Floating point arithmetic is a popularly esoteric subject in computer science. It is safe to say that every software engineer has heard of floating point numbers. Many have even used them at some point. Few would claim to actually understand them to a reasonable extent and significantly fewer would claim to know all of the corner cases. That last category of engineer is probably mythical or, at best, optimistic. I have dealt with floating-point related issues in the GNU C Library in the past, but I won’t claim to be an expert at it. I definitely did not expect to learn about the existence of a new kind of number, as I did a couple of months ago.
Continue reading Mostly harmless: An account of pseudo-normal floating point numbers
Red Hat’s single sign-on (SSO) technology, based on the Keycloak open source project, is Red Hat’s solution for securing web applications and RESTful web services. The goal of Red Hat’s single sign-on technology is to make security simple, so that it is easy for application developers to secure the apps and services they have deployed in their organization.
Continue reading Using Red Hat’s single sign-on technology with external databases, Part 1: Install and configure SSO with MariaDB
Building a production-ready application has a ton of moving parts. Most of the time, developers create a new project using some sort of tool, like Maven archetypes, and then go from tutorial to tutorial piecing together everything that is needed for their application. This article tries to bring all the parts together and provide a single full reference to the work that needs to be done for a Quarkus application. You can find all the examples from this article on GitHub.
Continue reading Build an API using Quarkus from the ground up
I think of machine learning as tools and technologies that help us find meaning in data. In this article, we’ll look at how understanding data helps us build better models.
Continue reading The machine learning life cycle, Part 1: Methods for understanding data
Technology and infrastructure generate an enormous amount of data on a day-to-day basis. Building knowledge out of this data in various real-world domains can be a big challenge. This article describes how to derive concise and precise knowledge from data and use it to track vulnerabilities in the software stack. It presents challenges related to package security and vulnerability and how they can be addressed using a knowledge graph. After reading this article, you’ll understand the concept of the knowledge graph and how you can apply it to your domain.
Continue reading Use knowledge graphs to discover open source package vulnerabilities
This is the second article of a two-part series in which I describe the automated testing infrastructure that I am developing for the SystemTap project. The first article, “Automating the testing process for SystemTap, Part 1: Test automation with libvirt and Buildbot,” described my solution for managing test machines and for producing SystemTap test results. This follow-up article continues by describing Bunsen, the toolkit I developed for storing and analyzing test results.
Continue reading Automating the testing process for SystemTap, Part 2: Test result analysis with Bunsen
C++ standardization was dramatically different in 2020 from earlier years. The business of the International Organization for Standardization (ISO) committee all took place virtually, much like everything else during this pandemic. This article summarizes the C++ standardization proposals before the Core and Evolution Working Groups last year.
Continue reading Report from the virtual ISO C++ meetings in 2020 (core language)
For a multitude of reasons, developers usually compile the project they are working on with only one compiler. On Red Hat Enterprise Linux 8, the system compiler for C and C++ is GNU Compiler Collection (GCC) 8, and newer versions are available through the GCC toolset.
Continue reading Use multiple compilers to build better projects
I recently wrote a few automated database-populating scripts. Specifically, I am running Microsoft SQL Server in a container in a Kubernetes cluster—okay, it’s Red Hat OpenShift, but it’s still Kubernetes. It was all fun and games until I started mixing Windows and Linux; I was developing on my Windows machine, but obviously the container is running Linux. That’s when I got the gem of an error shown in Figure 1. Well, not so much an error as errant output.
Figure 1: Errant output from an SQL statement.
Continue reading “Why Windows and Linux line endings don’t line up (and how to fix it)”
Over the past year, I have been implementing an automated infrastructure to test the SystemTap project and to collect and analyze the test results. SystemTap is a scripting language for creating instrumentation to observe a live running Linux kernel and user-space applications. The SystemTap language translator produces Linux kernel modules. These modules depend on internal details of the Linux kernel that vary significantly between different versions of Linux.
Continue reading Automating the testing process for SystemTap, Part 1: Test automation with libvirt and Buildbot