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From: jones@pyrite.cs.uiowa.edu (Douglas W. Jones,201H MLH,3193350740,3193382879)
Newsgroups: comp.compression
Subject: Re: Question about patents and copyrights on algorithms...
Message-ID: <5478@ns-mx.uiowa.edu>
Date: 14 Apr 91 16:56:56 GMT
References: <1991Apr14.150509.1755@watserv1.waterloo.edu>
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From article <1991Apr14.150509.1755@watserv1.waterloo.edu>,
by dewinter@watserv1.uwaterloo.ca (Jack a.k.a. Wildside):
> 
> If a algorithm is patented or copyrighted, how much of the algorithm are
> programmers able to use?

A copyright covers the expression of an idea.  Neat tricks contained in a
copyrighted work may be used by others with no penalty, as long as they
don't express the same idea.  Think literature to understand this.  Just
because some plot has been used in a copyrighted work doesn't mean that
you can't borrow that plot, so long as you don't use the same turns of
phrase in expressing the plot.  If you think you can do a better job than
Michner in using the plot of one of his books, you're free to try.

Patents cover the idea itself, not the expression.  In classic (non
-software) patent law, there are two kinds of patents, process patents
and mechanism patents (I'll ignore design patents because they are really
a different kind of animal entirely).

In the former class, consider a chemical process for making paint thinner.
Such a process is described in terms of the initial chemical reagents, the
order in which they are combined, and the conditions of each processing
step.  For example, each step might be described in terms of a range of
temperatures, pressures, and durations, perhaps with specified catalyists
of types of containers.

Process patents apply to any process that fits the conditions specified,
no matter what mechanisms are used to carry out the process.  Thus,
substitution of a piston pump for a turbine pump, or substitution of
continuous flow methods for batch methods will make no difference, as long
as the same processing steps are carried out in the same order under the
same conditions.

Mechanism patents cover mechanisms, no matter what purpose the mechanism
serves.  For example, someone might once have patented the planetary
differential for use at the rear end of a car, and the patent on this
combination of gears would apply equally well if the same mechanism were
used in a differential analyzer.  The key is that the mechanism itself is
can be patented, irrespective of its use.

Now try to fit software into this mess!

Disclaimer -- I'm not a lawyer, so don't believe all I've said.

					Doug Jones
					jones@cs.uiowa.edu