Margin in Software Systems

Margin of safety is a fundamental engineering concept where a system is built to tolerate loads exceeding the maximum expected load by some factor.  For example, structural elements of buildings typically have a margin of safety of 100%: they can withstand twice the expected maximum load.  Pressure vessels have more margin, in the range 250%-300%, …

Picking a Research Topic in Computer Systems

This post is a collection of observations and advice for people who want to choose a research topic in computer systems.  I’m not claiming to be some kind of genius in this area, but I have enough ideas that they seemed worth writing down. This advice is probably most useful for graduate students in CS, …

The Compiler Doesn’t Care About Your Intent

A misunderstanding that I sometimes run into when teaching programming is that the compiler can and should guess what the programmer means.  This isn’t usually quite what people say, but it’s what they’re thinking.  A great example appeared in a message sent to the avr-gcc mailing list.  The poster had upgraded his version of GCC, …

C and C++ Make It Hard to Read a Register for Its Side Effects

[ This post was co-written with Nigel Jones, who maintains an excellent embedded blog Stack Overflow.  Nigel and I share an interest in volatile pitfalls in embedded C/C++ and this post resulted from an email discussion we had.  Since we both have blogs, we decided to both post it.   However, since comments are not enabled …

Computer Science Fiction

Science fiction explores the effect of technological progress on society.  It is ironic, then, that the majority of SF authors miserably failed to predict the impact of computers and information technology. Why does Google return no meaningful hits for “computer science fiction?”  Is it not obvious that this term needs to exist, if we wish …

How to Evaluate a Computer Systems Research Paper

Some excellent resources exist about how to write a good systems paper. This post is about a slightly different topic. In a typical recent year I review about 100 papers, mostly conference papers 8-14 pages long in 9 or 10 point font. People in similar positions — mid-career computer systems professors — are generally in …