MacRelix is a Unix-like environment that runs in classic Mac OS.

MacRelix natively supports classic 68K and PPC Mac OS, as well as Mac OS X on PPC via Carbon.

↫ MacRelix website

The creator of MacRelix, Josh Juran, published an article in 2019 detailing the origins of the project. As a Mac OS developer, he was so unhappy with both CodeWarrior and Apple’s Macintosh Programmer’s Workshop (MPW), that he set out to create what would become MacRelix in 1999. Reading through the limitations and roadblocks he experienced with CodeWarrior and MPW, it’s not hard to see why he got frustrated – CodeWarrior’s targets were apparently a mess and a half to deal with.

Then came target multiplication. Whereas the initial CodeWarrior developer releases shipped with each combination of language (C and Pascal) and architecture (68K and PPC) supported in a separate application, a later version of the IDE unified these, allowing the developer to have a single project file per project. To allow the same project to be built for both 68K and PPC architectures, the project data model included targets: One target would compile for 68K and link against 68K libraries, another would do the same for PPC. Targets could also be used to select an optimized build versus one for debugging. Combining both dichotomies yields four targets: 68K debug, 68K optimized, PPC debug, and PPC optimized. Then if your project involves multiple executables, like a code resource or shared library in addition to an application, you now have eight targets. Or, if you support one of, say, 68020 optimization, profiling, or a third executable, make that twelve. Or, for all of them, twenty-seven.

↫ Josh Juran

Changing an option in your application required you to change it in every single target, too, which I can easily see is incredibly frustrating. MPW, for its part, was a massive improvement, he argues, but while it was clearly inspired by UNIX, it didn’t seem to actually implement any of the features and characteristics of UNIX.

However, very much unlike Unix, the MPW Shell had only a single thread of execution — only one program could be running at once. Not only that, but there was no way for MPW’s compiled plugins (called tools) to invoke other tools or scripts — not even via system() (which blocks the calling program until the called program exits). Therefore, Make couldn’t actually do anything, but only printed out the commands for the user to run manually. You could code in Perl instead of the built-in language, but then your scripts couldn’t run other programs — only MPW shell scripts could do that.

↫ Josh Juran

The limitations Juran was experiencing with these two tools pushed him to create his own solution, which went well beyond what MPW offered, even in 2019 when this article was published.

Nowadays, MacRelix has pipes, signals, system calls, TCP sockets, and more. It works on both 68K and PowerPC Mac systems and builds as Carbon to run natively in OS X. It can be used on any Mac OS version from System 7 to Mac OS X 10.6 “Snow Leopard” (after which Apple removed the Rosetta PowerPC emulator). I haven’t implemented fork() yet, but I know how to do it. In addition to a Unix-like file system interface (which even handles long names by storing them in Desktop database comment fields)), MacRelix has a /proc filesystem (with human readable stack crawls) and also maps various parts of Mac OS (e.g. the ROM image in /sys/mac/rom).

↫ Josh Juran

I had never heard of MacRelix, but it seems like an amazing tool Juran put a lot of thought, effort, and love into. Sadly, with the number of PowerPC Mac OS X users being vanishingly small, and the number of classic Mac OS users even smaller so, the future of MacRelix seems uncertain. I wonder what parts of it can be salvaged and upgraded to work on ARM macOS or even Intel macOS, because I think the ideas and concepts are incredibly cool.

A related project by Juran is something called FORGE, a portable windowing API that used a virtual file system, meaning that instead of using functions as objects, it uses files. Juran mentions the example of a window title – which is a file, and if you want to change the title of that window you just change the file, which will be instantly reflected in the GUI. Here’s a Hello World example:

cd $FORGE/gui/port/hello        # select a window port named "hello"
exec 9> lock                    # exclusively retain the port for our use
ln new/caption view             # add a caption as the window’s view
echo Hello world > v/text       # set the caption text
touch window                    # create the window

Even though I’m not a programmer, this little tidbit of code makes perfect sense to me, and I understood it instantly. Of course, anything more complex will quickly leave my wheelhouse, but intuitively, I really like this. FORGE exists as a prototype inside MacRelix, so you can play with this concept while using MacRelix.

Back when I was working on my article about PA-RISC, HP-UX, and UNIX workstations in general, I made extensive use of OpenPA, Paul Weissmann’s invaluable and incredibly detailed resource about HP’s workstation efforts, HP-UX, and tons of related projects and products. Weissmann’s been doing some serious digging, and has unearthed details about a number of essentially forgotten operating system efforts.

First, it turns out HP was porting Windows NT to PA-RISC in the early ’90s.

Several magazine sources and USEnet posts around 1993 point to HP pursuing a PA-RISC port to NT, modified the PA-RISC architecture for bi-endianess and even conducted a back-room presention at the ’94 Comdex conference of a (modified HP 712?) PA-7100LC workstation running Windows NT. Mentions of NT on PA-RISC continued in 1994 with some customer interest but ended around 1995.

↫ Paul Weissmann at OpenPA

The port eventually fizzled out due to a lack of interest from both customers and application developers, and HP realised its time was better spent on the future of x86, Intel’s Itanium, instead. HP also planned to work together with Novell to port NetWare to PA-RISC, but the work took longer than expected and it, too, was cancelled.

The most recent secretive effort was the port of HP-UX to x86, an endeavour that took place during the final days of the UNIX workstation market.

Parts of the conversation in these documents mention a successful boot of HP-UX on x86 in December of 2009, with porting efforts projected to cost 100M+ between 2010 and 2016. The plan was for mission-critical x86 systems (ProLiant DL980 and Superdome with x86) and first releases projected in 2011 (developer) and 2012 (Superdome and Linux ABI).

↫ Paul Weissmann at OpenPA

I’m especially curious about that last one, as porting HP-UX to x86 seems like a massive effort during a time where it was already obvious Linux had completely obliterated the traditional UNIX market. It really feels like the last death saving throws of a platform everybody already knew wasn’t going to make it.