[Coco] CoCo OS-9, a short simple explanation

[James Jones]

An operating system is software that implements an abstraction of the
hardware of a computer. Well-chosen abstractions let you write code that
isn't tied to specific hardware (in theory, you could even have "language"
codes for modules that indicate the emulator to run them under--BASIC09
I-code defines a VM just as Java byte code defines the JVM, so there's
certainly precedent; it just takes serious resources to emulate an actual
CPU. The 6809 and 6309 couldn't pull it off).

One aspect of that abstraction is how much choice the OS designer gives the
user. Most of the "DOS"es for the CoCo just add various disk-related
commands to the Color BASIC interpreter. OS-9 is influenced by Unix, which
gives you a choice of what to run when the system comes up (or what to run
when you log in if you are set up to run tsmon). The mantra is one from X
Windows: "mechanism, not policy", i.e. we give you a way to do things, we
don't impose on you. You could write your own shell and use it instead of
the one that comes with OS-9; as Barry says, OS-9 isn't a language. Apple
knows what windowing interface you should have, and by golly, you'll like
it. Aside from hacks like Stardock's Object Desktop, Windows is the same
way. Unix/Linux doesn't impose; There are dozens of windowing
environments/window managers.

James

On Tue, May 17, 2016 at 10:04 AM, Brett Gordon <beretta42 at gmail.com> wrote:

> 1+
>
> Brett M Gordon
>
> On May 17, 2016 10:21 AM, "Aaron Wolfe" <aawolfe at gmail.com> wrote:
> >  Doing asm
> > work on OS9 is similar(ish) to doing C work on unix.. it just feels
> right.
>
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