The class that never really ended

According to those who know him, David Pheanis is an emeritus professor who seemed to delight in teaching one of Arizona State University’s hardest classes.

Despite their difficulty, his courses inspired fierce competition for top rankings and coveted internships. His quizzes often arrived without warning, and his homework assignments pushed students to the edge of what they thought they could do.

But his classroom also produced lifelong friendships, one marriage, an annual reunion and a network of engineers who still credit their careers to the professor who made them sweat.

Every year, decades after graduation, former students gather to celebrate the computer scientist. Some drive across the Valley, while others fly in from out of state. They trade engineering stories, solve one of Pheanis’ trademark brain teasers and, inevitably, talk about the class that terrified them.

Next year, they’ll celebrate Pheanis’ 80th birthday.

But being computer engineers, they refuse to call it his 80th. To them, it’s his 50th because, in hexadecimal — the number system they learned to love in Pheanis’ classroom — 0x50 = 80.

That joke captures Pheanis perfectly: equal parts technical precision and dry humor.

Pheanis never set out to become the professor generations of engineers would remember. After earning a mathematics degree from Case Western Reserve University in 1969, he joined the U.S. Air Force expecting to use his mathematical training. Instead, an officer asked him what practical skills he had to offer.

“I told them I could write programs in this language called assembly,” Pheanis says. “And then they were interested.”

The Air Force assigned him to computer programming, launching a career that eventually led him to ASU, where he earned master’s and doctoral degrees before becoming one of the founding faculty members of the university’s computer science program.

From 1975 to 2004, Pheanis taught microprocessor systems, helping build the foundation of what is now the School of Computing and Augmented Intelligence, part of the Ira A. Fulton Schools of Engineering at ASU, while simultaneously consulting with companies, including General Motors, Motorola and Inter-Tel.

“I knew right away that I enjoyed teaching,” Pheanis says. “There is something very rewarding about giving someone a challenge and helping them figure out how to solve it.”

His courses focused on assembly, the programming language closest to the hardware itself. Pheanis believed engineers who understood what was happening under the hood could write better software no matter what language they used later in their careers. Programming in assembly was painstaking work that required students to think about every instruction, every byte of memory and every line of documentation. That rigor became the foundation of hundreds of engineering careers.

Pheanis’ students describe his challenging classes with a mixture of affection and disbelief.

“His class was definitely the hardest I’ve ever taken,” says Chris Budd, ’94 BSE in computer systems engineering. “I spent a lot of time that semester in his office hours, so that’s where we really started to get to know each other, and I’d say a friendship formed. So, I’m still friends with him today.”

Pheanis didn’t teach from a textbook. He built his own assignments from engineering problems he encountered while consulting. Students optimized code until it was as fast and memory efficient as possible, competed to beat Pheanis’ own benchmark solutions, and then defended every line of documentation with proper grammar and active voice. In the 1990s, ASU Insight described his classes as “killer courses” that prepared students for demanding workplaces, noting that Pheanis spent summers solving industry problems and transformed those experiences into classroom assignments.

Pheanis had a parallel role as founder of the consulting firm Western Microsystems, solving real-world engineering problems for Arizona companies while bringing those challenges back into his classroom. When Inter-Tel, a Chandler-based telecommunications company, recruited him to help modernize its software in the early 1980s, Pheanis had never worked in that industry. But his response was, “How hard can this be?”

At Inter-Tel, he quickly learned the telecommunications industry and helped improve the company’s early microcomputer systems. That experience gave him a direct view into what employers needed.

Pheanis went on to help build one of Arizona’s most influential engineering talent pipelines.

Over the course of his career, Pheanis personally connected more than 300 students with internships, many of which turned into full-time jobs. Those students went on to help build Arizona’s technology industry.

Tom Peiffer, a former Inter-Tel engineering manager who worked alongside Pheanis during the professor’s years as an engineering consultant to the telecommunications company, watched it happen from the employer’s side.

“David Pheanis was the right person at the right time to get a lot of the early microcomputer systems efforts in the Valley started,” Peiffer says. “He knew what was going on inside the minds of his students, and he could spot the talent.”

His recommendations became so trusted that hiring managers often stopped interviewing candidates until Pheanis approved them.

Joe Taylor, ’95 BSE in computer systems engineering, eventually found himself doing the same thing.

“Anybody who’s a fan of Dr. Pheanis, I don’t need to interview,” Taylor says. “I need to recruit them.”

For students, the influence extended well beyond careers.

Brady Barnes, ’81 BSE in electrical engineering, remembers Pheanis patiently teaching him about investing and rental properties. Ryan Jones, ’02 BS and ’04 MS in computer science, says Pheanis helped him find not just one job, but two, while also shaping the way he mentors younger engineers today. And Jeff Tenney, ’99 BSE in computer systems engineering, met his wife, Susan,’99 BSE in computer systems engineering, because she was determined to discover the anonymous student who kept finishing first in Pheanis’ class rankings.

“Dr. Pheanis first cared about learning my name,” Jones says. “And then wanting me to rise to what he was challenging me to do.”

That combination of relentless standards and genuine care created extraordinary loyalty.

In 2003, Sethuraman Panchanathan, then chair of ASU’s Department of Computer Science and Engineering and now University Professor of Technology and Innovation, found himself facing an unusual problem. As part of a broader curriculum reorganization, the department planned to move Pheanis out of his signature microprocessor systems course and into another engineering class. Sixty students showed up outside Panchanathan’s office to argue that Pheanis belonged where generations of engineers had learned from him. More than 140 students ultimately signed a petition asking the department to allow him to continue teaching his signature course. After meeting with students and faculty, leadership reversed the decision.

“I’ve been around universities for a long time, and I don’t know many professors whose students complain all semester about how hard the class is and then organize to make sure no one ever takes it away from them,” Panchanathan says.

Pheanis remains characteristically modest about his impact.

“The best students are those who are responsive to both challenges and opportunities,” he says. “These students would have been successful without me, but I like to think I played a role in helping them get where they needed to go.”

His former students disagree.

They’ll tell you he launched careers, built companies and taught them to think more carefully than anyone else ever had.

They’ll also tell you one of his favorite jokes.

“What does the agnostic, dyslexic insomniac do?” Budd still remembers Pheanis asking from the front of the classroom.

“He stays awake at night wondering if there really is a dog.”

Today, more than 20 years after Pheanis’ retirement, the students who once nervously awaited his surprise quizzes are organizing his next birthday celebration. The guest list grows every year as former students reconnect with classmates they first met while trying to squeeze one more byte out of an assembly-language assignment.