Who cares about posix? It's not the 2000's anymore. Solaris is dead. HP-UX is dead. Were you worried that someday you might have to port your shell script to AIX?
GNU and Linux won. The only BSD environment is macOS, and if you put GNU on macOS, then the only thing I can think of that's worth a mention is alpine and busybox containers, but at that point it feels like we're just grasping at straws.
There are more computers on this planet than just plain desktop.
Most of them are servers, mainframes and embedded devices running some form of UNIX based OS.
If you prefer I can rename it to nix, as I wasn't thinking about POSIX certification.
BSD, Minix (running on your Intel chip), Aix, HP-UX, POSIX layers in IBM and Unisys mainframes, RTOS, NuttX, QNX, and many other POSIX based OSes for embedded deployment.
There are the embedded and mainframe OSes, but I guess they might be considered niche.
Not so niche are iOS and Android, which aren't fully POSIX compliant.
Then being POSIX compliant is only half of the story, because each OS tends to be certified to specific versions and there is room for implementation specific behaviours.
For example, Aix used to have Windows like model for dynamic libraries. OS X and its derivatives have Frameworks and so on.
Finally POSIX only applications are constrained to CLI and daemons only, as everything else falls outside POSIX.
This article is biased towards desktop environments, but misses embedded.
Lots of RTOSes are POSIX compliant for things like Pthreds and file systems. Off the top of my head, VxWorks, RTEMS, INTEGRITY, and QNX all have POSIX compatability.
Except AFAIK there are zero features in POSIX that came from GNU/Linux.
Now, if anything I do agree that UNIX is stuck on the past by not having any standard workstation environment or adoption of modern kernel architectures.
Also CDE is not what one would expect from a 2015 workstation.
the posix personality still exists - it's called SUA; the Subsystem for UNIX Applications. the guys at interop systems have made a really nice ports-esque system for it so it's easy to get up and running with the usual pile of apps.
To be fair, software written against Unix-flavored POSIX runs on almost every commercially supported operating system out there, from Linux and QNX, macOS and all the way to z/OS, which is a certified UNIX operating system (incredibly).
The only significantly used OS that’s not there is Windows. Also, IBMi, Unisys’s MCP and Atos’s GCOS and GECOS (surprisingly still supported). And OpenVMS too.
It's revelant on servers, workstations, embedded systems, and supercomputers.
So, basically everywhere.
The thing is: you're unlikely to be programming directly on top of the POSIX API unless you're doing something comparatively low level to the average programming that is done in industry today.
Embedded is an area where applications are often written right on top of libc and POSIX interfaces. Even many RTOS which are not fully POSIX compliant borrow a lot of ideas from UNIX.
UNIX/POSIX clones and embedded still demand C for most workloads, so that is going to be quite hard to ever change.
There is some hope for embedded, when enough developers are gone, however for UNIX/POSIX it is impossible given the symbiotic nature of both, only when we get rid of UNIX clones.
The last POSIX came out in 2017, and it's a constantly evolving standard. It's also widely supported and Linux isn't even the most standards compliant.
I was including Linux there, as it follows a standard UNIX architecture.
There is a big difference in having POSIX support and being a UNIX.
Windows, IBM i, IBM z/OS, Unysis MCA ClearPath, Green Hills INTEGRITY OS, Genode and many other OSes have POSIX support, yet their architectures have nothing to do with UNIX.
My feeling is POSIX is still pretty important in the safety critical embedded world. Green Hills Integrity, VxWorks, QNX, RTEMS all have some market presence and aim for POSIX compliance.
Additionally, embedded also has plenty of POSIX like OSes that arent' Linux based.
reply