The POSIX layer was added the year before Elop came to Nokia, Symbian with Qt and PIPS was starting to look rather good, and Symbian Belle on an Nokia C7 was rather nice.
Not really, no. GEOS on top of a ROM DOS did something similar, albeit in a much more primitive sort of way.
GEOS was the OS of the HP OmniGo 100, Omnigo 700, and original Communicator 9000, IIRC. Symbian was the OS of the later Communicators, like the E90 I owned.
GEOS is built on DOS: single tasking, no memory management, text mode, took 640 kB of RAM with apps.
Symbian is EPOC32, EPOC version 5. EPOC 16, its forerunner, ran on an 8086, and in 256kB of RAM it had a full GUI, with multitasking graphical apps, and a dynamic RAMdisk, and it was stable enough to run for months, on 2 AA batteries, with that RAMdisk as the sole storage for all those multitasking apps.
EPOC is to DOS as a Tesla Roadster to a Model T Ford.
Saying that, I am watching GEOS with interest, and I have suggested to the FreeDOS folks that they should incorporate it. Currently the most mature functional FreeDOS GUI is FreeGEM but Geos does much much more.
https://github.com/SymbianSource
Please, please, someone revive this. It was a pleasure to use.
Junk as much as possible of the idiosyncrasies and slap a standard GUI toolkit on top, like Qt or Gtk or something.
It already has a POSIX layer:
https://en.wikipedia.org/wiki/P.I.P.S.
It's as if BeOS had been open sourced and nobody noticed.
It's more complete and more functional than Genode, for instance. It runs on bare metal, unlike Serenity OS.