Re: Formatless files

And sometimes what is a "program" and what is a file is not well defined.

Data can be programs, and programs can be data -- depending on who is the
observer:


   - Passing a function as a parameter to another function. In this case
   the parameter is kind of "data' for the 2nd function.
   - Loading an XPath function library from a file. This is "data" for the
   loader, but "code/program" for the importer.
   - The swap file is data for an OS that supports virtual memory, but is
   maybe "all the program" for the program, without it actually being aware of
   this.


Thanks,
Dimitre

On Sun, Aug 14, 2022 at 3:02 PM Michael Kay <[email protected]> wrote:

> >
> > There are many cases when we don't want "any program" to read our file.
> And by "read" I mean "understand / get / extract the useful information".
> >
> > Consider a file that contains the hashes of (salted) network-ids and/or
> passwords of the users in an organization, or a smaller subset of this
> organization.
> >
>
> A classic example was an online game we played as students called "moo" -
> think Wordle, but 50 years earlier - that maintained a shared file
> containing the league table of everyone's scores. The program needs read
> and write access to the file, but the user playing the game must be
> prohibited from accessing the file directly. Today's commodity operating
> systems don't make this easy: it typically requires multiple processes.
>
> Michael Kay
> Saxonica
>
>