composition.al

s/S/C/

It’s been nearly half a year since it happened, so it’s probably about time I mentioned it: the group I originally joined at Intel Labs, the Programming Systems Lab or PSL, has been absorbed into a larger group, the Parallel Computing Lab, or PCL. I was a proud member of the PSL, and it was a little sad to lose our old lab’s unique identity. However, joining the PCL has been a good thing for me and for us. Our old projects continue; in particular, the PCL is now home to the High Performance Scripting project, which ParallelAccelerator is a part of. Some of our PCL colleagues had been involved with Julia already, so it makes sense that we’re now in the same lab and can more easily coordinate our efforts.

The first ten minutes of my JuliaCon talk

Last week, I presented a talk at JuliaCon 2016 about ParallelAccelerator.jl. Thanks to everyone at JuliaCon for being a great audience for this talk!

Everything in the latter twenty minutes of my talk is already pretty well covered in my blog post from March that introduced the ParallelAccelerator package, so in this post, I’ll focus on just the first ten minutes or so.

Do ‘all Java type checkers have bugs’?

A few days ago, my friend Stephen Tu pointed me in the direction of “Java Generics are Turing Complete”, a “short note” that Radu Grigore recently posted on arXiv. In it, Grigore shows that in Java, subtyping is undecidable (his “Theorem 1”) and that therefore, type checking is undecidable. He then remarks:

For Java, Theorem 1 implies that there cannot exist a formally verified type checker: All Java type checkers have bugs.

Stephen wanted to know what exactly the claim of “all Java type checkers have bugs” meant. To understand what this means, let’s take a closer look at Grigore’s result.

What even is OpenStack?

A few days ago, I needed to learn what OpenStack is. Here’s what I’ve learned so far.

OpenStack is a collection of open-source “cloud infrastructure” services. One way to think of it is as an alternative to Amazon Web Services for those who want to operate their own data center instead of paying Amazon.1 Several of the OpenStack services are roughly analogous to Amazon services. For instance, OpenStack Nova is an alternative to Amazon EC2; OpenStack Swift is an alternative to Amazon S3; and OpenStack Cinder is an alternative to Amazon EBS. The OpenStack people publish a long list of organizations that use OpenStack in various ways.

Help the !!Con 2016 attendees eat breakfast

Update (May 5, 2016): Thanks to everyone who’s offered to chip in and help !!Con out financially! There’s now an easy way to do so as an individual: bangbangcon.lfranchi.com (hosted by my fellow !!Con organizer Leo Franchi). Read the rest of this post to learn about our financial situation and why I’m asking for help.

Update (May 11, 2016): You people are amazing! At the last minute, !!Con got a sponsorship from Stride, plus over $1600 in contributions from individuals. With their help, we were able to serve bagels, fruit, and coffee on both days of the conference! Thank you so much!


Regular readers of this blog may know that I’m one of the organizers of !!Con (“bang bang con”), an eclectic and inclusive conference of ten-minute talks about the joy, excitement, and surprise of programming.

2016 marks the third year of !!Con, which is held annually in New York City. This year, our program features talks on the usual bewilderingly broad range of topics: lossy text compression, interplanetary spacecraft flight software, storing your data in kernel space, and more. I can’t wait!