A new beginning

In the closing years of the 1960s, the Polytechnic of Bucharest — and, in a way, the entire Romanian society — was living in a tension specific to beginnings: a lot of energy invested in modernization, a lot of propaganda around "progress", but also a real (and brief) window of intellectual openness. Between 1965 and 1971, Ceaușescu's regime cultivated an image of autonomy within the socialist camp and of "normalization", including through public gestures with an external echo, such as the condemnation of the invasion of Czechoslovakia in August 1968.

It was a time when the world evolved rapidly from a technological point of view, and the production of computers moved to the industrial phase: solid companies were mass-producing computers for scientific calculations, management, and automation. In Romania, mathematicians and electronics specialists quickly realized that computers would be needed in the economy, and on their initiative, the government adopted, in 1967, a "Program for endowing the national economy with modern computing and data processing automation equipment". The program foresaw the creation of a specialized institute, specialized factories, a service enterprise, an institute to deal with informatization (later known as ICI), a network of territorial computing centers, departmental centers, etc., but also higher education in the field of informatics and computers.

For the university environment, this period meant two simultaneous movements: on the one hand, an accelerated reorganization — new sections, newly created departments, "restructurings" motivated by the emergence of new fields, but also by internal competitions for positions and influence; on the other hand, an increasingly clear pressure for immediate "utility", for linking education to industry and for transforming computing technology into a strategic instrument. It was not just a fad: a state policy of endowing and expanding computing technology was taking shape — not only because it was needed, but also so that Romania would be "among the advanced countries" — and the Polytechnic was to be one of the main nodes of this ambition.

Looking back, I realize that I entered the Department of Computers exactly at the point where modernization still retained an air of enthusiasm, but was already preparing to become rigid. In 1971, the "July Theses" brutally closed this window, pushing back cultural autonomy and strengthening ideological control — including over the university environment.

This did not stop technical development, on the contrary; but it changed its climate: more formal discipline, more obligatory formulas, less intellectual breathing space. In this mixture of momentum and constraint, I actually started my university career.

The "New Premises": the investment, the scale, and the shock effect

When I talk about my first years at the Polytechnic, I cannot separate my beginning from the beginning of another Polytechnic: the "moved" Polytechnic, reconfigured in geography and scale. On July 21, 1969, the first teaching spaces were put into use on the new platform at 313 Splaiul Independenței — the first concrete threshold of what, for my generation, remained for a long time the "New Premises" (Noul Local).

In 1970, things continued at the same pace: new buildings, new classrooms, new laboratories gradually came into operation. I joined the department on March 16, 1970, when courses were still taking place in the buildings in Polizu, Moxa, or 1 Mai, as in my student days, but the new premises were already beginning to impose their logic. It was as if the university was changing, before our eyes, not only its address, but also the way it imagined itself: less "scattered" in historical buildings, more organized as a modern campus, with an infrastructure built for large masses of students and for laboratories that, in the old Polizu, you could not have dreamed of on the same scale.

The architectural project of the "New Premises" is frequently associated with the name of Octav Doicescu, as coordinating architect/chief project manager, who, together with a team of talented architects, created a work of great architectural value, through structural sincerity and environmental integrity. It stands out through consistent finishes (exterior-interior exposed brick). As the rector who pushed the investment and gave it institutional direction, the name of Professor Constantin Dinculescu constantly appears.

Beyond names, the effect of the New Premises was clear: a massive investment, hard to imagine today, which changed the Polytechnic's relationship with the city and with its own ambition. For me, this change of scenery was more than a background: it was a sign that the field of "computers" was not an exotic annex, but a direction that the governing system took very seriously.

A new department at the Polytechnic

On my first day as an assistant in the Department of Computers, March 16, 1970, it was exactly three years since I had been hired at FEA, my former workplace. I considered this period at FEA as a stage in production, useful to my career, but by no means defining for it, proof being that, from the beginning of this stage, in 1967, I enrolled in the courses of the Faculty of Mathematics of the University of Bucharest, which I attended under a "partial attendance exemption" regime, as a second faculty.

The need for adequate premises for the Polytechnic Institute of Bucharest was obvious. When I was a student, because of the steadily growing number of students, many courses, projects and seminars were held outside the “Polizu building”, in various other buildings belonging to the Ministry of Education, more or less suited to this purpose. They were all located in District 1 of Bucharest: on 1 Mai Boulevard (“the 1 Mai building”), on Calea Victoriei (“the Victoriei building”), on Ștefan Furtună Street (“building 303”) and on Mihail Moxa Street (“the Moxa building”). As the university premises in the New Campus were gradually brought into use, IPB progressively abandoned these buildings.

In 1969, when I was already a third-year student in Mathematics, I had taken an exam at the Department of Automatics headed by Professor Corneliu Penescu, but, although admitted, the professor knew me, it was not to be that I reached Penescu's department. I had the chance that the teaching staff restructurings necessary for the establishment, in 1969, of the new Department of Computers changed my destination as an assistant towards the latter.

The new department was formed by feeding teaching staff from departments of the recently established Faculty of Automatics, and from departments of the Faculty of Electronics, where the two "coryphaei" of the new department also came from: its head, Mircea Petrescu, as well as its future head, Adrian Petrescu, my former professors from the Electronics course and, respectively, the Electronic Computers course.

This type of change in the organization of the Polytechnic was primarily due to the emergence of new fields or specializations, but also to the political militancy of some teaching staff who had to find a leadership position. Such restructurings were done by borrowing teaching staff and students from various existing specializations or departments. They characterized the 1960s at the Polytechnic.

This is how the repeated splits of departments at the Faculty of Electronics were carried out, this is how the section of physicist engineers was also formed at Electronics. In 1962, Professor Corneliu Penescu managed to establish a Department of Automatics, the first in the Polytechnic Institute, and to create an Automatics section within the Faculty of Energetics.

Several graduates from the Faculties of Electronics, Electrotechnics, and Energetics from that year were recruited into this department, and in the new section, the students in their first years with the highest grades from the same faculties. Among these students, I was also chosen.

The procedure was beneficial when it came to students in their first years of study, but less beneficial when it came to teaching staff with already formed personalities and divergent interests. This is also the case with the formation of the Department of Computers from teaching staff coming from Electronics and Automatics, dissidents, in most cases, of authoritarian regimes in which they felt they had no possibility to assert themselves.

The two distinct origins were never forgotten by those "restructured", leading to the formation of two factions, if not rival, at least in competition for affirmation within the department. The factions remained distinct for years, feeding with new members from the successive generations of graduates of the Computers direction, recently established in the Faculty of Automatics.

Throughout the 1970s and 1980s, the two heads of department, themselves engaged in the existing factions, failed to standardize the entire collective around major research topics, the possible standardization being only at the superstructural level, the one formed by collegiality and friendships created between the members of the two factions. The situation became complicated when, after 1972, two distinct research directions emerged in the field of computers: hardware and software, a phenomenon that led to the emergence of a third faction, that of software, in the competition within the department. The situation perpetuated even after the withdrawal or disappearance of the founding members.

The first day as a teaching staff member at the Polytechnic

On my first day of work, I presented myself at the department's headquarters in building F, 2nd floor, room F202, of the Polizu premises. I expected to find an animated atmosphere, but the room was empty. Puzzled, I went to the department's secretariat in building A, where I found out the reason: most of my colleagues had left for specializations abroad, benefiting from scholarships in Western countries.

That is how I found out about a UNDP-UNESCO program destined for our department, initiated by a recently established UN agency. The program aimed to improve the teaching staff through specialization stages (scholarships) abroad for all members of the department. In addition, it offered us the possibility to receive renowned professors in Bucharest, to familiarize us with the latest concepts in the field, as well as access to specialized books and magazines from abroad for the department's library. Another important provision was the acquisition of a Hewlett-Packard minicomputer, a state-of-the-art equipment at that time.

After a period of 20 years of total closure of Romanian research's access to scientific resources in the West, this program was not just a privilege for the teaching staff, but a true paradigm shift. The intensive specialization of the professors and the exposure to the newest theories transformed the department into a center of excellence, one of the few in Romania in those years, when access to technology and specialized literature was severely limited. Through us, entire generations of students benefited from this opening to the world.

The transfer to the New Premises

While waiting for the return of my colleagues who had left for specialization, I was entrusted with the teaching task of assisting Adrian Petrescu at the Electronic Computers course at the Faculty of Electronics, dealing with the laboratory classes. I immediately loved this activity, especially thanks to the students — enthusiastic and eager to learn. The relationship with the titular professor of the course was also excellent. Among the students of that year were a few future fellow colleagues, who would become teaching staff or researchers: Irina Athanasiu, Lucia Coculescu, and Adrian Mihalache.

My classes with the students took place in the old buildings of the Polytechnic, especially since the Faculty of Electronics was the last to leave the Polizu headquarters to transfer to Cotroceni, but not in the New Premises like all the other faculties, but in its own building, the aspiration towards autonomy being specific to this faculty.

When, in the following years, I started teaching at other faculties in the Polytechnic: Aerospace and (Fine) Mechanics, the center of gravity of my activity shifted to the New Premises.

Here, the problem of space no longer existed: the Department of Computers received space in the building of the Polytechnic's Computing Center, Professor Mircea Petrescu being the head of both units. This symbiosis was maintained for over 20 years, until the Computing Center was abolished.

The EF building of the Department of Computers and the Computing Center was (and still is today) an edifice composed of two segments, one of which, the one looking towards the Rectorate's "mushroom", and seen from the valley looks like a tower on the crest of the hill that guards the Polytechnic campus, a campus that stretched to the Dâmbovița river and even beyond it, where the dormitories were, some newer, others from my student days.

On the ground floor of the "tower" were the room of the FELIX C-256 computer, the dispatcher's office, and the punch card rooms, which served users from all over the Polytechnic who came to run and correct their programs. On the first floor were the computers received from the University of Darmstadt: an IBM 1401 (practically unused), an almost new IBM 1130, but already considered outdated back home, and an HP 2116 B minicomputer, fashionable at the time, obtained with the UNDP-UNESCO program. On the second floor were the meeting room, the offices of the head of the Computing Center and the secretary, as well as the library. The third floor was occupied by the laboratories of the Computing Center's technicians.

The other segment contained offices, mostly occupied by the department's staff. The ground floor was dedicated to card punchers, some used by the Computing Center's operators, others for users from the Polytechnic — students and teaching staff. The other three floors were occupied by the teaching staff's offices. A real luxury in the early years! Then, as new teaching staff and new needs for laboratories appeared, the initial space became insufficient and a few rooms adjacent to the Center, but belonging to the Departments of Automatics, were obtained and allocated to the Department of Computers.

My office was on the second floor, room EF 203. The office, extremely bright due to an entire wall of windows, contained two work desks, a few chairs, a chalkboard, and a built-in closet up to the ceiling, which I quickly filled with student papers and projects, books, and xerox copies of articles.

The view from my office's wide window went far into the distance, towards the Rectorate and, beyond, towards the Grozăvești thermal power plant. But, closer, over the Polytechnic's fence, I could see the courtyard of a ferrous metal foundry, for a production of iron machinery, a unit that used to cast bombs in the past. The foundry was supplied by a railway that crossed the space allocated to the Polytechnic and the nearby residential neighborhood, parallel to Armata Poporului Boulevard. Rarely, a locomotive with a few wagons would lazily pass on this railway. After the Revolution, both the foundry and the railway disappeared, remnants of other times, when the Cotroceni hill was occupied only by military units and their maneuvers.

From the very beginning, I shared the office in the New Premises with Petre Dimo, an assistant during my student days, who over time became a friend and mentor. Petre wrote a book on programming in FORTRAN IV in 1970, with which he became known throughout the country as a leading exponent of domestic software. His attraction to computer programming also contaminated me, especially since at that time I was finishing my studies in the Computing Machines specialization at the Faculty of Mathematics of the University of Bucharest, with a predominant focus on programming languages. With Petre, I also wrote my first research article for the Cybernetics Congress in Bucharest in 1973. It was about the role of short-term memory in human activities. Until Petre's departure from the Polytechnic, we worked together on the same courses, I first as Petre's assistant, then also as titular of the same course taught to parallel series.

Admission to the PhD program

The doctoral system in those years was regulated by laws from 1967. According to them, doctoral studies were led by professors approved by the Ministry of Education.

Adrian Petrescu received the right to supervise doctorates in 1972. At that time, he was also the interim head of the department, because Mircea Petrescu was on a long-term internship abroad. On the very evening he received the news, Adrian Petrescu called me and told me to report to the Rectorate the next day to enroll in a PhD under his supervision. I refused him.

When he heard my refusal, he was shocked and, after a few moments of silence, he angrily reproached me, in his characteristic style that did not take consequences into account:

"I was your professor, I am the titular of your course at the Faculty of Electronics..."

I explained to him that, before Mircea Petrescu left, anticipating the imminent PhD admission session, I had asked him to accept me as a PhD student.

"Mircea Petrescu agreed, and I cannot take my word back now," I told Adrian.

Admitted to the PhD admission colloquium in the absence of Mircea Petrescu, I was to discover that, once returned to the country, he had forgotten his promise and had another candidate in mind. His dissatisfaction affected my academic path more than I would have imagined; my relationship with him remained tense for over 25 years.

To this was added the fact that it took him almost a year to be able to write his approval report for the defense of the thesis, when after 6 years I managed to make a thesis that satisfied me. Only then, in 1992, at a considerable distance in time, did I become one of his favorite interlocutors. As for my relationship with Adrian Petrescu, it was permanently compromised.

The transition years – between teaching, research, and the PhD

In the first three years after admission, the thesis remained in the background. My time was absorbed by teaching activity, by teaching two new courses, by a thorough deepening of the subject, and by developing a fundamental understanding of the field of informatics.

In parallel, I dealt with problems related to compilers, such as program portability, the design of macroprocessors of various types, and even a compiler for a real-time language, developed under a contract with ICI.

I dedicated a significant part of my time to collaborating with students – from writing articles to implementing their themes for diploma projects, which I often chose in order to clarify theoretical aspects of the two courses for myself. Many of my parallel researches would find their place, in one form or another, in my doctoral thesis.

Thus, the initial plans were diverted, and the completion of the thesis was postponed. All this pushed the deadline for completing the thesis beyond the initial plans: in the end, it took me seven years to defend the thesis. This was not just a delay, but a natural process of scientific maturation: new research directions appeared, some more challenging and tempting than others, which inevitably attracted me and contributed to this delay.

As often happens in research, the path of a doctoral thesis is not always linear, and the initial objectives change: they evolve as new perspectives and opportunities for exploration emerge. In the end, my work was not just an academic formality, but an authentic reflection of my journey in research — with constant questions, adjustments, and rediscoveries.

The first courses as a titular professor

During the period when I was admitted to the PhD, I was working in the team led by Petre Dimo on a conversational parser for students, to help them edit and debug their FORTRAN programs.

Although the objective of this parser and that of my ALGOL60 compiler were similar – to facilitate human-computer interaction – the two parsers were fundamentally different. ALGOL60 had a formal syntactic definition and a narrative semantics, which allowed a rigorous approach in designing the parser. Instead, FORTRAN did not benefit from such formalization, so its parser had to be designed artisanally, relying exclusively on a narrative description of the language.

By coincidence, following the UNDP project, which exposed us to what was happening in the major universities of the world, a new curriculum was adopted at the faculty in 1973. This was revolutionary compared to the previous one and introduced, among other things, two essential courses: Automata Theory and Formal Language Theory, taught in sequence in the penultimate year of studies. I was designated to teach them, being also a graduate of the Faculty of Mathematics. Fortunately, I was not a novice in the matter – my last year of studies in Mathematics and my bachelor's thesis had given me the opportunity to familiarize myself with these two theories.

However, even if I wasn't starting from scratch, writing the courses required considerable effort. I aimed to give them a conceptual coherence and achieved this by introducing the concept of a formal system, a unifying framework that covered both automata and formal languages.

For the first course, Automata Theory, I expanded the classic presentation by introducing two essential chapters for a computer scientist's culture: computability with the Turing Machine and the theory of recursive functions.

The second course, Formal Language Theory, allowed me to broaden the area of study and introduce the formal system as a logico-mathematical object, an axiomatic framework in which propositions are derived from hypotheses through inference rules. Rewriting systems were a particular case of formal systems, and formal languages a particular case of rewriting systems. Finally, the Chomsky hierarchy of grammars offered me an elegant way to map formal languages to the automata taught in the previous course.

As I wrote, my mother typed the pages for me on the typewriter so I would have them ready to be duplicated and distributed as course notes. Surprisingly, although they were dense, full of mathematical formulas and proofs, the courses were successful.

Not immediately – at first, the students encountered difficulties – but, later, many told me that these courses were of great help to them in their careers. And for a professor, this is the greatest satisfaction.

The truth is that these courses not only shaped generations of students, but they also forged for me a way of approaching and understanding reality that proved highly successful over time, profoundly influencing my research. In my future research fields: software engineering and systems engineering, the use of mathematical models from the two courses was invaluable. My software engineering research book published by Prentice Hall in 1992 extensively uses the models from Automata Theory and Formal Language Theory.

I have no doubt about the necessity of these courses in the training of a computer science specialist or in Artificial Intelligence, whether mathematician or engineer. At a time when the place of many traditional courses is being re-evaluated in new curricula, I believe these two disciplines should be considered fundamental courses for the training of a computer engineer, just like mathematics or physics.

But one aspect is essential in the decision to introduce them: they must be taught well. It is not at all simple. It requires total dedication from the professor to understand the subject in depth and transmit it clearly. Otherwise, they become counterproductive, risking to create rejection instead of passion.

During these years, my teaching activity was not limited to the relationship with the students. I also collaborated closely with my colleagues, creating a software-oriented group – a third faction within the department – which contributed significantly to the development and implementation of innovative projects in the software field.

A small "bridge" from assistant → to lecturer

Naturally, my beginning as an assistant was a combination of apprenticeship and improvisation: laboratories to teach, materials to prepare, courses to follow from the inside, colleagues to understand, alliances and prides to decipher. Then, as the department stabilized and directions differentiated, my role changed: I went from "supporting" to "building" — courses, assignments, lecture notes, projects with students, my own area of interest.

At that point, the transition to lecturer (șef de lucrări) in 1975 was not just an administrative promotion, but the recognition of a simple fact: I was no longer a person "on probation", but one who was beginning to give shape to a part of the school that was being born then.