BASIC

== Circulating Programs in Print ==

== Programs in Human Memory ==

In today's computing context, it is hard enough to remember programs being transmitted on physical media such as floppy disks and cassette tapes. The notion that programs would routinely be published in print and typed by users is even more alien. But at least there is material evidence that programs were transmitted in this way, and people today can somehow relate to this practice because they are still invited to key in code snippets of different sorts that are printed in books on programming.

There is an even stranger way that programs, particularly short ones such as BASIC one-liners, got from computer to computer and from person to person: By being memorized. While it may not have been a ''Fahrenheit 451'' situation with the world's great computer programs preserved by a dedicated few, it was common for people who knew a bit of programming to keep a one-liner, or even a handful of short programs, in mind to type into a friend's computer or one at school.

The dream of having total recall of a massive computer program manifests itself in science fiction. In Cory Doctorow's story "0wnz0red," the main character, Murray, is initially a fat slob who, after the death of his only friend Liam, has spiraled downwards personally and in terms of code quality. After Liam returns, having actually hacked his body and mind into perfection when he was near death, Murray is provided with similarly superhuman abilities, including the ability to exactly remember large amounts of English text: "... generating a 4,096 bit key that he could remember was going to be damned hard, but then he closed his eyes and recalled, with perfect clarity, the first five pages of documentation he'd written for the API. His fingers rattled on the keys at speed, zero typos." The keyboard isn't essential to this process: Later, while hooded and being interrogated, Murray recites the entire key.

In the culminating moment of "0wnz0red," it is revealed that while Murray apparently can't easily memorize a random sequence of characters, his powers of recall extend beyond human language: "once he had the laptop open and began to rekey the entire codebase, the eidetic rush of perfect memory dispelled all his nervousness, leaving him cool and calm as the sun set over the Mission." Murray is human enough that he cannot recall an arbitrary 4KB, but enough of a savant, or a machine, that he can perfectly remember documentation that he wrote -- and, as is dramatically revealed, he's also an extreme enough programmer that he can retype the code he and Liam developed together.

Doctorow's story makes it clear that the ability to memorize a large program is a superpower; that is, it is not an ordinary human ability and it is also an ability that is awesome, desirable, and elite. At the same time, the story's treatment of the human body and mind as comptuerlike, capable of being mastered by a programmer and owned (or even 0wnz0red) by an adversary, is consistent with the idea that memorizing code is slaving one mind's to the machine, treating it as a storage peripheral.

The idea that a page of code is easier to memorize than a random page of characters is supported by experimental studies. In an effort to better understand how people comprehend computer programs -- which has ramifications for programmer efficiency -- studies of program memorization were undertaken beginning in the mid-1970s. In 1976 Ben Shneiderman reported a statistically significant difference between subjects of different ability levels attempting to memorize a FORTRAN program and a series of valid FORTRAN statements in scrambled order, "leading us to the conclusion that the structure of a program facilitates comprehension and memorization." (p. 127) Part of the motivation for this study was the cognitive psychology literature on remembering sentences.

Ruven Brooks published a more elaborate theory of program comprehension in 1983. This is one in which a programmer reconstructs knowledge about the real-world domains that the program models, developing an initially underspecified hypothesis and refining and elaborating it "based on information extracted from the program text and other documentation." (p. 543) Brooks posited the useful idea that certain lines were "beacons," specially indicating program structures and operations. (p. 548) But his theory is otherwise difficult to apply to 10 PRINT .... Brooks lists seven internal and five external "indicators for the meaning of a program," such as "Indentation or pretty-printing" and "Flowcharts." (p. 551) None are present for the program that is the focus of this book. More fundamentally, Brooks's model is for programs that simulate business processes, not computer programs in general. He introduced a shipping domain in his paper, but then noted that "If the task is to implement a general algorithm for a general purpose routine, say a matrix inversion subroutine, there will be no domain corresponding to the original domain of cargoes and routes." (p. 545) In fact, the problem is not just with abstract processes and mathematical routines. Brooks's model cannot directly apply to any creative production that is done by programming the computer, unless it happens to also have a business-style real-world domain. What is the "cargoes and routes"-style domain of games, recreational programming, art, music, obfuscated code, or demos and intros from the demoscene?

Brooks's concept of beacons was used in another memorization study by Susan Widenbeck, published in 1986, in which a comprehension model with top-down and bottom-up aspects was introduced. (Note: In both these studies, the programs were printed out and handed to subjects. None were shown programs on a screen.) Widenbeck found that beacon lines were recalled more often by experienced programmers. She also noted, "Memorizing a program is a very unusual programming task, and it is possible that it changed the subjects' normal program comprehension strategies and procedures." (p. 705) She found that program memorization was not like the memorization of text: "If subjects were taking a strictly linear, or text-reading, approach to understanding the program, we would expect the lines near the beginning of the program to be better remembered ... this was not the case." (p. 707) At the same time, she made analogies to the reading of texts in describing how her subjects read programs: "Using beacons to understand a program seems to be something like skimming an English text. They help to figure out the general, high-level function, but they do not contribute to a detailed understanding of the code ..." (p. 708)

Shneiderman's early acknowledgement that programs can be memorized is significant; his result, furthermore, shows that the memorization of programs relates to the memorization of language in some important ways. But there are differences between this study's perspective and the consideration of how BASIC one-liners are memorized. Shneiderman focuses on comprehension and uses memorization as a measure of comprehension; although it seems evident from all of these studies that two are deeply connected, memorization is nevertheless being considered along the way to understanding something else. Shneiderman's study is about the short-term memorization of programs of about 20 lines, assigned as a task. For instance, Shneiderman cites the famous paper on short-term memory, Miller's 1956 "The magical number seven, plus or minus two," and discusses how his results may be consistent with the ones in that paper.

The memorization of BASIC one-liners is more long-term, is done for fun, and of course involves shorter programs. This type of memorization will have certain things in common with the type done in these memorization studies, but it may also relate to the way people memorize jokes, proverbs, and other other texts. These studies do at least show how people can remember key statements (beacons) and the high-level workings of a program without memorizing it character by character. The appearance of program variants that work identically but are written differently is consistent with studies on and theories of program memorization.

== Works Cited ==

Brooks, Ruven. "Towards a theory of the comprehension of computer programs." International Journal of Man-Machine Studies 18. pp. 543-554. 1983.

Doctorow, Cory. "0wnz0red." Salon.com. August 28, 2002.

Shneiderman, Ben. "Exploratory Experiments in Programmer Behavior." International Journal of Computer and Information Sciences, Vol. 5, No. 2., 1976, pp. 123-143.

Widenbeck, Susan. "Beacons in computer program comprehension." International Journal of Man-Machine Studies 25. pp. 697-709. 1986.