The Revised Maclisp ManualThe PitmanualPage M-1
Published by HyperMeta Inc.
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Front Matter
Sunday Morning Credits
Legal Notices

History of the Pitmanual

How It Started

[Thumbnail photo of PDP-10]

This got started because I was working in the MACSYMA group, part of the MIT Laboratory for Computer Science (LCS), and I had to ask a lot of questions about MACLISP because the existing documentation was ineffective. Fortunately, Guy Steele and JonL White shared an office with me, and many other knowledgeable people were not far away. (See the credits for a full list.)

I took a lot of notes, and had started to organize them when I learned about the TeX typesetting system. It had powerful capabilities not present in other typesetting systems of the day, so I was trying to invent ways to use it. On the other hand, it was syntactically ugly, so I didn't want to use it directly. This led me to think of it as a possible target to “compile” my notes into. In that way, I could write the notes in plaintext and have them come out prettily. This manual was originally as much an experiment in using TeX as it was in doing anything with MACLISP.

It occurred to me at some point that if I were to keep the notes to myself, it would be a good source of job security for me. It seemed that there was a lot of trivia about MACLISP that most people didn't know, and I had observed that there were already areas of Computer Science where people made money by knowing obscure facts and being able to act on them when others couldn't. Being the keeper of such information seemed potentially lucrative.

But it troubled me to see people programming in a language they thought they understood while I knew that the real language was really very different—for every operator that people thought they understood, there seemed to be some mysterious option variable capable of changing its meaning. (See, for example, CAR or ERRSET.)

At some point I decided that it was more important that people just know how things really worked. I hoped there would still be a way to build a career even if I shared this seemingly valuable information.

So I went about compiling what would become The Revised Maclisp Manual, also known as The Pitmanual.

Follow The Money

At the time, I really didn't understand the nature of copyright—who had the right to it, what exactly it protected, etc. At the time, it seemed a vague badge of honor, but one that at some point became an administrative obstacle to publication. I was anxious to get the manual published, and not really aware that I might be leaving money on the table by not pursuing my rights. That was an expensive lesson.

The Pitmanual had been written on my own initiative and with many, many hours of my own effort. For most of the time while writing it, I was an MIT student, paying tuition. I was not paid staff. For a brief interval while a student, I got some amount of income from the MIT Undergraduate Research Opportunities Program (UROP), but that was for programming work related to MACSYMA, not for anything related to the writing of the manual. And toward the end I was an employee of the AI Lab working on the Programmer's Apprentice Project using Lisp Machines. That also had nothing to do with MACLISP, and so I was forced to find free time on top of the regular work I had to do in order to get it finished.

Since that time, I have come to understand that people are generally entitled to the copyright on works they author, unless paid to do the authoring. As such, I now believe I could have and should have claimed copyright.

I recall worrying that somehow the fact that a lot of people had answered questions or contributed small pieces of text (some of which I used, some of which I didn't) might somehow mean I couldn't have any copyright claim.

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I have since come to understand that such issues are routine in the creation of any well-researched work, and do not automatically yield one's claim. (A case in point is that I myself contributed an entire chapter to the Second Edition of Common Lisp: The Language, and yet Guy Steele didn't lose his right to copyright that entire book.)

The people in the MIT LCS publications office probably assumed, especially because I was an MIT employee at the time of publication, that the document was the result of paid activity. So probably it didn't occur to them that there was anything odd about asking me to sign over the copyright. The whole business of signing over copyright seemed odd to me, but I couldn't think of anything to do to prove the work had been mine. And I didn't have the money to go hire a lawyer. So I just signed.

In retrospect, I'm quite convinced the answer to the copyright problem would have been to simply delay publishing until the matter was resolved to my satisfaction. MIT had no way to compel me to publish it since MIT had not paid me to write it. I, on the other hand, had the right to withhold the finished work. Since there was interest in the document at the time, that would have put me in a strong bargaining position. But I didn't know that. So I didn't bargain. I just gave in.

Money Matters

Since I originally thought MIT wasn't profiting, it seemed at first not so bad that I wasn't. It was a culture in which people indulged the illusion of family, all contributing for each other, everyone benefiting equally. But that illusion was spoiled when I found that MIT had made the equivalent of my first year's salary in net profit on the manual, and that I had received none of that.

A university takes over for family in one's growth. It feeds you, houses you, takes care of you. It's like your substitute family. It's sometimes hard to recognize that, unlike family, the reason it does these things is not that it loves you but that you're paying it to. And if one doesn't recognize this critical difference, it's easy to unconsciously expect other family-like attributes of it, such as the idea that it will share its good fortune with you.

But universities are not family. They are not even people. They are businesses. Unlike people, and especially unlike one's family, businesses generally do not voluntarily do favors for people been loyal to or benefited them. Businesses generally do what they are contractually obligated to do, rarely more or less. So since I had signed away my copyright to MIT, it assumed it owed me nothing. And that was simply that.

Had I insisted on a different arrangement, MIT might well have been fine with that. Or perhaps, if they were not interested in another arrangement, I could have gone to another publisher. But I didn't. And so when money came in, it didn't go to me. Years of work were no longer relevant. Having done something for my community was no longer relevant. All that mattered was that I had no contract entitling me to the money, and so the money was not mine.

I had some naive perceptions about how the world worked, and as a result I did some things that didn't turn out to be in my own best interest. The story doesn't flatter me. Frankly, even to me, it sounds a bit like whining to tell it. But I tell it even at the risk that you might get that impression of me because I think stories like this can be instructive, and I would like others to have a chance to learn from my mistakes.

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I should have acquired a better understanding of copyright. I should have insisted on an appropriate financial arrangement. Failing to do that was a mistake that I have paid for in real, measurable economic terms.

This kind of thing matters especially in these days where advocates of so-called “free software” tell programmers that they should just contribute their efforts freely and that somehow there will be “plenty for all”. That's an oversimplistic story. The benefit generally accrues disproportionately, and very often not with the content creator. People who think otherwise are often just gambling. And they say of gambling that if you don't know who the fool at the table is, it's you.

Sunday Morning Edition

After a few years, sales of The Revised Maclisp Manual (Saturday Evening Edition) in hardcopy by MIT eventually fell off, and I was worried about The Pitmanual disappearing from the historical record. Fortunately, I was able to enlist the help of Rod Brooks, then head of MIT's AI Lab (and incidentally also a co-founder of iRobot), who had a keen interest in historical preservation as well.

Being an experienced administrator, Rod knew just the right thing to do to help: He wrote the MIT lawyers a very nice letter explaining to them just how little value my writings had. That may sound odd, but it was exactly what the lawyers needed to hear, since the kind of value they are primarily obliged to care about is economic value, not historical value. And since the lingering value was historical, that meant the lawyers, as guardians of MIT's economic interests, could rest easy.

Of course, MIT stopped short of returning the copyright ownership itself to me, but with Rod's able assistance, for which I am quite grateful, they were persuaded to at least to grant me the unrestricted right to produce my own derivative works, enabling me to produce this webbed document you're reading now.

According to the terms of use I was granted, I am legally required to suffer the minor indignity of acknowledging that MIT still owns and asserts the copyright on The Revised Maclisp Manual (Saturday Evening Edition), and that my use of that work is merely through a grant of non-exclusive license. I do hereby acknowledge that fact, and, having done so, I assume I have discharged that obligation. Fortunately, among the rights granted were those necessary to produce this document. For that I am certainly grateful.

I do assert copyright on this webbed document. It is derived from the original work, but involved substantial additional effort to produce. The webbed version (dubbed the Sunday Morning Edition) is also my own work, and again not something I got paid to do. I have produced it out of a desire for historical completeness.

Changes in This Edition

This webbed version has made the following substantive changes:

  • Fixes many typos.
  • Adds important indexing keys.
  • Re-organizes the indexes for better lookup.
  • Adds useful historical notes to accommodate the fact that MACLISP is no longer a modern language.
  • Adds HTML markup and hyperlinking.
  • Adds some dictionary entries that were missing or suppressed in the original version.
  • Adds notes on converting Maclisp to Common Lisp.

Additional work has also been done to restore some files for which online sources had gone missing. This won't reflect itself as a visible change from the hardcopy, but will be important to those who had stray (albeit unauthorized) copies of my source files recovered from old backup tapes.


You may read this edition of The Revised Maclisp Manual at this web site free of charge, but you are not authorized to make copies of this edition of The Revised Maclisp Manual (Sunday Morning Edition).

The primary reason (not that any is legally required, but just in case you're curious) is that I want to be able to fix typos in one place without doing complicated versioning. If other copies of this document were permitted, it would confuse and complicate my update and delivery strategy, as well as my ability to update my advertising.

It is possible that at some point later, if things seem stable, I will be able to repackage this document more like the Common Lisp HyperSpec so that people can make locally cached copies. But for now that is not how things are, so for now you must read this document here.

For further details, see “Important Legal Notices

The Revised Maclisp Manual (Sunday Morning Edition)
Published Sunday, December 16, 2007 06:17am EST, and updated Sunday, July 6, 2008.
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