Bernd Oppolzer wrote:
The RENT attribute is not ignored for unauthorized programs. The program is
still treated as reentrant (no new LOAD; no wait for completion of other
processes), only the write protection is not set.
Of course, that's what I meant. The RENT option is ignored for
unauthorized code within the context of the conversation we were having.
Now consider the following:
We have modules that try to improve performance by doing complex computations
only once.
The modules are RENT, because they are used in a dialog environment.
This is usually implemented by having a static pointer which is initialized
with zero. The first time the module is called the static pointer is
inspected. If still zero, the computation has to be done and in the end
the static pointer is changed to the location of the result (usually a table
of results, depending on the various inputs).
We call this a "Gedaechtnis" (german for memory).
The worst thing that could happen if the module is called in parallel is
that the computation is done multiple times. If the module has completed the
computation, it checks again the pointer, and if now not zero, it throws away
its results, because another process has already completed the computation.
For a logic of this kind, I need RENT programs which can be changed.
"If you build it, they will come." ;-)
The behavior of any operating system service, whether judged good or
bad, will be exploited by someone, somewhere. And, if that behavior is
ever changed, someone will complain. If unauthorized RENT programs were
loaded into protected storage by the operating system, you would have
found another way of providing this Gedaechtnis. All you're really
pointing out is that it's too late now to change any existing CSV
behaviors re: RENT. No argument there. Nobody has suggested those
existing behaviors be changed.
However, this post serves to further underscore the validity of my
suggestion re: the REFR attribute. It is an old option that is not
currently being exploited by the operating system. It could be "added"
in an upward compatible way. (See Jim Mulder's post in this thread.) I'm
sure there are a few existing programs, erroneously marked REFR, that
deliberately modify themselves. Those programs will need to be relinked.
For everything else, it's business as usual. ...
--
Edward E Jaffe
Phoenix Software International, Inc
5200 W Century Blvd, Suite 800
Los Angeles, CA 90045
310-338-0400 x318
[EMAIL PROTECTED]
http://www.phoenixsoftware.com/
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