Hackers, Heroes of the Computer Revolution - Steven Levy (top books to read txt) 📗

saw what were once plain old blackboard Arabic numbers coming back as the numerals the Romans had hacked with.

 

In fact it was Jack Dennis who suggested to Samson that there were considerable uses for the TX-O’s ability to send noise to the audio speaker. While there were no built-in controls for pitch, amplitude, or tone character, there was a way to control the speaker—sounds would be emitted depending on the state of the fourteenth bit in the eighteen-bit words the TX-0 had in its accumulator in a given microsecond. The sound was on or off depending on whether bit fourteen was a one or zero. So Samson set about writing programs that varied the binary numbers in that slot in different ways to produce different pitches.

 

At that time, only a few people in the country had been experimenting with using a computer to output any kind of music, and the methods they had been using required massive computations before the machine would so much as utter a note, Samson, who reacted with impatience to those who warned he was attempting the impossible, wanted a computer playing music right away. So he learned to control that one bit in the accumulator so adeptly that he could command it with the authority of Charlie Parker on the saxophone. In a later version of this music compiler, Samson rigged it so that if you made an error in your programming syntax, the Flexowriter would switch to a red ribbon and print “To err is human to forgive divine.”

 

When outsiders heard the melodies of Johann Sebastian Bach in a single-voice, monophonic square wave, no harmony, they were universally unfazed. Big deal! Three million dollars for this giant hunk of machinery, and why shouldn’t it do at least as much as a five-dollar toy piano? It was no use to explain to these outsiders that Peter Samson had virtually bypassed the process by which music had been made for eons. Music had always been made by directly creating vibrations that were sound. What happened in Samson’s program was that a load of numbers, bits of information fed into a computer, comprised a code in which the music resided. You could spend hours staring at the code, and not be able to divine where the music was. It only became music while millions of blindingly brief exchanges of data were taking place in the accumulator sitting in one of the metal, wire, and silicon racks that comprised the TX-0. Samson had asked the computer, which had no apparent knowledge of how to use a voice, to lift itself in song—and the TX-0 had complied.

 

So it was that a computer program was not only metaphorically a musical composition—it was LITERALLY a musical composition! It looked like—and was—the same kind of program which yielded complex arithmetical computations and statistical analyses.

These digits that Samson had jammed into the computer were a universal language which could produce ANYTHING—a Bach fugue or an anti-aircraft system.

 

Samson did not say any of this to the outsiders who were unimpressed by his feat. Nor did the hackers themselves discuss this—it is not even clear that they analyzed the phenomenon in such cosmic terms. Peter Samson did it, and his colleagues appreciated it, because it was obviously a neat hack. That was justification enough.

 

*

 

To hackers like Bob Saunders—balding, plump, and merry disciple of the TX-0, president of TMRC’s S&P group, student of systems—

it was a perfect existence. Saunders had grown up in the suburbs of Chicago, and for as long as he could remember the workings of electricity and telephone circuitry had fascinated him. Before beginning MIT, Saunders had landed a dream summer job, working for the phone company installing central office equipment, He would spend eight blissful hours with soldering iron and pliers in hand, working in the bowels of various systems, an idyll broken by lunch hours spent in deep study of phone company manuals. It was the phone company equipment underneath the TMRC

layout that had convinced Saunders to become active in the Model Railroad Club.

 

Saunders, being an upperclassman, had come to the TX-0 later in his college career than Kotok and Samson: he had used the breathing space to actually lay the foundation for a social life, which included courtship of and eventual marriage to Marge French, who had done some non-hacking computer work for a research project. Still, the TX-0 was the center of his college career, and he shared the common hacker experience of seeing his grades suffer from missed classes. It didn’t bother him much, because he knew that his real education was occurring in Room 240

of Building 26, behind the Tixo console. Years later he would describe himself and the others as “an elite group. Other people were off studying, spending their days up on four-floor buildings making obnoxious vapors or off in the physics lab throwing particles at things or whatever it is they do. And we were simply not paying attention to what other folks were doing because we had no interest in it. They were studying what they were studying and we were studying what we were studying. And the fact that much of it was not on the officially approved curriculum was by and large immaterial.”

 

The hackers came out at night. It was the only way to take full advantage of the crucial “off-hours” of the TX-0. During the day, Saunders would usually manage to make an appearance in a class or two. Then some time spent performing “basic maintenance”—things like eating and going to the bathroom. He might see Marge for a while. But eventually he would filter over to Building 26. He would go over some of the programs of the night before, printed on the nine-and-a-half-inch-wide paper that the Flexowriter used. He would annotate and modify the listing to update the code to whatever he considered the next stage of operation. Maybe then he would move over to the Model Railroad Club, and he’d swap his program with someone, checking simultaneously for good ideas and potential bugs. Then back to Building 26, to the Kluge Room next to the TX-0, to find an off-line Flexowriter on which to update his code. All the while he’d be checking to see if someone had canceled a one-hour session on the machine; his own session was scheduled at something like two or three in the morning. He’d wait in the Kluge Room, or play some bridge back at the Railroad Club, until the time came.

 

Sitting at the console, facing the metal racks that held the computer’s transistors, each transistor representing a location that either held or did not hold a bit of memory, Saunders would set up the Flexowriter, which would greet him with the word “WALRUS.” This was something Samson had hacked, in honor of Lewis Carroll’s poem with the line “The time has come, the Walrus said …” Saunders might chuckle at that as he went into the drawer for the paper tape which held the assembler program and fed that into the tape reader. Now the computer would be ready to assemble his program, so he’d take the Flexowriter tape he’d been working on and send that into the computer. He’d watch the lights go on as the computer switched his code from “source” (the symbolic assembly language) to “object” code (binary), which the computer would punch out into another paper tape. Since that tape was in the object code that the TX-0 understood, he’d feed it in, hoping that the program would run magnificently.

 

There would most probably be a few fellow hackers kibitzing behind him, laughing and joking and drinking Cokes and eating some junk food they’d extracted from the machine downstairs.

Saunders preferred the lemon jelly wedges that the others called “lemon gunkies.” But at four in the morning, anything tasted good. They would all watch as the program began to run, the lights going on, the whine from the speaker humming in high or low register depending on what was in Bit 14 in the accumulator, and the first thing he’d see on the CRT display after the program had been assembled and run was that the program had crashed. So he’d reach into the drawer for the tape with the FLIT debugger and feed THAT into the computer. The computer would then be a debugging machine, and he’d send the program back in. Now he could start trying to find out where things had gone wrong, and maybe if he was lucky he’d find out, and change things by putting in some commands by flicking some of the switches on the console in precise order, or hammering in some code on the Flexowriter.

Once things got running—and it was always incredibly satisfying when something worked, when he’d made that roomful of transistors and wires and metal and electricity all meld together to create a precise output that he’d devised—he’d try to add the next advance to it. When the hour was over—someone already itching to get on the machine after him—Saunders would be ready to spend the next few hours figuring out what the heck had made the program go belly-up.

 

The peak hour itself was tremendously intense, but during the hours before, and even during the hours afterward, a hacker attained a state of pure concentration. When you programmed a computer, you had to be aware of where all the thousands of bits of information were going from one instruction to the next, and be able to predict—and exploit—the effect of all that movement.

When you had all that information glued to your cerebral being, it was almost as if your own mind had merged into the environment of the computer. Sometimes it took hours to build up to the point where your thoughts could contain that total picture, and when you did get to that point, it was such a shame to waste it that you tried to sustain it by marathon bursts, alternatively working on the computer or poring over the code that you wrote on one of the off-line Flexowriters in the Kluge Room. You would sustain that concentration by “wrapping around” to the next day.

 

Inevitably, that frame of mind spilled over to what random shards of existence the hackers had outside of computing. The knife-and-paintbrush contingent at TMRC were not pleased at all by the infiltration of Tixo-mania into the club: they saw it as a sort of Trojan horse for a switch in the club focus, from railroading to computing. And if you attended one of the club meetings held every Tuesday at five-fifteen, you could see the concern: the hackers would exploit every possible thread of parliamentary procedure to create a meeting as convoluted as the programs they were hacking on the TX-0. Motions were made to make motions to make motions, and objections ruled out of order as if they were so many computer errors. A note in the minutes of the meeting on November 24, 1959, suggests that “we frown on certain members who would do the club a lot more good by doing more S&P-ing and less reading Robert’s Rules of Order.” Samson was one of the worst offenders, and at one point, an exasperated TMRC member made a motion “to purchase a cork for Samson’s oral diarrhea.”

 

Hacking parliamentary procedure was one thing, but the logical mind-frame required for programming spilled over into more commonplace activities. You could ask a hacker a question and sense his mental accumulator processing bits until he came up with a precise answer to the question you asked. Marge Saunders would drive to the Safeway every Saturday morning in the Volkswagen and upon her return ask her husband, “Would you like to help me bring in the groceries?” Bob Saunders would reply, “No.” Stunned, Marge would drag in