jst50986@uxa.cso.uiuc.edu (Jack S. Tan)
Subject: Re: programs and program objects
Organization: University of Illinois at Urbana
Date: Fri, 6 Nov 1992 22:46:08 GMT

djbpitt+@pitt.edu (David J Birnbaum) writes:

> According to The Unofficial Guide to the Workplace Shell (an excellent
> introduction by Jeff Cohen): "A program object is not the program
> itself, but a reference to it." He goes on to add: "Shredding a program
> object will not delete the program. You can also have as many program
> objects for a single program as you like ..."
>
> I just installed TE/2 and it created, among other things, a program
> object called "te2.exe". Selecting this object launches the program.
> Question:
>
> How do I delete the exe file named "te2.exe" from the WPS? If shredding
> the program object doesn't delete the program, and there is no data
> object that represents the actual file, how does the user get to the
> latter?It isn't that I want to delete TE/2 (I don't), but I'd like to
> understand the relationship between objects and physical files better.
> I had thought that every physical file, including exe programs, would
> have a corresponding data object that the user could manipulate for
> file system housecleaning. In addition, I though that an exe file could
> be pointed to by any number of program objects. My TE/2 directory seems
> to have one program object, but no accessible data object corresponding
> to the physical te2.exe file that I find on my disk.
>
> Thanks for any clarification.
>
> --David

Each file on the disk (any disk) is represented in the WPS as an object
which can be maniplulated in the WPS (e.g., dragged to the shredder or
printer or another folder).  Opening the Drive icon for a specific drive
will access these objects.  Taking an object from a drive and deleting it
*will* delete the actual file (this is not recommended, as objects destroyed
in the WPS cannot be UNDELETEd).

In many cases, you may wish to create an object in the WPS which runs a
program (this would be the program object).  Why would you want to create
such an object?  For one, it is easier to access an icon on the desktop or
one in your "DOS Applications" folder than hunting through the drive.  Also,
when you move the file around the drive (say, when doing periodic house-
cleaning), you don't need to remember the new location; the object you
created is all you need to access.  (This is a cool thing about the WPS -
program objects which point to files are automatically updated when files
are moved and shuffled.)  To create this program object, you would 'tear off'
a sheet from the Program Object template and fill in the the appropriate
blanks.  It is such an object that has no physical representation on the
drive (as a file) and can be deleted without harming the original.

With a template, the newly-created program object has attributes independent
of the original; it only points to the first.  This means that you can play
with the settings of the object without affecting the original.  If you need
an exact copy, then you would create a shadow of the original object (on the
pop-up menu).  The settings of a shadow are exactly the same as the original.
Any changes affecting the shadow also affect the original, and vice versa.
The only change that isn't propagated is deletion of a shadow:  deleting a
shadow does not delete the original (but the converse is not true).

Hope this helps.

-- 

Jack Tan                                     Sattinger's Law:
jahk@uiuc.edu                       It works better if you plug it in.