jsulz


Fueled by coffee, code, and spreadsheets

The Engineering Art of Balancing Desire with Reality (as told by processor caches)

In a course about high performance computer architecture, it’s no surprise that most of the time is spent discussing how to speed up computers using their architecture. It’s almost as though the name of the course tells you exactly what to expect.

This week in CS6290 at Georgia Tech, we’ve moved on to caches, which play a key role in speeding up the retrieval of information. The processor’s goal is crunching data which is held either in main memory (RAM) or on the disk (an SSD or HDD). To get that data, the processor issues requests for memory addresses and retrieves the data from the memory storage unit that holds that information.

Processor Pipelines and the Foundation of Computing Systems

This will probably be my last semester at Georgia Tech that includes a computing systems course (unless high performance computing becomes available again online). The rest of my coursework will be focused on my specialization – machine learning – and while I’m excited to focus more on the questions that brought me to this program, I will undoubtedly miss computing systems.

The beautiful part of this area of computer science is that it is where the rubber meets the road. Theory meets application and provides lessons to feed back into theory which then feeds into other applications.

Everything In Its Right Place – A Primer on Hardware Support for High Performance Computer Architecture

My wife and I have a running joke in the house when either one of us moves something to its “correct” resting place, usually punctuated by breaking out into song.

Computer science is the practical application of many other sciences (solid state physics, calculus, linear algebra, information science, etc., etc., etc.), but it is at its most exacting and least forgiving the closer to the hardware you get. Here, everything truly does have its right place.

Checklists Are Important for Everything – Especially Processors

Every so often, a few posts come across my desk at the same time, and it reminds me of how at some basic level, all work is the same work, just manifested in different ways. Checklists and agendas, which are near and dear to my heart, are crucial for communicating and getting things done correctly across a team. They represent an agreement, a contract, reflections of expectations.

When you enter a meeting that has gone off the rails, it’s likely that either someone has torpedoed the agenda or one was never established. Likewise, any time I’ve needed to get a project back in a manageable state, a forced prioritized to-do list is my weapon of choice.

Similarly, sequential logical steps are the bread and butter of processors. Most of my high performance computing architecture course is focused on how processors squeeze every possible optimization out of a program’s instructions. There are dozens of ways that it does this (branch prediction, loop unfurling, data caches, etc), but perhaps most approachable is how a processor issues and executes instructions.

A GT OMSCS Course Review – Advanced Operating Systems (CS6210)

For my first semester at Georgia Tech, I wanted to take two courses that were well-reviewed, challenging, and introduced me to new concepts but that also played to my strengths. The first two months of the semester were bound to be hectic as I balanced gracefully leaving my full-time job of the past 6+ years with starting OMSCS. With that in mind, I ended up taking both of the operating systems courses GT offers online students.

Fortunately, there was only some overlap between the two courses and once I was a full time student my schedule made it easy to cram on the sort of “presumed knowledge” that Advanced Operating Systems (AOS) assumed was rattling around in my brain. There is also a “refresher” course that I would strongly recommend going through if you’re taking this course without GIOS. It’s possible to complete in a weekend and the first week of the course is a perfect time to cram this in. Going through this refresher and honing in on areas of weakness had the added bonus of forcing me to learn topics that pushed me ahead of the curve in a few areas in GIOS, but not so many to make that course redundant.

Similar to GIOS, the course professor (Umakishore Ramachandran) provided excellent lectures with a well-structured course, but was largely absent from managing the day-to-day of the class. While the TA’s in this course were less active than in GIOS, they still capably managed all forum questions and were readily available in Slack. There are four projects (one of which is essentially a warmup for the last project) and two tests. The projects are manageable if you have C/C++ skills, and I found the tests to be easier than those in GIOS (more memorization on these tests and less applied concepts).

A GT OMSCS Course Review – Graduate Introduction to Operating Systems (CS6200)

Georgia Tech’s Graduate Introduction to Operating Systems (GIOS), a thorough review of the core concepts behind operating systems, came highly recommended by way of OMSCentral and it did not disappoint. The lectures (delivered through Udacity) are well-structured and concise, the projects are enjoyable and go beyond the normal client/server projects in an undergrad OS course, and the course TAs and community are key to making this a top-notch experience. In summary, if you have decent C/C++ experience and either have not taken an operating systems course before or it’s been quite some time since you looked at these dinos, then I’d strongly recommend signing up for CS6200.

Ada Gavrilovska is the course professor, but most of your interactions (asking questions about projects, tests, readings, etc.) are with her teaching assistants. Fortunately, one of the fun parts of OMSCS is that most students and TAs are full-time employees themselves. This means that while the course is driven by TAs, these folks have real-world experience to bring to the table, usually from similar areas of practice.

A Full-Time Student

My first day with LexBlog was sometime in August of 2008. The previous summer I worked at a Hastings (a now, mostly defunct retail chain for movies, books, video games, CDs, and okay coffee), my last retail job. LexBlog, by way of Colin O’Keefe, provided me a route to take the first steps in my career with a part-time editorial position. I began by working on their content aggregator, LexMonitor, covering the work of the largest law firms in the country.

Fast forward eleven years and LexMonitor is a thing of the past at LexBlog, as am I.

On September 26th I walked out of a WeWork in downtown Seattle on what would be my last long walk home after a day at LexBlog. The walk was about five miles, something I’d done countless of times since moving to Seattle in 2013 to work for LexBlog full-time. It was a walk reserved for thinking through especially hard problems or after a long night (and sometimes early morning) of work. This time, it was a walk into a new branch of my personal and professional life.

Working Remotely in Anchorage, Alaska

My morning routine is sacrosanct. Every day, I wake up at the same time, drink the exact same amount of coffee (which is usually just a little too much), take the same bus, and settle into work. I find a great deal of comfort in this routine, which is why the lack of shock to my system over the month of August was itself quite a shock.  On Sunday, July 28th, my wife and I flew up to Anchorage, Alaska and settled in a small Airbnb on the outskirts of town.

This was not a permanent move; in fact I’m already back in Seattle. Our time in Anchorage was limited to a month as Sarah wrapped up a rotation at the Alaska Native Medical Center (ANMC). While her routine was shockingly similar (which is to say, “brutal” – residency is no joke), mine was very different. Gone was the morning commute to the office. My french press had to stay at home, and the view from my office became dominated by a forest filled with vegetation and the occasional moose.

Technology Advances; the World Remains the Same

I do not own a desktop computer and have not for nearly seven years. Before that, my primary computer was a Dell desktop that my parents bought me as a college graduation present that I augmented with a small notebook computer (at a time when such small laptops were just a novelty).

Even without a desktop computer, my life is full of peripheral devices. Laptops these days are so powerful that most can easily accommodate an additional monitor (if not two), and working in this way usually requires a detached keyboard and mouse.

Today, my mouse’s batteries died. Unlike my keyboard, which is solar powered, my mouse runs on rechargeable batteries, and I often forget to recharge them. When I do, I’m left with just my laptop’s trackpad and a sense of frustration.

Finishing One Degree; Starting Another

This summer, I’ll wrap up a computer science degree from Oregon State University. The experience has been rewarding, difficult, and incredibly eye-opening.

After the first quarter at OSU, I was not sure that the program was for me. While learning C++ was a nice wrinkle, the “Introduction to Programming” courses that served as my welcome were underwhelming. In hindsight, this perspective makes sense as someone that was coming in with years of experience managing and delivering web projects for large clients with large expectations. Learning the structure of for loops, classes, and a brief dalliance into recursion was not really what I had signed up for. However, after the fourth quarter I was trying to plot a path to continue my education far beyond the 15 courses that were required to get another bachelor’s.

It wasn’t the fact that OSU continued to underwhelm that drove me to look beyond the program – quite the opposite. OSU provided a window into a world that I didn’t know existed. It’s fair to say that two years ago I did not know what a computer science degree entailed or what it prepared you for. Two years later and I can’t imagine a world where I don’t continue to explore the field.