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Grace Murray Hopper, born on December 9, 1906, was a groundbreaking figure often referred to as the “grandmother of computer programming”. She earned a Bachelor’s degree in math and physics from Vassar College in 1928, and later a Master’s and a PhD in mathematics from Yale. After her studies, she returned to Vassar as a full-time professor for ten years before World War II began.
Early contributions and the birth of “debugging”
In 1943, driven by a desire to contribute to the war effort, Hopper joined the Women Accepted for Volunteer Emergency Service (WAVES) program, which expanded women’s roles beyond nursing and administration. She was assigned to work on the Mark series of computers at Harvard.
Hopper proudly reminded her audiences that the first large-scale digital computer in the United States was a Navy computer, operated by Navy crew during World War II, a fact she often had to reiterate due to claims from other services. She herself was the third programmer of this first large-scale digital computer in the U.S..
While working on the Mark II computer during the hot Cambridge summer of 1945, she encountered an unusual glitch. The computer inexplicably shorted out due to a moth stuck in a relay. The operator carefully removed the moth, taped it into the log book, and wrote “First actual bug found,” a moment that cemented the term “debugging” in computing. This original “bug” is still preserved in the museum at the Naval Surface Weapon Center in Dahlgren, Virginia. Hopper often noted that the Navy kept some of these early artifacts, including herself.
Revolutionizing programming with the compiler
In 1952, Grace Hopper and her team made a revolutionary breakthrough: they invented the first compiler. This program translated common-sense commands into binary computer language, fundamentally transforming computer programming. Her work laid the foundation for every subsequent programming language, making it “no exaggeration to say that we owe computer programming as we know it to Hopper”.
A career of unwavering service and innovation
Hopper officially retired from the Navy in 1966 at age 60, having completed 23 years in the reserves. However, her retirement was short-lived. Less than a year later, she was recalled to active duty by the Pentagon to undertake the crucial task of standardizing high-level languages, particularly COBOL, across the Navy.
She recounted that her new team began this task without a budget, computers, or even basic office supplies. Despite these challenges, they operated resourcefully, famously adopting the motto: “If it isn’t bolted down, bring it home”. They relied on “slack time” on Pentagon computers for their programming needs, demonstrating portability by writing programs that could run on “anybody’s computer”.
Hopper’s efforts led to the successful development of test routines for COBOL and FORTRAN compilers, ensuring adherence to American National Institute standards. This work eventually led to the Navy establishing a compiler testing service for the entire Department of Defense and later the federal government. She expressed immense pride in the achievements of the young people who spearheaded these developments, with several receiving Navy achievement awards.
Key insights and forward-thinking principles
Grace Hopper’s lectures were filled with profound insights and forward-looking principles that extended beyond technical specifics.
- The Model T of Computing: Hopper believed that the computer industry in her time (1982) was at the beginning of its “Model T” phase, similar to the automotive industry’s transformation under Henry Ford. She cautioned against repeating past mistakes, such as focusing on individual components (like automobiles or hardware) while neglecting the overall system (transportation or information flow).
- Prioritizing Data and Information Flow: She stressed the critical importance of looking at the “total flow of information” within an organization before selecting computer systems. Hopper lamented that for thirty years, the focus had been on processing, hardware, and software, neglecting the raw material: data, and the output product: information. She firmly believed that hardware and software are merely tools, and the primary focus should be on data and information.
- The Value and Cost of Information: Hopper highlighted the shocking lack of research on the value of information. She argued that current priority assignment in computer systems often goes to the “senior squeaky wheel” rather than the most valuable information. She used a compelling example of a chemical plant, contrasting the value of a valve alert (plant explosion, 100 lives at stake) with an overtime report (Joe did 2 hours of overtime) to illustrate this point. She proposed criteria for valuing information: time to act, number of lives affected, number of dollars affected, and its importance in decision-making.
- She also extensively discussed the possible costs of incorrect information. Citing Lieutenant Colonel Randleman’s study, she pointed out that due to privacy laws, individuals denied promotions or raises because of incorrect personnel file information have the right to sue the federal government. A hypothetical scenario with 8,000 personnel files, even 95% correct, could lead to a potential loss of nearly half a million dollars in lawsuits from negative decisions based on incorrect data. This underscored the need to compute the economic cost of incorrect information to justify spending on data correction.
- Understanding Time in Computing: The Nanosecond: To help people grasp the incredibly fast speeds of computers, Hopper would famously demonstrate the nanosecond. A nanosecond, a billionth of a second, is physically represented by a piece of wire 11.8 inches long, which is the maximum distance electricity can travel in that time. She also showed a microsecond (a millionth of a second) as 984 feet of wire, suggesting it be hung over programmers’ desks to remind them what they “throw away”. This practical demonstration helped explain why equipment needs to be close together and why satellite messages take time.
- The Future: Systems of Computers: Hopper foresaw the need for “systems of computers” rather than relying on increasingly large single machines. She used the analogy of farmers using two oxen to move a heavy log instead of trying to grow a bigger single ox. This approach, she argued, aligns with common sense and is becoming economically feasible with inexpensive microcomputers. She envisioned three-dimensional flowcharts and physical models using chemistry sets to design these complex systems. Hopper cited the Massively Parallel Processor being built by Goodyear Aerospace for NASA, containing 16,384 processors in one system, as an example of this future. These systems would allow for parallel processing instead of sequential, offering better security and lower costs. She also emphasized the importance of specialized machines for specific tasks, such as database management machines (first proposed by Bell Labs in 1972 but slow to be adopted) and dedicated weather or ocean machines.
- Software Design: Independent Modules: Hopper advocated for writing software in independent modules with single entry and exit points, and no module accessing the interior of another. Data exchange would occur through well-defined interfaces. She cited Dr. Haney’s mathematical proof, which demonstrated that this modular approach could prevent cascading changes that make large systems unstable and difficult to maintain. Her crew successfully built a COBOL compiler using this technique, showcasing its efficiency and benefits for documentation and maintenance.
- Challenging the Status Quo: “But We’ve Always Done It That Way”: Hopper fiercely opposed the phrase “but we’ve always done it that way,” calling it the “most dangerous phrase you can use in a computer installation”. She kept a counter-clockwise clock in her office to emphasize that conventions can be questioned and changed. She even humorously “haunted” those who uttered the phrase for 24 hours to encourage new thinking.
- Listening to Young People and Embracing Leadership: A core theme in Hopper’s philosophy was the absolute necessity of listening to young people. She believed they possessed immense knowledge and an eagerness to learn, often far exceeding what older generations knew at the same age. She shared examples of young Navy personnel who innovated by bringing their own microcomputers aboard ships to manage records or maintenance, without seeking permission, embodying her famous advice: “It’s much easier to apologize than it is to get permission”. This entrepreneurial spirit led to initiatives like Navy microcomputer seminars and the “Chips Ahoy” magazine, all driven by young enlisted men.
- Hopper also emphasized the crucial role of “positive leadership,” defining it as a “two-way street” of loyalty up and loyalty down, where superiors inform and take care of their crew. She distinguished between managing things and leading people, a lesson she often attributed to the Marines. She believed this kind of leadership was what young people were truly seeking.
- The “Cost of Not Doing Something”: Hopper consistently urged people to consider the “cost of not carrying out the plan” or “cost of not doing something”. She cited a General Accounting Office (GAO) study that revealed a staggering $450 million per year was lost due to the federal government’s failure to implement standard high-level languages, a clear example of the tremendous cost incurred by delaying necessary changes.
Legacy
Grace Hopper passed away on January 1, 1992. When asked about her greatest accomplishment, she was known to respond simply: “All of the young people”. For herself, she stated that the highest award she ever received was the “privilege and the responsibility of serving very proudly in the United States Navy”. Her career and teachings continue to inspire generations of computer scientists and leaders.