On 18-Oct-2007, at 09:09, Tony Finch wrote:
Er, yeah, sorry. It's quite hard to find an embedded OS that doesn't
pretend to be unix.
RT-11, RTE-IV, RSX-11, RMX-86, ...?
Three of those are dead minicomputer OSs so don't really count as
embedded
in my books.
RT-11 and RSX-11 are still maintained and supported by Mentec, on
real and emulated hardware.
And pretty much any "pre-UNIX" embedded OS is going to be mini-based,
given the timeframe.
RMX is windows-oriented but seems to have its own APIs.
RMX has been retargeted as a hosted system, but it was definitely a
complete standalone embedded os in the '80s and early '90s.
An
interesting beast - there aren't many OSs that use segment
registers (for
more than just setting up the 32 bit flat memory model) and multiple
security rings on the x86.
Well, it was written by Intel. :)
One of the things that really made me a hero at ABB was working on a
project to automate converting PL/M-86 for RMX into maintainable (if
ugly) portable C code. The hardest part wasn't the segment registers,
surprisingly, it was figuring out what code using "AND" and "OR"
needed to be "&" and "|" and which needed to be "&&" and "||". I
don't recall if it was Randy or Walker who came up with the
solution... we converted BOTH to the same thing and then ran
flexelint over it and changed the ones that it complained about.
