/ #Junction #Interview 

Junction: A chat with dr. ir. Sabih Gerez

We interviewed Sabih Gerez, assistant professor of the Computer Architecture of Embedded System (CAES) group. While bachelor students may not be acquainted with him, he is well known under a large portion of the master students Electrical Engineering. All the students who followed the mandatory course System-on-Chip Design have met this busy man. Besides teaching one day (on paper) at the University, Sabih also runs his own company. During this interview we asked him all about combining industry with education.

As not many bachelor students are acquainted with Sabih, we asked him to introduce himself and explain his role at the University.

Well my name is Sabih Gerez, you know that already. I am a part-time assistant professor. I only work eight hours a week on paper, in practice maybe twice. At this time I do both a bit of research and education, actually quite a lot of education for a person that only works one day a week. I’m busy with the System-on-Chip course, from September to January, because it is a 10 EC course, there is also a 5 EC variant. From February till April I give the Implementation of Digital Signal Processing (IDSP) course and during the fourth quartile I’m free of regular education. Then I’m busy with the examination of the IDSP course and the preparation of the System-on-Chip course. At the same time I’m supervising a PhD student and I’m trying to supervise two master students who are under my direct supervision and I’m in the committees of other students. I’m in the CAES group and my interest is mainly in digital hardware and chip design. My work outside the University is a one-person company consultant and I’m helping other companies whenever they are in need of extra capacity. That’s all about chip design, I work on digital design and verification. I try to bring experience that I see in the industry into the University and sometimes things I see at the University come quite of use when I’m doing practical work.

So you mentioned that you have your own company, could you tell us a bit more about that?

In principle it is meant to put my skills to anybody that needs them. Let’s go back to about twenty years ago. Until January 1st 2001 I was a full time assistant professor at the University of Twente, but then I decided that I was very curious about what was happening in the industry. So luckily I could make an agreement with the University of Twente and a company that I could work one day at the University and four days a week at the company. Later I became independent and started my own company. During those years, I really gained a lot of experience at the industry level of design. At the University we are satisfied when things more or less work, but in practice it’s different. For example when we talk about VHDL, when you modify one line of VHDL this may affect the complete chip and you might have to go back to hours of simulation. That way of thinking is something you learn in the industry. At the University we do not consider changing one line of code as a big change, and as something that changes the complete code.

How do you balance between your company and teaching?

Yeah… that is difficult. In the end it means that I’m doing a lot of overworking. The company work is often paid by hour, so I agree to a number of hours and I try to stick to that. I consider my work for the University as a kind of hobby. Otherwise it would not be justifiable. I put in extra time, but I enjoy it. I enjoy the contact with students and developing educational material. Because my courses are practically oriented, I develop exercises. I like the exercises to be solid and robust, that when I give code to the students that the code doesn’t crash. I put in a lot of effort to make sure that things work and are of good quality. This costs a lot of time, I keep track of the hours by the way. In theory the time that I put into my University work and commercial work should have a ratio of 1 to 4, but in reality it is closer to 1 to 3 or even 1 to 2. So the answer to the question is that I do not really manage to balance it, it is unbalanced.

So what really pushes you to teach next to your job?

I’m not sure whether I’m such a good teacher, I see other teachers who are more comfortable making jokes for example. I like to explain things. People in my private environment sometimes complain that I’m always explaining things, even when things are obvious. That’s my nature. I always supported my kids, when they were in school, even when they did not want to.

And do you have other hobbies besides teaching?

Well teaching is my hobby more or less. I try to keep a bit in shape by going to the fitness center or jogging outside. I read a lot of newspapers. My iPad is my companion, I have subscriptions to several newspapers and magazines. I like to play bridge online. Since I was a child I have liked to play bridge. During my student time I was a member of the Bridge Club Drienerlo, that doesn’t exist anymore. Nowadays I don’t play bridge in clubs anymore, only online. After I finish work and I want to relax a bit, I like to play half an hour of so.

How did you end up in your teacher role?

I studied Electrical Engineering for five years here at the University. Back then there was no separate bachelor and master program, it was a five year program. After that I did my PhD, I was already asked to be a teaching assistant to help during tutorial sessions. And then, when I became a full-time assistant professor in 1990, one of the conditions was that I should develop a new course. Those were the days that microelectronics were booming, my PhD project was funded because there was a necessity to not only to design but also develop design tools. That is actually my background, my background is much more into tooling than into design. After I went to industry in 2001 I became more a designer and left behind the tool development. My PhD was about tooling and especially about wiring patterns to interconnect blocks on a chip. So I had to develop a new course about computer aided design tools for chip design. That’s how I started. Of course I was also involved in bachelor courses, such as circuit analysis. But I developed my own course from scratch and it was about computer algorithms that I used in design tools, such as simulation algorithms, placement and routing, logic optimization, high level synthesis, covering all that. Those days I started with papers, for each topic I found tutorial papers. But gradually I started to write connecting texts between the different papers, I started to eliminate the papers and add more text of myself and in the end (after five/six years) I had my own book. I managed, after quite some ups and downs, to find a publisher who was prepared to publish it, so the book I have on design automation is the result of one of the conditions when I started working at the University. It was not an extremely popular course, in the beginning it was, I had 20 students. It gradually became less and less, but in the meantime the book was ready. Then the book started to get sold all over the world, it is popular in India and China. I still enjoy the fact that the book is still being used, although it is from 1998. It also gives me satisfaction. A while ago I received an email from someone from Kuwait saying that he’s going to use my book and asking whether he can use my slides. After so many years people are still interested in using the book.

How were you as a student?

I was very ambitious. I came to the University of Twente in 1979 and I registered for Electrical Engineering, but my interest was more into Computer Science. But Computer Science did not exist yet as a standalone study. If you wanted to work in Computer Science, you had to register as a student in Electrical Engineering or mathematics. I decided that Electrical Engineering was wider, so I joined that study. As soon as we started to have elective courses, I chose all my courses in the field of Computer Science. I was a good student, I never doubled any examination and in the end I graduated with honours. I was so ambitious that when I was not certain about being strong enough at a certain topic, I wouldn’t go to the examination. I ended up doing a lot of Computer Science courses, because in 1980, just one year after I started studying, you could study Computer Science. And by coincidence, I went to a professor of Computer Science and said to him that I wanted a master graduation project and talked to one of the members of his group who had very close connections to Electrical Engineering. He said, we can make a joint master program. He was working on formula manipulation, computer algebra it is called now. He suggested that, instead of manipulating algebra, we can manipulate boolean expressions and we can apply that to chip design. And that’s how I entered the field of chip design. I started to look at common expressions for boolean expressions, and then into automatic lay-out generation and the rest is history…

So I was an ambitious student, I did not want to waste my time with things outside my study. I have more or less done the program at nominal speed. Which was quite exceptional at that time. When I graduated I looked around and I did not know most of the people, because they started 3 or 4 years before me. I was also interested in mathematics, I was writing for the Vonk. I was running a column about recreational mathematics.

When talking to other Electrical Engineering teachers, they mentioned that they enjoyed electronics from high school. Was that also the case for you?

Yes, it was. I was born in Istanbul; not in The Netherlands. My father is also an Electrical Engineer who studied at the Technical University of Istanbul a very long time ago. The time he graduated in 1948, was around the same time when the transistor was invented (he is still alive by the way, almost 98 years old). My father used to stimulate me a lot to enter the field of his own. So when I was six years old I already had an experiment box, this was very rare in Istanbul. However since my father knew someone who was making those things, he managed to get one. The box came with a board, 3 transistors, a loudspeaker, a number of capacitors and resistors. In those days, I wouldn’t understand anything, fortunately, there was a book that showed where you had to connect the resistors with the transistors and so on. There was also a coil that you could tune and get a radio to listen to.

When we came to The Netherlands when I was 11 years old, I brought this experiment box with me, which also played a part in the friendship between me and my very close childhood neighbour friend. He was a boy almost the same age as me. We developed a little bit of an electronics hobby. In Secondary school, around the age of 13-14 years, first we built an intercom between our houses. Since we were neighbours, we connected a wire coming out from his window into mine; we would then talk to each other with an intercom. In those days, we had something called De Jonge Onderzoekers (young researchers – Ed.), it was some kind of a hobby club, that published a monthly magazine where you could search for some experiments to conduct. These people used to also sell chemicals to etch PCBs. So we were then also making primitive PCBs. Especially my friend, my neighbour, he was much more fanatic than I was.

At a certain moment when I was 15-16 years old, I developed an interest in digital electronics. That was the time when you had the 7400 series of Texas Instruments, you had one IC with 4 NAND gates in there or you had one IC with 2 flip-flops and you could make little circuits. I enjoyed it a lot, especially digital electronics.

I really got interested in digital electronics immediately; I fondly remember it wasn’t with very sophisticated things but once I visited an exposition and people were distributing some leftover materials like a telephone dial, the ones that you dial and they generate pulses say 10 pulses for dialing 0, 2 pulses for 2. I connected that to my digital electronics and I could for example show on a 7 segment display how many pulses this dial was generating;. And if you dial twice it would show some additions. Those were the kind of things I did in my secondary school.

What is the biggest change in the University comparing your time at the University and now?

I think the complete way of teaching, especially the technical part has changed. I remember when I had to teach without things like PowerPoint, where we would have to make the slides, go copy them onto transparent sheets and project them, further on since students would like to have copies, we would also have to go make copies of them and further distribute them; so all in all it was much more time intensive. In that sense things have become easier. There is also so much material that is easily available on the internet; if you’re looking for extra material, you just have to open Wikipedia. I remember as a first year student in the very first trimester (we used to have trimesters in those days), we had a thermodynamics course, it was pure physics, quite tough physics. I didn’t really understand all the concepts of thermodynamics, but I really wanted to understand it. So I would have to go to the library and physically look for books and take them out. There were literally so many books, but I would look for the one that would help me the most in understanding the theory presented in the lecture. I used to spend a lot of time in this way, in these kinds of things, just to collect information, also in research, much more than in education. I still remember the efforts I had to make to get a paper, especially if the journal was not part of the University of Twente subscription; you would then have to apply externally to find out, and maybe this Journal was part of Delft or a university in Germany, then you would have to wait for three weeks to get the three pages. Fortunately, now it is much easier, it is just a click away. We used to search for articles with the help of related research through some combination of keywords in some really huge books in the library; every year the librarians would have to renew these kinds of books, and throw away the old ones and get new ones. It was a lot more effort to get your information, things are much easier to access now and that is the main change.

How would you describe the perfect student?

The perfect student, haha. Well, in my view, the perfect student is dedicated to what he or she wants to learn. Ideally the student for example prepares the lecture in advance; so if you know a certain topic is going to be presented in the lecture, you would already read the corresponding chapter of the book. You would then already know what difficult and easy topics will be presented; so you can then focus on the tougher parts of the lecture. You would then also be able to formulate your questions to the teacher more easily. Actually, even now, I see because I have asked a few times, and not many, just 10-15 %, students read before the class.

The perfect student, in my view, should always try to understand. You should have a passion for what you want to learn and your ambition should be to fully understand if it is within your capabilities. The goal is not to get a ten for the exam because the ten is so satisfactory, but it is satisfactory because you really understand the topic. I have always had problems with the mentality where people learn just enough to pass the exam because they don’t care to really understand the topic.

You mentioned that you wrote The Vonk during your student years, you also mentioned a bit about it earlier during the interview. Could you tell us a bit more about it?

It was about recreational mathematics, it was also one of my hobbies in those days. Nowadays, I don’t have too much time for it anymore.

Recreational mathematics is the kind of mathematics where you don’t really need to have a very high mathematics education level, for example puzzles. The very first article I wrote about was Can you think of a function where if you apply the function twice to itself you get the negative of the function itself, so a real-valued function f, such that f(f(x)) = -x? Another thing I wrote about was a Self descriptive sentence, that is indeed quite an interesting thing; for example, you could write a sentence This sentence has five As, two Bs, seven Cs, eight Ds,.. It should be exactly descriptive, so the numbers that are being mentioned should be correct. But how can you find such a sentence, so it is kind of puzzling. I sometimes also made a link with Electrical Engineering, for example, how many CMOS circuits can you make with x many transistors. Sometimes I also made puzzles with games. For a change, I would also publish short book reviews. I remember another thing that we made, which was something that was given to me by my mathematics teacher in high school, Can you come up with a mathematical formula which approximates the egg shape, that was around Easter.

The idea was that I was going to publish a puzzle one month, the students would respond with answers and the next month I would give the solution or the best solution that I received; but the response was very low, sometimes one or two persons, sometimes none. So gradually from making puzzles that required a response, I shifted to writing book reviews.

I also have a website of my own, where I have some recreational mathematics questions. The intention was to extend that collection with the puzzles that I made for The Vonk, but I haven’t really had time to do that yet.

As a last question, do you have any advice for the students?

My advice is try to enjoy your student years as much as possible. Try to learn as much as possible. The network that you build as a student, also from other faculties are useful, especially if you are going to look for a new job. I think studying at University is really a privilege, so make the best out of it. Develop yourself to always remain curious, also when you leave University and you are not going to come back to University, always keep your eyes open for new developments, because in the end that can give you a lot of satisfaction.