Re: A86: Re: New operating system...
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Re: A86: Re: New operating system...
>That IS a good idea, and I have _thought_ about it. But since the OS
is
>contained in ROM, how do you propose to put a new OS on the calculator?
Well sure the OS is in rom, but it also eats up a lot of space in ram
with system variables, VAT, and whatever else that it does, that I as a
programmer simply am tired of having to skirt around. Particularly,
this last 16Kbyte block that is located permanently at $c000.. the
first ~5K is used by the system right? I mean I don't know all the
details, but there must be some reason that the TI-os loads asm programs
at $d748. so I'm assuming $c000-$d748 is used by the system.
Anyway, you write a "bootloader" that loads the kernal into ram
somewhere and this becomes the new operating system. The prorgam never
gives control back to the rom, so it therefor uses the ram how it wants
to. Now I am still not sure how I want this new OS to use the ram...
but I had got an idea yesterday:
Instead of having a "ram-disk" or variable-disk or whatever you want to
call it that stors "programs" and "data" why don't we create an
operating system that simply has one type of memory. This memory will
contain "segments" that can either be data or program. If it is program
then it has the ability to be "run". So instead of "loading" programs
to be run, we can simply ahve our operating system load the appropriate
"pages" of ram and then call this segment. Every time you load a
program you are making an extra "unecessary" copy of it. If we want to
run multiple programs on a 128K platform, this program copying is
wastefull. And under this paradigm, running another program would be as
simple as adding this segment's address to the task-schedualer.
Now this paredigm might be at first seem to wild and different to even
think about. But give it some thought. Now I know that there are
several things that must be done in preperation to even think about
making such a system work. Some subtle, and some pure out blatent, but
I think you will find that these preperotory task are all "doable" and
not only that. The bulk of this stuff can be done by the OS without the
programmer having to worry about it.
Later,
David E. West
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