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PART II - Against Software Patents
Software patents threaten to devastate America's computer
industry. Patents granted in the past decade are now being used
to attack companies such as the Lotus Development Corporation for
selling programs that they have independently developed. Soon
new companies will often be barred from the software arena - most
major programs will require licenses for dozens of patents, and
this will make them infeasible. This problem has only one
solution: software patents must be eliminated.
The patent system and computer programs
The framers of the United States Constitution established the
patent system so that inventors would have an incentive to share
their inventions with the general public. In exchange for
divulging an invention, the patent grants the inventor a 17 year
monopoly on its use. The patent holder can license others to use
the invention, but may also refuse to do so. Independent
reinvention of the same technique by others does not give them
the right to use it.
Patents do not cover specific systems: instead, they cover
particular techniques that can be used to build systems, or
particular features that systems can offer. Once a technique or
feature is patented, it may not be used in a system without the
permission of the patent-holder - even if it is implemented in a
different way. Since a computer program typically uses many
techniques and provides many features, it can infringe many
patents at once.
Until recently, patents were not used in the software field.
Software developers copyrighted individual programs or made them
trade secrets. Copyright was traditionally understood to cover
the implementation details of a particular program; it did not
cover the features of the program, or the general methods used.
And trade secrecy, by definition, could not prohibit any
development work by someone who did not know the secret.
On this basis, software development was extremely profitable,
and received considerable investment, without any prohibition on
independent software development. But this scheme of things is
no more. A change in U.S.: government policy in the early 1980's
stimulated a flood of applications. Now many have been approved,
and the rate is accelerating.
Many programmers are unaware of the change and do not appreciate
the magnitude of its effects. Today the lawsuits are just
The Patent Office and the courts have had a difficult time with
computer software. The Patent Office refused until recently to
hire Computer Science graduates as examiners, and in any case
does not offer competitive salaries for the field. Patent
examiners are often ill-prepared to evaluate software patent
applications to determine if they represent techniques that are
widely known or obvious - both of which are grounds for
Their task is made more difficult because many commonly-used
software techniques do not appear in the scientific literature of
computer science. Some seemed too obvious to publish while
others seemed insufficiently general; some were open secrets.
Computer scientists know many techniques that can be generalized
to widely varying circumstances. But the Patent Office seems to
believe that each separate use of a technique is a candidate for
a new patent. For example, Apple was sued because the Hypercard
program allegedly violates patent number 4,736,308, a patent that
covers displaying portions of two or more strings together on the
screen - effectively, scrolling with multiple subwindows.
Scrolling and subwindows are well-known techniques, but combining
them is now apparently illegal.
The granting of a patent by the Patent Office carries a
presumption in law that the patent is valid. Patents for well-
known techniques that were in use many years before the patent
application have been upheld by federal courts. It can be hard
to prove a technique was well known at the time in question.
For example, the technique of using exclusive-or to write a
cursor onto a screen is both well known and obvious. (Its
advantage is that another identical exclusive-or operation can be
used to erase the cursor without damaging the other data on the
screen.) This technique can be implemented in a few lines of a
program, and a clever high school student might well reinvent it.
But it is covered by patent number 4,197,590, which has been
upheld twice in court even though the technique was used at least
five years before the patent application. Cadtrak, the company
that owns this patent, collects millions of dollars from large
English patents covering customary graphics techniques,
including airbrushing, stenciling, and combination of two images
under control of a third one, were recently upheld in court,
despite the testimony of the pioneers of the field that they had
developed these techniques years before. (The corresponding
United States patents, including 4,633,416 and 4,602,286, have
not yet been tested in court, but they probably will be soon.)
All the major developers of spreadsheet programs have been
threatened on the basis of patent 4,398,249, covering "natural
order recalc" - the recalculation of all the spreadsheet entries
that are affected by the changes the user makes, rather than
recalculation in a fixed order. Currently Lotus alone is being
sued, but a victory for the plaintiff in this case would leave
the other developers little hope. The League has found prior art
that may defeat this patent, but this is not assured.
Nothing protects programmers from accidentally using a technique
that is patented, and then being sued for it. Taking an existing
program and making it run faster may also make it violate half a
dozen patents that have been granted, or are about to be granted.
Even if the Patent Office learns to understand software better,
the mistakes it is making now will follow us into the next
century, unless Congress or the Supreme Court intervenes to
declare these patents void.
However, this is not the whole of the problem. Computer
programming is fundamentally different from the other fields that
the patent system previously covered. Even if the patent system
were to operate "as intended" for software, it would still
obstruct the industry it is supposed to promote.
What is "Obvious"?
The patent system will not grant or uphold patents that are
judged to be obvious. However, the system interprets the word
"obvious" in a way that might surprise computer programmers. The
standard of obviousness developed in other fields is
inappropriate for software.
Patent examiners and judges are accustomed to considering even
small, incremental changes as deserving new patents. For
example, the famous "Polaroid vs. Kodak" case hinged on
differences in the number and order of layers of chemicals in a
film - differences between the technique Kodak was using and
those described by previous, expired patents. The court ruled
that these differences were unobvious.
Computer scientists solve problems quickly because the medium of
programming is tractable. They are trained to generalize
solution principles from one problem to another. One such
generalization is that a procedure can be repeated or subdivided.
Programmers consider this obvious - but the Patent Office did
not think that it was obvious when it granted the patent on
scrolling multiple strings, described above.
Cases such as this cannot be considered errors. The patent
system is functioning as it was designed to do - but with
software, it produces outrageous results.
Patenting what is too obvious to publish
Sometimes it is possible to patent a technique that is not new
precisely because it is obvious - so obvious that no one would
have published a paper about it.
For example, computer companies distributing the free X Window
System developed by MIT are now being threatened with lawsuits by
AT&T over patent number 4,555,775, covering the use of "backing
store" in a window system that lets multiple programs have
windows. Backing store means that the contents of a window that
is temporarily partly hidden are saved in off-screen memory, so
they can be restored quickly if the obscuring window disappears.
Early window systems were developed on computers that could not
run two programs at once. These computers had small memories, so
saving window contents was obviously a waste of scarce memory
space. Later, larger multiprocessing computers led to the use of
backing store, and to permitting each program to have its own
windows. The combination was inevitable.
The technique of backing store was used at MIT in the Lisp
Machine System before AT&T applied for a patent. (By
coincidence, the Lisp Machine also supported multiprocessing.)
The Lisp Machine developers published nothing about backing store
at the time, considering it too obvious. It was mentioned when a
programmers' manual explained how to turn it on and off.
But this manual was published one week after the AT&T patent
application - too late to count as prior art to defeat the
patent. So the AT&T patent may stand, and MIT may be forbidden
to continue using a method that MIT used before AT&T.
The result is that the dozens of companies and hundreds of
thousands of users who accepted the software from MIT on the
understanding that it was free are now faced with possible
lawsuits. (They are also being threatened with Cadtrak's
exclusive-or patent.) The X Window System project was intended
to develop a window system that all developers could use freely.
This public service goal seems to have been thwarted by patents.
Why software is different
Software systems are much easier to design than hardware systems
of the same number of components. For example, a program of
100,000 components might be 50,000 lines long and could be
written by two good programmers in a year. The equipment needed
for this costs less than $10,000; the only other cost would be
the programmers' own living expenses while doing the job. The
total investment would be less than a $100,000. If done
commercially in a large company, it might cost twice that. By
contrast, an automobile typically contains under 100,000
components; it requires a large team and costs tens of millions
of dollars to design.
And software is also much cheaper to manufacture: copies can be
made easily on an ordinary workstation costing under ten thousand
dollars. To produce a complex hardware system often requires a
factory costing tens of millions of dollars.
Why is this? A hardware system has to be designed using real
components. They have varying costs; they have limits of
operation; they may be sensitive to temperature, vibration or
humidity; they may generate noise; they drain power; they may
fail either momentarily or permanently. They must be physically
assembled in their proper places, and they must be accessible for
replacement in case they fail.
Moreover, each of the components in a hardware design is likely
to affect the behavior of many others. This greatly complicates
the task of determining what a hardware design will do:
mathematical modeling may prove wrong when the design is built.
By contrast, a computer program is built out of ideal
mathematical objects whose behavior is defined, not modeled
approximately, by abstract rules. When an if-statement follows a
while-statement, there is no need to study whether the if-
statement will draw power from the while-statement and thereby
distort its output, nor whether it could overstress the while-
statement and make it fail.
Despite being built from simple parts, computer programs are
incredibly complex. The program with 100,000 parts is as complex
as an automobile, though far easier to design.
While programs cost substantially less to write, market and sell
than automobiles, the cost of dealing with the patent system will
not be less. The same number of components will, on the average,
involve the same number techniques that might be patented.
The danger of a lawsuit
Under the current patent system, a software developer who wishes
to follow the law must determine which patents a program violates
and negotiate with each patent holder a license to use that
patent. Licensing may be prohibitively expensive, or even
unavailable if the patent is held by a competitor. Even
"reasonable" license fees for several patents can add up to make
a project infeasible. Alternatively, the developer may wish to
avoid using the patent altogether; but there may be no way around
The worst danger of the patent system is that a developer might
find, after releasing a product, that it infringes one or many
patents. The resulting lawsuit and legal fees could force even a
medium-size company out of business.
Worst of all, there is no practical way for a software developer
to avoid this danger - there is no effective way to find out
what patents a system will infringe. There is a way to try to
find out - a patent search - but searches are unreliable and in
any case too expensive to use for software projects.
Patent searches are prohibitively expensive
A system with a hundred thousand components can use hundreds of
techniques that might already be patented. Since each patent
search costs thousands of dollars, searching for all the possible
points of danger could easily cost over a million. This is far
more than the cost of writing the program.
The costs don't stop there. Patent applications are written by
lawyers for lawyers. A programmer reading a patent may not
believe that his program violates the patent, but a federal court
may rule otherwise. It is thus now necessary to involve patent
attorneys at every phase of program development.
Yet this only reduces the risk of being sued later - it does
not eliminate the risk. So it is necessary to have a reserve of
cash for the eventuality of a lawsuit.
When a company spends millions to design a hardware system, and
plans to invest tens of millions to manufacture it, an extra
million or two to pay for dealing with the patent system might be
bearable. However, for the inexpensive programming project, the
same extra cost is prohibitive. Individuals and small companies
especially cannot afford these costs. Software patents will put
an end to software entrepreneurs.
Patent searches are unreliable
Even if developers could afford patent searches, these are not a
reliable method of avoiding the use of patented techniques. This
is because patent searches do not reveal pending patent
applications (which are kept confidential by the Patent Office).
Since it takes several years on the average for a software patent
to be granted, this is a serious problem: a developer could begin
designing a large program after a patent has been applied for,
and release the program before the patent is approved. Only
later will the developer learn that distribution of the program
For example, the implementors of the widely-used public domain
data compression program "compress" followed an algorithm
obtained from the journal "IEEE Computer". (This algorithm is
also used in several popular programs for microcomputers,
including "PKZIP".) They and the user community were surprised to
learn later that patent number 4,558,302 had been issued to one
of the authors of the article. Now Unisys is demanding royalties
for using this algorithm. Although the program "compress" is
still in the public domain, using it means risking a lawsuit.
The Patent Office does not have a workable scheme for
classifying software patents. Patents are most frequently
classified by end results, such as "converting iron to steel;"
but many patents cover algorithms whose use in a program is
entirely independent of the purpose of the program. For example,
a program to analyze human speech might infringe the patent on a
speedup in the Fast Fourier Transform; so might a program to
perform symbolic algebra (in multiplying large numbers); but the
category to search for such a patent would be hard to predict.
You might think it would be easy to keep a list of the patented
software techniques, or even simply remember them. However,
managing such a list is nearly impossible. A list compiled in
1989 by lawyers specializing in the field omitted some of the
patents mentioned in this paper.
When you imagine an invention, you probably think of something
that could be described in a few words, such as "a flying machine
with fixed, curved wings" or "an electrical communicator with a
microphone and a speaker". But most patents cover complex
detailed processes that have no simple descriptions - often they
are speedups or variants of well-known processes that are
Most of these patents are neither obvious nor brilliant; they
are obscure. A capable software designer will "invent" several
such improvements in the course of a project. However, there are
many avenues for improving a technique, so no single project is
likely to find any given one.
For example, IBM has several patents (including patent number
4,656,583) on workmanlike, albeit complex, speedups for well-
known computations performed by optimizing compilers, such as
register coloring and computing the available expressions.
Patents are also granted on combinations of techniques that are
already widely used. One example is IBM patent 4,742,450, which
covers "shared copy-on-write segments." This technique allows
several programs to share the same piece of memory that
represents information in a file; if any program writes a page in
the file, that page is replaced by a copy in all of the programs,
which continue to share that page with each other but no longer
share with the file.
Shared segments and copy-on-write have been used since the
1960's; this particular combination may be new as a specific
feature, but is hardly an invention. Nevertheless, the Patent
Office thought that it merited a patent, which must now be taken
into account by the developer of any new operating system.
Obscure patents are like land mines: other developers are more
likely to reinvent these techniques than to find out about the
patents, and then they will be sued. The chance of running into
any one of these patents is small, but they are so numerous that
you cannot go far without hitting one. Every basic technique has
many variations, and a small set of basic techniques can be
combined in many ways. The patent office has now granted at
least 2000 software patents - no less than 700 in 1989 alone,
according to a list compiled by EDS. We can expect the pace to
accelerate. In ten years, programmers will have no choice but to
march on blindly and hope they are lucky.
Patent licensing has problems, too
Most large software companies are trying to solve the problem of
patents by getting patents of their own. Then they hope to
cross-license with the other large companies that own most of the
patents, so they will be free to go on as before.
While this approach will allow companies like Microsoft, Apple
and IBM to continue in business, it will shut new companies out
of the field. A future start-up, with no patents of its own,
will be forced to pay whatever price the giants choose to impose.
That price might be high: established companies have an interest
in excluding future competitors. The recent Lotus lawsuits
against Borland and the Santa Cruz Operation (although involving
an extended idea of copyright rather than patents) show how this
Even the giants cannot protect themselves with cross-licensing
from companies whose only business is to obtain exclusive rights
to patents and then threaten to sue. For example, consider the
New York-based Refac Technology Development Corporation,
representing the owner of the "natural order recalc" patent.
Contrary to its name, Refac does not develop anything except
lawsuits - it has no business reason to join a cross-licensing
compact. Cadtrak, the owner of the exclusive-or patent, is also
a litigation company.
Refac is demanding five percent of sales of all major spread-
sheet programs. If a future program infringes on twenty such
patents - and this is not unlikely, given the complexity of
computer programs and the broad applicability of many patents -
the combined royalties could exceed 100% of the sales price. (In
practice, just a few patents can make a program unprofitable.)
The fundamental question
According to the Constitution of the United States, the purpose
of patents is to "promote the progress of science and the useful
arts." Thus, the basic question at issue is whether software
patents, supposedly a method of encouraging software progress,
will truly do so, or will retard progress instead.
So far we have explained the ways in which patents will make
ordinary software development difficult. But what of the
intended benefits of patents: more invention, and more public
disclosure of inventions? To what extent will these actually
occur in the field of software?
There will be little benefit to society from software patents
because invention in software was already flourishing before
software patents, and inventions were normally published in
journals for everyone to use. Invention flourished so strongly,
in fact, that the same inventions were often found again and
In software, independent reinvention is commonplace
A patent is an absolute monopoly; everyone is forbidden to use
the patented process, even those who reinvent it independently.
This policy implicitly assumes that inventions are rare and
precious, since only in those circumstances is it beneficial.
The field of software is one of constant reinvention; as some
people say, programmers throw away more "inventions" each week
than other people develop in a year. And the comparative ease of
designing large software systems makes it easy for many people to
do work in the field. A programmer solves many problems in
developing each program. These solutions are likely to be
reinvented frequently as other programmers tackle similar
The prevalence of independent reinvention negates the usual
purpose of patents. Patents are intended to encourage inventions
and, above all, the disclosure of inventions. If a technique
will be reinvented frequently, there is no need to encourage more
people to invent it; since some of the developers will choose to
publish it (if publication is merited), there is no point in
encouraging a particular inventor to publish it - not at the
cost of inhibiting use of the technique.
Overemphasis of inventions
Many analysts of American and Japanese industry have attributed
Japanese success at producing quality products to the fact that
they emphasize incremental improvements, convenient features and
quality rather than noteworthy inventions.
It is especially true in software that success depends primarily
on getting the details right. And that is most of the work in
developing any useful software system. Inventions are a
comparatively unimportant part of the job.
The idea of software patents is thus an example of the mistaken
American preoccupation with inventions rather than products. And
patents will encourage this mistaken focus, even as they impede
the development work that actually produces better software.
By reducing the number of programmers engaged in software
development, software patents will actually impede innovation.
Much software innovation comes from programmers solving problems
while developing software, not from projects whose specific
purpose is to make inventions and obtain patents. In other words,
these innovations are byproducts of software development.
When patents make development more difficult, and cut down on
development projects, they will also cut down on the byproducts
of development - new techniques.
Could patents ever be beneficial?
Although software patents in general are harmful to society as a
whole, we do not claim that every single software patent is
necessarily harmful. Careful study might show that under certain
specific and narrow conditions (necessarily excluding the vast
majority of cases) it is beneficial to grant software patents.
Nonetheless, the right thing to do now is to eliminate all
software patents as soon as possible, before more damage is done.
The careful study can come afterward.
Clearly software patents are not urgently needed by anyone
except patent lawyers. The pre-patent software industry had no
problem that was solved by patents; there was no shortage of
invention, and no shortage of investment.
Complete elimination of software patents may not be the ideal
solution, but it is close, and is a great improvement. Its very
simplicity helps avoid a long delay while people argue about
If it is ever shown that software patents are beneficial in
certain exceptional cases, the law can be changed again at that
time - if it is important enough. There is no reason to
continue the present catastrophic situation until that day.
Software patents are legally questionable
It may come as a surprise that the extension of patent law to
software is still legally questionable. It rests on an extreme
interpretation of a particular 1981 Supreme Court decision,
"Diamond vs. Deihr". (See "Legally Speaking" in "Communications
of the ACM", August 1990.)
Traditionally, the only kinds of processes that could be
patented were those for transforming matter (such as, for
transforming iron into steel). Many other activities which we
would consider processes were entirely excluded from patents,
including business methods, data analysis, and "mental steps."
This was called the "subject matter" doctrine.
"Diamond vs. Deihr" has been interpreted by the Patent Office as
a reversal of this doctrine, but the court did not explicitly
reject it. The case concerned a process for curing rubber - a
transformation of matter. The issue at hand was whether the use
of a computer program in the process was enough to render it
unpatentable, and the court ruled that it was not. The Patent
Office took this narrow decision as a green light for unlimited
patenting of software techniques, and even for the use of
software to perform specific well-known and customary activities.
Most patent lawyers have embraced the change, saying that the
new boundaries of patents should be defined over decades by a
series of expensive court cases. Such a course of action will
certainly be good for patent lawyers, but it is unlikely to be
good for software developers and users.
One way to eliminate software patents
We recommend the passage of a law to exclude software from the
domain of patents. That is to say that, no matter what patents
might exist, they would not cover implementations in software;
only implementations in the form of hard-to-design hardware would
be covered. An advantage of this method is that it would not be
necessary to classify patent applications into hardware and
software when examining them.
Many have asked how to define software for this purpose - where
the line should be drawn. For the purpose of this legislation,
software should be defined by the characteristics that make
software patents especially harmful:
o Software is built from ideal infallible mathematical
components, whose outputs are not affected by the components
they feed into.
Ideal mathematical components are defined by abstract rules,
so that failure of a component is by definition impossible.
The behavior of any system built of these components is
likewise defined by the consequences of applying the rules
step by step to the components.
o Software can be easily and cheaply copied.
Following this criterion, a program to compute prime numbers
is a piece of software. A mechanical device designed
specifically to perform the same computation is not
software, since mechanical components have friction, can
interfere with each other's motion, can fail, and must be
assembled physically to form a working machine.
Any piece of software needs a hardware platform in order to
run. The software operates the features of the hardware in
some combination, under a plan. Our proposal is that
combining the features in this way can never create
infringement. If the hardware alone does not infringe a
patent, then using it in a particular fashion under control
of a program should not infringe either. In effect, a
program is an extension of the programmer's mind, acting as
a proxy for the programmer to control the hardware.
Usually the hardware is a general purpose computer, which
implies no particular application. Such hardware cannot
infringe any patents except those covering the construction
of computers. Our proposal means that, when a user runs
such a program on a general purpose computer, no patents
other than those should apply.
The traditional distinction between hardware and software
involves a complex of characteristics that used to go hand
in hand. Some newer technologies, such as gate arrays and
silicon compilers, blur the distinction because they combine
characteristics associated with hardware with others
associated with software. However, most of these
technologies can be classified unambiguously for patent
purposes, either as software or as hardware, using the
criteria above. A few gray areas may remain, but these are
comparatively small, and need not be an obstacle to solving
the problems patents pose for ordinary software development.
They will eventually be treated as hardware, as software, or
as something in between.
Fighting patents one by one
Until we succeed in eliminating all patenting of software, we
must try to overturn individual software patents. This is very
expensive and can solve only a small part of the problem, but
that is better than nothing.
Overturning patents in court requires prior art, which may not
be easy to find. The League for Programming Freedom will try to
serve as a clearing house for this information, to assist the
defendants in software patent suits. This depends on your help.
If you know about prior art for any software patent, please send
the information to the League at the address given above.
If you work on software, you can personally help prevent
software patents by refusing to cooperate in applying for them.
The details of this may depend on the situation.
Exempting software from the scope of patents will protect
software developers from the insupportable cost of patent
searches, the wasteful struggle to find a way clear of known
patents, and the unavoidable danger of lawsuits.
If nothing is changed, what is now an efficient creative
activity will become prohibitively expensive. To picture the
effects, imagine if each square of pavement on the sidewalk had
an owner, and pedestrians required a license to step on it.
Imagine the negotiations necessary to walk an entire block under
this system. That is what writing a program will be like if
software patents continue. The sparks of creativity and
individualism that have driven the computer revolution will be
The League for Programming Freedom is a grass-roots organization
of professors, students, businessmen, programmers and users
dedicated to bringing back the freedom to write programs. The
League is not opposed to the legal system that Congress intended
- copyright on individual programs. Our aim is to reverse the
recent changes made by judges in response to special interests,
often explicitly rejecting the public interest principles of the
The League works to abolish the new monopolies by publishing
articles, talking with public officials, boycotting egregious
offenders, and in the future may intervene in court cases. On
May 24, 1989, the League picketed Lotus headquarters on account
of their lawsuits, and then again on August 2, 1990. These
marches stimulated widespread media coverage for the issue. We
welcome suggestions for other activities, as well as help in
carrying them out.
Membership dues in the League are $42 per year for programmers,
managers and professionals; $10.50 for students; $21 for others.
Please give more if you can. The League's funds will be used for
filing briefs; for printing handouts, buttons and signs; whatever
will persuade the courts, the legislators, and the people. You
may not get anything personally for your dues - except for the
freedom to write programs. The League is a non-profit
corporation, but not considered a tax-exempt charity. However,
for those self-employed in software, the dues can be a business
The League needs both activist members and members who only pay
their dues. We also greatly need additional corporate members;
contact us for information.
If you have any questions, please write to the League, phone +1
617 621-7084, or send Internet mail to email@example.com.
Jack Larsen, President
Dean Anderson, Secretary
Steve Sisak, Treasurer
Jack Larsen can be contacted at (708) 698-1160; Fax (708) 698-
6221. The adress is:
League for Programming Freedom
1 Kendall Square #143
Cambridge, Massachusetts 02139
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