[jprzybyl]

> POSIX was designed to be used on systems with comparable resources to what many embedded processors now have.

But not comparable environments. Most IOT environments are very small parts of very big systems, and POSIX defines a system with a teletype and a line editor.

I seriously doubt the value of the existing codebase. Saying code made for a server (like most existing unix code!) is fine for IOT feels wrong, and not just because IOT devices have kilobytes of memory and servers can have gigabytes/terabytes.

I don't think that a universal OS can work well when we know that universal programming languages, data transfer protocols, and everything else didn't. Imagine if we were still doing everything in PL/I. We recognize now that different programming tasks need different programming environments, but we still don't think that different programs need different program environments. It's just strange to me.

[kevin_thibedeau]

> Saying code made for a server (like most existing unix code!) is fine for IOT feels wrong,

There was a time when people ran Linux/SunOS/Ultrix/etc. with tiny amounts of RAM and swap. It's not unusual for an embedded device to have 8, 16, 32 MiB, or more RAM available. Many traditional *nix programs can run unchanged on such hardware.

[cmrdporcupine]

I think the parent's comment was more along the lines of: just because an embedded device _can_ run a Unix doesn't mean it should have to adopt the semantics and history of the *Unix environment that POSIX mandates. In particular the model of TTYs, filesystems, Unix-style file/IO, Unix-style virtual memory / mmap, etc. It's not that this stuff is expensive on modern embedded systems (which as pointed out often have the hardware capacity of high end systems from 20 years ago), it's that these capabilities are either not needed, or impose a conceptual model of what a computer and operating system have to be that don't match up to what the machine is designed for.