My Advice for ECE Undergrads

This is my personal and unofficial recommendations to an ECE undergrad.

I will continue to expand this page as time goes on. This page does not reflect the opinions of anyone else, and there is no guarantee of suitability. I believe every word I said, but that doesn’t mean you should too. This writing is informal, but please help me make this better by pointing out mistakes.

Copyright 2007~2021 James C. Hoe.

Advice about Advice

The most important advice about advice I already gave in the disclaimer above. (“I believe every word I said, but that doesn’t mean you should too.”)

When finding yourself in a new situation, getting good advice can be most helpful toward avoiding the very bad decisions and the avoidable mistakes. They are not so useful in making the “right decision” for you. (Don't confuse getting advice and letting other decide for you.)

When you ask for advice, it is important to understand what you are receiving. Most advice you will get is in the form of a retelling of personal experiences (possibly with embellishment and omissions). A more thoughtful teller may offer personal interpretation and insights on top of the narrative. In any case, an advice is highly personal and subjective to the teller. It behooves you to ask the same question to many experienced people. Find which answers are most relevant to you and your situation. At the end, you have to add your own interpretation and distillation to extract the “common knowledge” and “common sense” (that you lack because you are inexperienced) to help you avoid the known pitfalls. You still have to make the “best decision” for you yourself.

I do not recommend cloning someone else's success story; great successes are not repeatable exactly. The secret to success is luck; the non-secret is hard work, understanding what works for you, and avoiding avoidable mistakes.

Lastly, the best advice comes from first-hand experience. Beware of second-hand experts and their advice.

Theme

There is a very simple theme in my advising. The purpose of coming to study at CMU is to learn (about yourself and about an area of study); the purpose of learning is to know and to get to do what you want to do after CMU.

Know what you are working towards; start by asking yourself what you want to do after CMU if you don't know.

  • As a freshman, ask: which of what you have done is because you wanted to and not because “it was due”.
  • As a sophomore, ask: do you know what you want to do for the rest of your life. (It helps to exaggerate the perspective a bit.)
  • As a junior, ask: how does what you want to do fit into career and life after CMU.
  • As a senior, ask: what you should be doing next to achieve the career and life you want.

Your 4 years at CMU would have been well spent if you discovered what is it you really like to do and started to become good at it.

Course Planning

Degree Requirements

Degree requirements are not like levels in a video game. You don't win a diploma by simply clearing enough levels, one-by-one, as presented to you. (The diploma should never have been the objective in the first place.)

The degree requirements as a whole have the designed objective of preparing you for professional success after CMU by (1) initially helping you build a foundation of knowledge and breadth of exposure; (2) next helping you identify an area of interest; and (3) finally helping you start to specialize in an area of choice.

You need to view the requirement structure correctly and plan your undergrad study as a complete strategy from the start. You may have to do a lot of speculation, but even when deciding your first-year courses, you should have asked yourself what you want to do after CMU and what you plan to take in your senior year.

As you complete each course, do think about how it has (or failed to) build toward what you want to do after CMU; has it caused you to change your mind about what you want to do after CMU.

The same ECE degree requirements produce students of all kinds with different expertise and proficiency. Your future course is set by the expertise and proficiency you gain. The diploma is a glorified receipt.

Don’t Overload!!

Currently, you need 379 units for a BS degree in ECE (true as off Jan 1, 2020).

Without any AP credits, you should not have to take more than 4 courses per semester for 8 semesters. Most of you have AP units, so this means you could actually take less, or take 4 courses per semester that included other more “well-rounded’ courses beyond the 379 needed to graduate.

Regardless of what the policy says, as far as I am concerned, if you go beyond 4 “real” courses, you are overloading, and the quality of learning suffers. (There is a reason you see the prefix “over” in the word “overloading”. It is a warning that you are operating beyond the intended range.) Ask yourself, are you here to learn as well as you can or as fast as you can?

What most students do not realize is that there is typically more than a factor 2 difference (to be conservative) between the absolute performance of the best “A” student and the lowest “A” student in a course. Just because you got an A, you should still ask yourself, did you get as much as you can out of that course? If you are taking 66 units, you don’t have time to get as much as you can out of your courses.

You might be tempted to think by overloading you are getting more “units” per dollar (of tuition) out of CMU. Don’t confuse that with how much learning and retention you are getting for your dollars. Overloading is not worth it.

What courses to take (last updated 4/23/2019)

There are so many different courses you could take as an ECE undergrad at CMU. This can get really confusing. The suggestions below are simply a representation of what “I” would have taken had I been an undergrad in ECE today.

ECE Pre-Core

  • 18-100: Introduction to ECE (12 units)
  • 18-200: Emerging Trends in ECE (Sophomore Seminar) (1 units)
  • 18-202: Mathematical Foundations of Electrical Engineering (12 units)

ECE Core

  • 18-220: Fundamentals of ECE: Electronic Devices & Circuits2 (12 units)
  • 18-240: Fundamentals of ECE: Digital Logic & Computers3 (12 units)
  • 18-213: Introduction to Computer Systems (12 units)
  • 18-290: Fundamentals of ECE: Signal Transmission and Processing (12 units)

I strongly discourage anyone from taking more than 2 core courses in a semester. It is not a goal to finish all 4 core courses in your sophomore year. Take them in the order of your interest so you can get to the right 300-level courses sooner.

ECE Breadth

  • 18-320: Microelectronic Circuits (12 units)
  • 18-341: Logic Design Using Simulation, Synthesis, and Verification (12 units)

ECE Concentration

  • 18-447: Introduction to Computer Architecture (12 units)

ECE Coverage

  • 15-410: Operating System Design and Implementation (12 units)

Capstone Design

  • 18-500: ECE Design Experience (12 units)

Other

There are still the Free Electives. They should not all be technical, but it does give me the time to take a few more courses (without overloading). Here are examples of some courses I would consider choosing from (as a student interested in computer architecture).

  • 18-340: Hardware Arithmetic for Machine Learning
  • 15-411: Compiler Design
  • 18-422: Analysis and Design of Digital Circuits
  • 18-740: Graduate Computer Architecture

I would be tempted with

  • 18-330 Introduction to Computer Security
  • 18-349 Introduction to Embedded Systems
  • 18-403 Microfabrication Methods and Technology (this I actually did as an undergrad)
  • 18-461 Introduction to Machine Learning for Engineers
  • 18-464 ULSI Technology Status and Roadmap for System on Chips and System in Package

I would make it a point to take a few fun, non-ECE courses (freshman-level intro courses are just fine).

I would also include a senior project. If I were interested in going to graduate school, I would start my senior project the summer before the senior year. I would not try to do undergraduate “research” during the semester with a full course load. Lastly, I would do a technical internship in the industry the summer before my junior year.

I do not recommend undergrads (especially if heading to PhD) to hurry into or take a lot of graduate courses. You do want to take THE one in your specialization (18-740 in my example) before you apply for PhD. (Okay, may be just one more, 18-643.) As IMB, I trust you are mature enough to pick what you need and what is good for you for whatever you have planned for your own career future.

Again, this simply reflects what I would have done as an undergrad. If you don’t like what you see here, don’t be shy about asking another professor closer to your area to tell you what he/she would do.

Depth and Breadth

In general, I advise students against the strategy of “I am interested in X, and therefore I am going to take every course CMU has on X.” (To simplify this conversation, I assume you are without any doubt interested in X. You would be surprised how often even this basic assumption fails to play out.) Courses can only provide foundation knowledge; you do not become really good at X from taking courses. In your time at CMU, certainly you should take courses in your chosen area of specialization, but how valuable is the N+1 course after having taken N courses already? Are you not going to be better off doing a research project? (After all, once properly prepared, doing things on your own is how you become really good at it.) Furthermore, think harder about what other topics you might also be interested in or can supplement your career objectives. It may be counterintuitive, but, to become an expert on X, you are going to need to know a lot more than just X.

Should one double major in ECE and CS?

I am assuming this question is asked by someone who is interested in the computer systems area (think 18-213/15-213) that is in this overlapped region between ECE and CS. If someone in applied physics or theory is asking this question, come talk to me directly; I am curious to meet you.

What is clear is that a systems person should absolutely take classes from both ECE and CS. Beside basic data structures and algorithms, topics like OS and compilers are all par for the course. If so inclined, taking a course in theory or programming languages is helpful with acquiring a new way of thinking that does not come naturally to a systems person.

Separate from my recommendation to take courses from both departments, I don't see any good reason to go through the trouble of achieving both degrees. The more competitive you are as you advance in your study and career, the more you should expect to be judged by what you can do and not what your credentials would suggest you should be able to do. For the best jobs and graduate schools, they will figure out exactly how good you are in a hurry, and no one is going to care whether you have CS or ECE or both degrees.

I am however a proponent for double-major or minor of very dissimilar disciplines (Business, Drama/Art/Music, Sciences…) if you are driven to do so by your unique interest, talent, or goal, and not for trophy hunting.

Studying Effectively

How to "do well" in school

I assume all of you have the mental “horsepower” if you are at CMU in the first place. It is easy to do well if 1) you enjoy what you are studying AND 2) you apply good study “mechanics”. If the former is false, you have a big problem. But, the latter just takes discipline (see next).

Studying correctly will make learning more pleasant and productive—all the while taking LESS (not more) time. Nothing is more frustrating (and a big waste of time) than showing up to a lecture and not understanding what the professor is talking about. (Did you do the reading assignment beforehand?) Nothing is more frustrating (and a big waste of time) than struggling on a homework assignment that you fundamentally have no clue about. (Did you wait until the night before the deadline so you cannot get help in office hours? Did you skip the relevant lecture in the first place? Did you do the reading assignment?) These unpleasant scenarios and others like it can be avoided if you had the discipline and mechanics to do the right thing in the first place; trying to make up afterwards is a forever up-hill battle. Every topic you don’t understand well now will make it that much harder to understand the next topic that depends on it—don’t let it snowball.

I often get asked by students (even seniors) the question “do I need to know X for the exam.” This is a sure sign that this student is still under the high-school’ish mentality of studying for grades rather than studying to learn. Ask instead the question “do I need to know X if I want to have a career in Y.” Similarly, when you receive a low grade in a course, worry less about how it impacts your GPA; worry more about what the grade is telling you—you didn’t learn the material as well as you should or as you thought you did.

To goal to “do well” is to have learned well. Getting good grades is only a symptom.

Study Mechanics Simplified

  • Care about the subject you are studying
  • Do the reading assignments before lecture
  • Attend lectures (and pay attention)
  • Ask questions when you don't understand
  • Do homework or lab with intent to learn (not simply to produce something to turn in for points); don't wait until the last minute to start
  • Have a place where you can work without distraction
  • Get enough sleep, eat healthy, and exercise

Seems obvious, no? Easy to follow through? No.

Figuring out what is important

When I look across a class cohort, the most telling difference between the thriving students and the struggling students are their ability to recognize what is actually important. This comes across both in the answers they give and in the questions they ask.

An important part of collegiate maturation is to learn to recognize what is actually important. Focusing on the unimportant is against Amdahl's Law.

Calling Amdahl's Law a “Law” is no exaggeration. No effective optimization can violate Amdahl's Law. If you are working very hard but not getting the desired effect, double check what you are working very hard on.

Asking questions in class

It always puzzles me why I don't get more questions in class. I know I cannot possibly be getting through to everyone all of the time.

Rule of Thumb #1: If the professor said something that doesn't sound right or is not clear, there is a pretty good chance he/she overlooked to explain some important detail/assumption or made an outright mistake (yes, it does happen, and no, we are not always testing if everyone is awake).

Rule of Thumb #2: If the professor said something that doesn't sound right or is not clear, there is a pretty good chance the rest of the class is confused by it too.

In both cases, it is your duty and privilege to ask for clarification. (Caveat: this works much better if you went to lectures prepared, i.e., having done the reading assignments.) If you were wrong about it, it is better to find out then and there.

Reviewing for Exams

You cannot really “study” for a final in the last minute. If you really could make a big difference by cramming in just the days before a final, we wouldn't need semester long courses. You can only “review” before the final what you studied and learned over the whole semester.

A great way to review for a final is to work out old “practice” exams. The most effective way to do this is to finish reviewing first and then test yourself with the practice exams to see how prepared you really are. (If you are not prepared, keep studying.) It is useless to study an old exam itself; it is even worse to study an old exam's solutions. Keep in mind, it is not good enough to understand the solutions; you need to be able to come up with the solutions without prompting. It is not good enough to know how to do those exact problems; you need to be able to solve problems of the same nature in general.

Lastly, I often see students studying lecture slides. Lecture slides contain very little information on their own; they are more like mental tabs to remind you of what was said in the book or in the lectures. If you have not read the book or did not attend the lectures, there is very little you can extract on your own from the lecture slides themselves. If you are not doing the reading assignments or you are not attending lectures, then you are really missing out on learning.

Responding to an Exam Question

When you see an exam question, you should first reflect if you know the answer or how to answer. Occasionally, you may find your knowledge gap is large enough, you don't understand the question.

When responding, you should know for yourself if you are giving an answer or a guess. (Ironically, the less you know the difference, the more obvious the difference is in the eyes of the grader.)

Except for “honest” misunderstandings you hold, you shouldn't need the answer key or graded papers to know you don't know. It is the same when doing homework.

Do something about the weaknesses exposed by the exam questions (even if it is the last final of your last term at CMU).

See also this related comment.

Miscellaneous gripes:

  • A not-false statement is not the same as a correct response. There is no partial credit for answering “1+1=2” to “What is the meaning of life?”.
  • A correct answer to the wrong question is the wrong response. There is no partial credit for answering “1+1=2” because you assumed or misunderstood “What is the meaning of life?” as asking “What is 1+1 equal to?”
  • Unless the entire class answered “1+1=2”, not able to understand the question is a part of your assessment.
  • Having the “text” of the correct answer enveloped in a novel of drivel is not a correct response. You can't get full credit for the answer, “A hundred prisoners are each locked in a room with three pirates, one of whom will walk the plank in the morning. Each prisoner has 10 bottles of wine, one of which has been poisoned; and each pirate has 12 coins, one of which is counterfeit and weighs either more or less than a genuine coin. In the room is a single switch, which the prisoner may either leave as it is, or flip. Before being led into the rooms, the prisoners are all made to wear either a red hat or a blue hat; they can see all the other prisoners' hats, but not their own. Meanwhile, a six-digit prime number of monkeys multiply until their digits reverse, then all have to get across a river using a canoe that can hold at most two monkeys at a time. But half the monkeys always lie and the other half always tell the truth. Given that the Nth prisoner knows that one of the monkeys doesn't know that a pirate doesn't know the product of two numbers between 1 and 100 without knowing that the N+1th prisoner has flipped the switch in his room or not after having determined which bottle of wine was poisoned and what colour his hat is [ classic Click-and-Clack "drivel" ], . . . . . . we should leave the world a better place than we found it . . . . . . .”
  • It is possible to do worse than being wrong.
  • It is possible to be wronger than wrong.

On grades and cheating

My second least favorite duty in teaching is to assign grades. My least favorite is to deal with cheaters. I talk about them together because my objection to them stem from the same root problem—the need to understand the real objective of taking a course.

Grades: It troubles me greatly that some students put so much more emphasis on getting the grades over actually learning the knowledge. Some degree of this is difficult to resist (e.g., cramming the night before the exam), but we all know what this can also mean when taken to the far extreme.

You would do much better if you worked on learning the materials. Your grades reflect how well you have learned and not the other way around. One day you will leave CMU and will have to make a real living with what you have learned; your GPA and diploma can offer little solace to you or your boss if you cannot perform on the job.

The A/B cut-off is a perennial point of contention at the end of a term. Keep in mind, if you are performing near the boundary between A/B, (1) whether you receive an A or B, subject to noise and chance, is a correct outcome (don't be there); (2) whether you receive an A or B, it does not change how well you have really done and how well you will be able to do in the future (don't stay there). The purpose behind taking a course doesn't end with the term and letter grade.

Cheating: For anyone even contemplating cheating, you should understand it is just not worth it. First of all, cheating cannot fix the fact that you really don't know or aren't able to do what you will need in the subsequent courses and in your later life. Second, although the chances of getting away with any one isolated instance of cheating is typically quite good, any one incident is also unlikely to have a noticeable positive impact on your semester letter grade. For that, one has to be cheating systematically, and one will surely get caught for that. Third, think back to when you were little and how your mother could always tell when you lied. She couldn't read your mind; you were just more obvious than you think. By watching a student over the course of a semester, we (professors) have a very good sense for what is a student's expected performance and trend. You will get the grade you worked for.

For someone who is feeling the pressure to cheat, the wrong thing to do is to succumb (obviously). The right thing to do is to recognize it as the warning sign of a deeper problem. Somehow you have let your study fall behind and out of control. If you continue the same course, your problem will only snowball. The only way to recover is to identify the problem and to change what you are doing to regain control. Cheating is a poor patch job that does nothing to fix the root of the problem. I encourage everyone to take a look at this very helpful page on how to avoid being caught up in this bad situation in the first place. (Notice their suggested way to address academic integrity is to do better in the first place so there is no reason to consider cheating. I fully agree with this.)

I use the following definition in my course syllabus: “To put it plainly, if what you are about to do is not a truthful reflection of your knowledge, ability and effort, you are about to cheat. More importantly, if what you are about to do is going to get you a better grade without helping you learn the course material, you are about to cheat.”

The real meaning of A-/B+

This of course applies also to B-/C+, C-/D+, etc.

There is no difference in the meaning of A- and B+. If you get an A- or B+, either way, you are good but there are those in you peer who are decidedly better in that particular course.

It makes no difference if it is recorded as plain A or B on the transcript, you ARE still that “you”.

If term after term, you find yourself near the cut-off for A- and B+, don't be surprised with a 3.5 GPA in the long run. Then again, keep in mind, maintaining a 3.5 cumulative GPA is very good—not just good—and means something quite different from receiving one A-/B+ one time in one course.

Don't fixate on getting over the grade cut-off. Set your sights on improving, whereever you are.

Homework Assignments

Undergrads, even some seniors, often misunderstand what homework assignments are about. (See my earlier comment on getting out of the high-school mindset ASAP.) Instructors do not assign homework because we see the necessity to take up your time or to have something to grade.

Homework assignments (especially in upper-level courses) are given as exercises for you to actually work with what you saw in the lectures or read in the text. This is one more chance for you to catch the difference between what you think you understood and what you really do. (The homework assignments from your younger days were drills to become good in basic skills.)

Even in an ideal world with ideal students, I would not do away with homework because it is an effective teaching/learning tool. In the ideal world, I would give out homework (and provide solutions) with no consequences on grade. (Then again, in the ideal world, I wouldn't have to assess grades to begin with. You learned what you learned; you make do with what you learned.)

If you ever find yourself rushing through homework the night before it is due (even though it covers multiple weeks of past materials and you had weeks to do it), stop and rethink your strategy and mindset. You could do it anytime—before or even after the due date—for the same learning effect. Why did it suddenly become important the night before it is due? (BTW, if you have skipped reading assignments because you are not directly assessed on it, see above.) Still worse, if you ever resorted to “cheating” to finish a homework, you really need to ask yourself why and what for.

Do homework to learn from it not to finish it.

What does it really take to do well in a course

The following is real data correlating homework points (worth only 20% of final grade) and final course performance. Multiple choice:

a) higher homework grade (worth 20%) causes higher final grade.

b) higher performing students are better at doing homework (but everyone could get help in office hours and piazza).

c) doing homework carefully causes one to learn deeper, work out better solutions, get better course grade, and actually be good at what the course is about.

d) wanting to learn causes a student to….

Homework performance is a pure reflection of learning for learning's sake. Everyone has the time and resource to work out the perfect solutions, but it would not be worth the effort if the motivation is a better grade.

How much of what you do for a class is on your own volition and not for assessment?

Why grade on a curve

In basic courses (think grade-school arithmetic but really any rote knowledge or skills courses), there can be a finiteness to the learning objective. On a test with 100 addition examples, if you produce all of the same sums as the answer key, you are “perfect”. Anyone who gets more than 90% right is considered pretty good. If we give everyone a calculator, almost everyone will be pretty good.

In an upper-division college course, that isn't the case.

Take 18-447 (computer architecture), even if you can memorize the lectures and the textbook verbatim, can you design a good computer to requirement. Can you set good requirements?

Even with the ability to google search the entire indexed human knowledge, not everyone will be good at coming up with the “right” computer design. Not everyone will even be equally good at coming up with fruitful google queries (i.e., asking the “right” questions). The difference is in how well one understands the fundamentals and is able to synthesize anew.

There is no 100% mark for what we do in 18-447. There is no answer key to the problems you learn to solve in 18-447. Good or bad is relative and only a matter of competitiveness.

Learning on Your Own

In the acquisition of knowledge, there is a point where any more advanced material is simply inaccessible to you. Don't worry about that; almost no one ever get that far anyway.

Long before that though, there is a point where the sophistication of the material cannot be taught anymore. (Ask my PhD students. They will freely attest that I teach them nothing.) Anything beyond that point, you can only learn on your own.

You are nearing that point. Whether you advance beyond that point, is only a choice of wanting to learn, and, for many of you who never considered it, the realization that you can learn on your own. This is equally applicable to an academic or industry career future.

Don't stop learning after CMU. Learn to learn on your own. In learning on your own, you might just learn something that no one else has learned before.

"It doesn't work."

Asking for and getting help on Piazza is very powerful. Reading other people's questions and answers is itself a valuable source of good insights. You probably have also seen Piazza posts declaring no more than, in effect, “My lab doesn't work,” usually too close to when the lab is due. Without providing more information, it is very hard for anyone to help.

Take responsibility for YOUR problem.

The more you can narrow down the problem to specifics (from the blanket declaration “It doesn't work”) the more likely that someone has a quick answer. Share what you have tried already to diagnose the problem. Do you have any hunches? What is the last thing you did before your lab broke?

Of course, always read the lab handout and follow the instructions correctly—if it worked for everyone else, what did you do different? Do try “googling” for the answer. Then, some debugging problems are just too involved for the quick back-and-forth format of Piazza. Start early to run into the problem early so you can take your problem to an office hour. If you are starting a lab without a firm understanding of the course material covered, study the course material first.

A level of due diligence in diagnosing the problem on one's own first is an important self-discipline. The ability to debug is a prime trait of a good designer/engineer. It is all part of problem solving.

You might be a freshman . . .

  • if you come to CMU to get a degree.
  • if you study for grades or take classes for requirements.
  • if you don't need a textbook because you go to lecture.
  • if you don't go to lecture because you read the textbook.
  • if you don't need your textbook anymore after the course is over.
  • if you ascribe significant difference to the meanings of A- vs B+.
  • if you ask, “is X covered on the midterm?”
  • if you work on homework and lab to “finish” them.
  • if you study differently in the first week and the last week of the semester.
  • if you see a problem in having 3 midterms on the same day 3 weeks from now.
  • if you don't know your current course instructors by name.
  • if you never had a 2-way exchange with an instructor.
  • if you never spoke with an instructor on something not about the course.
  • if you assume everything you read in a textbook or hear in a lecture is unimpeachable.
  • if you can't follow instructions in lab/project handouts.
  • if you can follow only exact instructions in lab/project handouts.
  • if you don't know how to approach a problem with more than one acceptable solution.
  • if you don't know how to approach a problem with multiple competing objectives.
  • if you don't know how to approach a problem that does not have a good solution.
  • if you never answer “I don't know” to a question.
  • if you are never the reason why things didn't work out.
  • if you are never #2 because #1 is just better at it than you.
  • if you have never done anything not asked of you.
  • if you have never finished anything before it is due.
  • if you want to be an “Electrical and Computer Engineer” after you graduate.
  • if you do not think about what you want to be doing 5/10/15 years from now.

So you want to be a hardware person

What is the study of Computer Architecture?

You may have heard that computer architecture is the interface between hardware and software. Actually, it is more generally between how computers are used and the technologies to build them.

Think back to 18-213, the computer you thought you knew is actually an abstraction—propped up by the programming language and the operating system, you never touched the computer. In 18-240 you learned how to build many interesting hardware building blocks, but you may not yet appreciate the universe of things you can assemble from them. If you ever wondered what happens between 18-213 and 18-240 in the making of a computer, you need to study computer architecture. (How to design a processor is only one of the things covered there.)

Ultimately, to be a computer architect is to be someone who understands what computers do and, in a principled way, knows how to do it well under the ever-changing technology and other constraints.

Evolution of 18-447 over time

You can compare the current 18-447 lectures to 2009 (when we dropped computer arithmetic and added parallel computing). There is about 60% overlap in topics; about 50% overlap in slides.

It is quite interesting to see how much an undergrad course had to evolve in just 10 years. We are in an exciting field during an exciting time.

It is also interesting to look at the materials that hasn't changed the slightest, to ask (1) why the staying power (e.g., von Neumann) and (2) is it time to revisit things (e.g., making programmable logic a fixture in computer organization).

Designing hardware is not hard; designing good hardware is.

Slow hardware is as easy to develop as slow software.

Among all design solutions that correctly meet the same functional specification (give the right answer), a design can be judged better or worse by deployment-specific metrics of goodness, encompassing any combinations of performance, power/energy/thermal, cost, weight, size, noise, and anything else one might care about besides computing the right answer.

Designing hardware is not inherently more difficult than programming. Designing good or even just good enough hardware can be.

It's just that we never design hardware just to be correct. If you are ever asked to implement something just to give the right answer, do it in software. Even if the good-enough bar is raised, as long as you can do it well enough in software, you should keep doing it in software. You should only contemplate using hardware on problems that are too hard for software. May be in that sense, one could say hardware is harder than software.

I don't understand why people expect high-performance HW design should ever become easy when performance has never been easy in software (except in certain bounded domains where domain-specific knowledge can be neatly packaged into tools). I do think HW design currently suffers from being unnecessarily hard—from poor use of abstraction and tools that don't always work as advertised. These unnecessary difficulties (that RTL designers somehow all agreed to put up with) need to be removed. That still will not make performance and efficiency easy (except with domain-specific tools with carefully selected the degrees of freedom in design input and output). Really good designs require inventiveness and creativity that is not even always teachable to another human being.

Amdahl's Law Quiz.

True or False:

An instruction opcode X is used infrequently in an embedded workload (less than 1 in 500 executed instructions). Amdahl’s Law would say NOT to worry about optimizing the executions of instruction opcode X on a processor designed specifically for that workload.

(!eslaf si sihT)

Planning Ahead

Undergraduate Research Opportunities

It is very good to do undergraduate research, especially if you are planning to go on to graduate school. It will give you a taste of “research”, and it will give your research advisor something concrete to write about in the recommendation letter (if you do a good job that is).

I typically advise undergraduate students against doing formal research projects during the semester (where there are hard commitments or you are graded). Undergraduate course work is hard enough at CMU. Try to do both at the same time, at least one side is going to suffer. (Experiences say undergraduate students will prioritized course HW, projects and exams over research since research project usually don't have set week-to-week graded deadlines.)

This doesn't mean you shouldn't do things outside of classrooms. Look into, for example, Build 18 (http://www.build18.org/), the Robotics Club, the Mobot Race. It is also just fine to think of something cool to hack together on your own. Especially during the semester, you should look for things that are relaxing and fun to do but won't add extra pressure to your course load. (If you say “but I am already doing well enough and still have all this time”, see what I have to say about overloading. If you are really that good, you really should try to do still better.)

I strongly recommend you (undergraduate students) to try out research during the summer when you can devote the time and really get something out of the experience. You have to have realistic expectations though. Many of our freshmen and sophomores are already very skilled in programming and may be even hardware design, but “research” is about a lot more than development skills. The more courses you have taken, the more you will develop the maturity of thinking and the depth of understanding that are needed for productive research. In the earlier years, look around for “projects” (as opposed to research) opportunities. There are a lot of projects on campus that could make use of good programming or hardware design skills.

The summer after your junior year is the ideal time to do a research project; make sure you have taken the key Depth course in your area of interest by then. (For example, if you are interested in my work, the key course to have taken is 18-447.)

Approaching a Professor for Research Projects

As noted above, you will be much more likely to succeed in securing a position if you approach the professors with very specific goals and a little bit of track-record. Do not do the following.

  • Do not send the same generic email to multiple professors. Do not tell a computer architect how you are very interested in nothing in particular or something not computer architecture. You are not going to get a position by saying “I am very good at everything;” “I will do anything;” or “just give me something to work on.” In general, professors are not looking for availability of labor; we are looking for a genuine interest and commitment.
  • Do not contact a professor if you don't already know what he/she does. Visit his/her research website; read a few papers. It helps a lot to be able to say something specific and to offer some ideas of what you would like to do.
  • Do not be unprepared to answer the question, “why do you want to do a research project?” (An honest answer like “I need the units to graduate” will work in some circumstances.)
  • Do not leave out your resume on the initial email (or not have it when you visit). There may not be a second exchange; get your foot in the door.
  • Do not be invisible or do a mediocre job in a course then ask the instructor for a position at the end of the semester.
  • Do not be fixated on a particular project or a particular professor.

As with many other things desirable and scarce in life, persistence, patience, and boldness count in getting what you want. Don't be discouraged if you don't hear back or gets turned down. Try, try again. On the other hand, you do have to have something real to offer when you approach a professor. Your own eagerness or desire is not enough; you will not get anywhere if you are not willing to invest the time up front to brush up your resume, to investigate the research opportunities, or to do an impressive job in a course.

Doing Undergraduate Research with Me

I do work with undergraduates on research. Almost without exceptions, the following are true.

  1. The student is planning to go to graduate school.
  2. The student is interested in computer architecture and hardware.
  3. The student has taken 18-447 (and done well).
  4. The student has substantial experience with C (or some other programming language) AND Verilog (or some other HDL).
  5. The student is available for full-time research (for pay) in the summer before the fall of her/his graduate school application.

I only have resources to work with 1 or 2 students each year. So I prioritize heavily for those who fit the above criteria. I have stopped working with undergraduate students during the academic semesters, except 1. someone continuing from a summer project, or 2. someone who just needs a “consulting” mentor for his/her honors senior project of his/her own design. I am generally very willing to talk to you (CMU undergrads) especially if you come during my posted office hours.

Going to Graduate School

Going after a PhD is not a small decision. Go talk to a professor in your area of interest. Make sure you understand what it is all actually about. Also, you should read this.

You can apply before you commit, but before you commit to studying for a PhD, ask yourself this one important question, “what do I plan to do afterwards that requires a PhD?” Don't start if you don't have an answer. There are no industry positions out there where having a PhD degree, in and of itself, is a necessary or sufficient condition. (If you need inspiration.) If you want to become a “professor”, make sure you know what professors actually do. I am in front of a class for only 4 hours a week; most of what I do is not visible to a casual undergrad.

While you are deciding, find out which school and professor is working on what in your area of interest. For computer architecture. find the conference proceedings for ISCA, MICRO, and HPCA at IEEE Xplore. Skim through the paper titles of recent conference papers and see what topics interest you. Try to read a few papers; even if you can't understand every detail in a paper, you should be able to get a good sense for what the work is all about. Try starting your search with the International Symposium on Computer Architecture (ISCA). (Every field has 1 or 2 premier conferences. You should know—or get to know—what those conferences are for the field you are going into.)

Asking for graduate school and fellowship recommendation letters

Rule #1: Unless the professor knows you by name without prompting (and for good reasons), don’t bother asking him/her for a letter. Rule #2: If a professor appears reluctant to write you a letter, it is little use to try to persuade him/her. An impersonal, lukewarm “form” letter will not help and may actually hurt your case. If you know you are going to need recommendation letters in the future, start building relationships early. A good letter is earned.

For formal letters, make sure you ask your letter writers at least one if not two months ahead of the deadline. Be sure to provide very clear instructions to your letter writers. Provide pre-addressed and stamped envelopes if appropriate. Remind your letter writers again a couple of weeks before the deadline. If possible, take it upon yourself to verify the letters have been received by the destination.

Asking for job application references

Much of the above still applies, but references for industry jobs are much less formal. Be sure to ask for permission before you list someone as your reference. It is customary to just say “Reference available upon request” on your resume. Usually companies won’t even bother to ask you for your list of references until after you have gone through a first interview and done well.

Answering every question

Many undergrads are conditioned to answer every question, whether they know the answer or not. This may be okay on an exam since the consequences are lower bounded to not getting any points.

You should be aware that, even on an exam, the professors and the TAs are forming an impression about you based on how wrong the answer is. There can be consequences beyond the exam and the course. A baseless answer that reveals deliberateness in construction is that much more telling than simply guessing incorrectly.

Out of school, on any kind of interviews, in making up an answer to a question, you are sharing with the interviewer much more than the question's intend assessment scope, without lower bounds. Don't risk giving an answer that is "not even wrong". If you don't know the answer, don't feel compelled to give one. Saying you don't know sets a lower-bound.

Even more dangerous, giving an answer you don't know to be correct in real-life situations has real-life consequences (think, doctors, bridge designers, teachers, etc.).

See also this related comment.

Miscellaneous

Do you have the knack?

College is all about finding your knack.

I am worried about my grade

Hopefully you don't know anyone like this.

Any Questions?

Didn’t find the answers you were looking for? Try emailing me the question directly. How to contact me.