Many programs in the 1950s were written in “machine language,” the actual instructions in the “natural language” of the computer. Commands had to be specified in exhaustive detail; there was a one-to-one correspondence between each line of the program and each instruction to the machine. Working in machine language could be tedious, and mistakes were difficult to find and correct. But it gave programmers a strong sense of identification with the machine. Computer programming was still so new that few people understood its intricacies. Many who worked in the more traditional sciences ignored (or dismissed) those who were exploring computers as a science.
Lincoln Laboratory was proving to be a perfect incubator for the kind of genius that ARPA would need to push computing into the interactive, and interconnected, age. It had already turned into a breeding ground for some of the most important early work in computing and networking. Many of its alumniâamong them, Licklider, Roberts, Heart, and others still to comeâwould play crucial roles in the design and development of the ARPA network. In the early days, computer programmers at Lincoln were poorly regarded. Only full-fledged physicists and mathematicians were allowed on the research staff, and many programmers left Lincoln as a result. But Heart broke through the prejudice. He started out as a graduate student programmer, became a staff member, and before long he was running a group.
Heart also disregarded the rules. He had little tolerance for professional delineations and didn't take titles too seriously. When a young programmer named Dave Walden came to work at Lincoln, he was hired on with the title of technical assistant. The fact that this was not a staff-level post was clearly indicated on his security badge. Titles were important at Lincoln, and among other things, the badge kept him out of staff-member seminars. Ignoring all that, and flouting the protocol that assigned nonstaff to the least-desirable work space, Heart set Walden up in an office with one of Walden's mentors, a young MIT graduate named Will Crowther. Crowther was a physicist turned computer scientist.
In the late 1950s and early 1960s, Heart, Crowther, and others close to them worked on one groundbreaking project after another. In time, Heart and his team at Lincoln became experts at connecting a variety of measuring devices to computers via phone lines for information gathering. This in turn made them experts in building real-time computing systems.
When a group of Heart's colleagues left to start MITRE Corporation in 1958, Heart remained firmly moored to Lincoln, partly because he had always disliked change and partly because he loved what he was doing. He couldn't imagine ever having a more interesting job or a more talented group with which to work.
In the summer of 1965, Heart met Danny Bobrow, who had been working on artificial intelligence at BBN. Bobrow suggested to Heart that he leave Lincoln for a job at BBN, overseeing a project to introduce computer technology into hospitals. When Heart declined, Dick Bolt stepped in.
One of the reasons the principals at BBN were anxious to woo Heart was that he had fruitful experience in putting together systems that worked efficiently in the field. The company needed someone like that. For all its innovation, BBN hadn't been very successful at turning its ideas into functioning, usable systems. “The culture at BBN at the time was to do interesting things and move on to the next interesting thing,” said one former employee. There was more incentive to come up with interesting ideas and explore them than to try to capitalize on them once they had been developed.
Bolt invited Heart to his house. They had more meetings at BBN. They met at the local Howard Johnson's. Heart remained reluctant, but there were aspects of the BBN job that appealed to him. Like Licklider, Heart had always held what he described as a “dogooder's” view: Heart believed computers and technology could help society. Wedded as it was to the military, Lincoln Lab had never gone very far afield of the Air Force's needs. In fact, the lab's narrow focus had precipitated the departure of people like Ken Olsen and Wes Clark, who left to build computers. Heart was also interested in the application of computers to the life sciences, and Bolt let him know he would have the opportunity to pursue that interest at BBN. Moreover, a friend of Heart's from Yonkers, Jerry Elkind, was at BBN, and Heart respected Elkind quite a bit. “It also occurred to me,” Heart admitted, “that there was a chance I could make some money at a private corporation.”
In the end, Bolt convinced him to take the job, but by the time Heart got to BBN, the company's computer research was being carried out by two separate divisions: information sciences and computer systems. As a general rule, those with Ph.D.'s worked in the information sciences, or research, division, while those without Ph.D.'s worked in the computer systems division. One member of the information sciences division described the computer systems division as consisting of a bunch of guys with soldering irons. In other words, they just got things built, while those in the research division considered themselves more concerned with inventing the future. There was not much cross-pollination between the two groups. They worked in separate buildings, divided by a narrow, glass-enclosed footbridge. It wasn't animosity, exactly, that separated them, nor was it rivalry. Each was aware of the other's limitations, resulting in a conspicuous lack of interest in what happened in the other camp. Frank Heart was a systems guy through and through.
When ARPA's request for proposals to build the IMP arrived at BBN in August 1968, the company had thirty days to respond. Jerry Elkind, who now was Heart's boss, was in charge of both computer divisions. He thought BBN should bid, and he thought Heart was the best person at the company to manage it. Since the demise of the hospital computer project shortly after he had arrived, Heart had been searching for a long-term project in which to immerse himself. Moreover, Heart probably had the most experience in building the kind of computer system that ARPA was seeking. Nonetheless, when Elkind suggested he take it on, Heart was typically cautious.
Heart could be difficult to interpret at first. Alex McKenzie, who worked for Heart on and off for twenty-seven years, recalled the first time he encountered his new bossâfrom the other end of a hallway. Heart was speaking in a loud, high-pitched voice to someone else and seemed agitated. “He was really yelling, and I thought it must be trouble,” McKenzie recalled. “Then later I found out it was simply enthusiasm.” A few years later, while on an airplane with Heart, McKenzie finally told him about his initial impression. Heart raised his eyebrows. “YELLING?!” Heart yelled, his voice reaching for its trademark falsetto, loud enough to attract the attention of everyone around them. “I don't yell!” Not, that is, when angry. “When he's angry he gets very quiet,” McKenzie said.
Meetings with Heart occasionally involved a lot of shouting. “And then the next day it turns out he's heard what you said through all the yelling and shouting,” recalled another longtime employee. “If you were willing to put up with the yelling and shouting, he made things come out right, unlike most people who yell and shout.” Heart had prodigious energy, which made it difficult for him to sit still for more than a few minutes at a time. He was most relaxed when he was at home, working in his basement woodworking shop, where he whistled long complex pieces of music flawlessly, seldom aware that he was doing so. When things were tense or uncertain, he bit his fingernails or drummed his fingers on tabletops.
Heart was intensely loyal to the people who worked for him and they in turn were loyal to him. He was also nurturing, not just toward his three children (he happily took on many child-care chores not expected of husbands in those days) but also toward his employees. At the same time, he took a lot of things personally, particularly when people left his group to go work somewhere else, even if it was only across the hall to another division.
One of Heart's greatest strengths was making certain that jobs he signed up for really got done, and in taking on the ARPA job he was concerned about the risk of committing the company to something it might not be able to accomplish. The project was packed with uncertainties and unexplored technology. Heart found it difficult to gauge exactly what was involved. There wasn't time to do the kind of detailed planning he'd like to do on a systems software project, such as estimating the number of lines of code that would be needed.
Risk assessment is essential in any engineering enterprise. Because no significant technological project can be entirely risk-free, the probabilities for success and failure of particular designs are factored and weighed. The potential for trouble falls into three categories: the foreseen, the unforeseen but foreseeable, and the unforeseeable. In the last case engineers are forced to make decisions with their fingers crossed. The situation facing Heart fell largely into this last category, since so much of the system had no precedent on which to base risk estimates.
The software uncertainties were serious enough, but a plethora of other unknowns existed. For example, how much traffic could such a network handle without encountering logjams? What was the chance that the failure of one node would propagate through the network? In November 1965, for example, one overloaded relay caused a ripple effect that brought down the electric power grid serving the entire northeastern United States. Above all, what was the probability that the network would even work? Signing on for a project like the ARPA network required a certain amount of sheer faith, and that disturbed Heart.
Elkind was motivated by his sense that ARPA was pushing the state of the art of computing into a new era, and from a business point of view, it made a lot of sense to launch BBN toward that future. Elkind recognized that Heart's concerns were rational. “But it struck me that this was a contract we had to do and could do as well as anybody,” Elkind said. “We knew how to work with ARPA and had computer skills as good as anyone around.”
Elkind suggested to Heart that a small group from BBN get together to decide what to do with ARPA's request for proposals. They agreed to meet informally and chose Danny Bobrow's house in Belmont as the location. The first meeting went well into the night. By the time it was over, Heart was converted and BBN's participation had been as much as guaranteed.
That was the easy part. They then had just one month to write a detailed proposal. One of the first people to get involved with the proposal was Bob Kahn, a professor of electrical engineering on leave from MIT and working in BBN's information sciences division. At MIT, Kahn had been an applied mathematician working on communications and information theory. Most of his colleagues possessed a combination of theoretical and applied engineering skills. One day Kahn had been talking with a senior colleague at MIT about the different technical problems in which he was interested, and he asked, “How can you tell when one problem is more interesting than another?” “It's just experience,” Kahn's colleague responded. “How does one get that?” Kahn inquired. “Find someone who has a lot of experience and go work with him.” One obvious place for Kahn to acquire that experience was BBN. So he went.
By coincidence, in 1967, at the time that Larry Roberts was in Washington formulating the network project and its requirements, Kahn was at BBN having his own thoughts about networking. Still more coincidentally, at Jerry Elkind's urging he had been sending unsolicited technical memos to Bob Taylor and Roberts. When Roberts told Kahn that ARPA was planning to fund a nationwide network, it was a pleasant revelation to Kahn. Then Elkind told him that a group in the BBN computer systems division was interested in putting together a proposal for the ARPA network and suggested that Kahn get involved in the process.
Not long afterward, Frank Heart wandered over to Kahn's office. “I understand from Jerry that you've been thinking about the networking area. Can we chat about it?”
“Yes, sure,” Kahn responded. “Who are you?”
In 1968 BBN had more than six hundred employees. Frank Heart's group occupied a row of offices along a stretch of linoleum tiled corridor in Building Number 3. At one end of the hall was a conference room with plenty of chalkboards and seating for large gatherings. The offices themselves were small and unassuming, with desks fashioned from doors to which legs had been attached by BBN's construction shop. Stiff-backed wooden chairs and canvas-backed director's chairs were the preferred styles. Fluorescent lighting, a few personal effects, lots of shelves and little else completed the picture.
Heart liked working with small, tightly knit groups composed of very bright people. He believed that individual productivity and talent varied not by factors of two or three, but by factors of ten or a hundred. Because Heart had a knack for spotting engineers who could make things happen, the groups he had supervised at Lincoln tended to be unusually productive.
One of the first people Heart called upon to help with the IMP proposal was Dave Walden, who had followed Heart from Lincoln to BBN. Though young, with only four or five years of programming experience, Walden had a highly cultivated expertise in real-time systemsâideal for the ARPA network job. Next Heart drafted Bernie Cosell, a young programmer who had been working in BBN's computer systems division. Cosell was a debugger par excellence, someone who could go poking around in a computer program he had never seen before and in two days fix a problem that had gone unsolved for weeks. Heart also enlisted Hawley Rising, a soft-spoken electrical engineer who was an old friend from Heart's student days at MIT.