Last week we reported that the FreeBSD team was working on making builds of the FreeBSD operating system and its ports reproducible. Another project which is trying to make their builds consistent and reproducible is NetBSD. A blog post on the project's site covers many of the steps the NetBSD developers had to take to create reproducible builds. "I have been working on and off for almost a year trying to get reproducible builds on NetBSD. I did not think at the time it would take as long or be so difficult, so I did not keep a log of all the changes I needed to make. I was also not the only one working on this. Other NetBSD developers have been making improvements for the past six years. I would like to acknowledge the NetBSD build system (aka build.sh) which is a fully portable cross-build system. This build system has given us a head-start in the reproducible builds work. I would also like to acknowledge the work done by the Debian folks who have provided a platform to run, test and analyze reproducible builds. Special mention to the "diffoscope" tool that gives an excellent overview of what's different between binary files, by finding out what they are (and if they are containers what they contain) and then running the appropriate formatter and diff program to show what's different for each file." NetBSD builds are now reproducible on amd64 and sparc64 architectures with work on-going for other hardware platforms.