Re: Idea: Multitasking graphical OS for the GS

[Eric Rucker <bhtooefr@gmail.com>]

On Jan 1, 7:07 pm, Michael Black <et...@ncf.ca> wrote:
> On Thu, 1 Jan 2009, Eric Rucker wrote:
> > I've been thinking about stuff, and got to thinking... it'd be
> > interesting if there were a semi-modern, multitasking, graphical OS
> > for the IIGS - not necessarily backwards compatible with GS/OS. (The
> > semi-modern bit means... The Manager on GS/OS does NOT qualify. ;))
>
> > Anyway, I'm thinking that starting from scratch with the OS might just
> > be the best bet - unlike GNO/ME, which uses GS/OS for a lot of stuff.
>
> > That doesn't mean that I'd be shunning all of the built-in IIGS stuff
> > - the Toolbox would come in handy for the GUI. (FWIW, I think I know
> > how I'd handle the toolbox in a multitasking environment - simply
> > create a "virtual toolbox" that apps for this OS would make calls to,
> > and then pass those calls onto the real toolbox. As far as the real
> > toolbox is concerned, it's just one app with a bunch of windows, that
> > wants to change its menus. A lot. ;))
>
> > But, I suspect a modern multitasking kernel for all of this would be
> > more efficient. I know, there's no MMU. That never stopped Minix or
> > ELKS...
>
> There was multitasking on 8bit computers.  I seem to recall Microware
> had it on the 6800, and there might have even been an article about
> a multitasking monitor or kernel in Kilobaud (I can sort of picture it).
>
> Then of course, Microware did come out with OS-9 for the 6809, which
> admittedly is fancier than the 6502.
>
> The concept of multitasking was fairly easy, there was a book about the
> 68000 that had a monitor or kernel that multitasked.  Dr. Dobbs probably
> ran some stuff on that too.
>
> It just really depends on what you want.  In the old days, the operating
> systems were pretty simple, indeed some times it was just a matter of
> running two programs that stood alone, the multitasking just being a
> switch between the two.  An obvious example was a print spooler, sharing
> the CPU to send the characters to the printer in the background.  Those
> were described back then too.
>
> Even Unix was simple to begin with, the PDP-11 that it was originally
> run on did not have memory management.  Of course, Unix was far more
> than the kernel, it was the utilities and the applications that made
> it useful, not so much the kernel.
>
> Minix of course was designed to teach about operating systems, so one
> might more properly be thinking about Minix in what it can teach about
> the concepts, rather than a source to
>
> You really have to decide what you are trying to do.  Do some background
> tasking, or a full blown OS?  A completely new system that runs on
> the 65816 (or even 6502?), or something that does multitasking but
> allows existing programs to run on top of it?  That last is likely
> the most useful, since then you have things to actually do with
> this OS, but is also likely the hardest since one has existing
> specifications to meet.
>
>    Michael
>
> > Speaking of Minix, I'm almost wondering if some heavily-modified Minix
> > derived kernel would do the trick. The stock Minix memory manager can
> > only handle 64k of code and 64k of data per application on a 16-bit
> > CPU (I think that's a word-length restriction,) but maybe that could
> > be fixed? Binary compatibility with Minix would be unnecessary, so...
> > And, IIRC, it has installable file systems, and stuff like that, which
> > would work nicely in the IIGS ecosystem.
>
> > But, Minix is just an idea, and isn't necessarily the best one. It's
> > just something to think about.
>
> > Is anyone interested in such an OS? Either using it, developing it, or
> > developing for it?

I'm aiming for a completely new full-blown OS. Maybe it can extend
that "virtual toolbox" idea I had for making the GUI work to
everything that the IIGS uses now, and maybe even just using a couple
elements of Minix (the kernel and some of the driver architecture, for
instance) or another OS to provide a kernel for this OS. That would
facilitate porting of toolbox applications, as you could just
recompile to the new target.

I've obtained a copy of the second edition of Operating Systems:
Design and Implementation, so I can study this. I think my first goal
will be to try to get a barebones Minix 2.0 setup running on a GS
emulator, and work from there, figuring out what's needed and what's
not needed.