[Coco] OS9 vs Flex

[John Kent]

On 2/01/2012 9:56 AM, john dumas wrote:
> On 12/31/2011 6:10 PM, John Kent wrote:
>>
>> There is interrupt driven printer spooling. The disk drivers set the 
>> interrupt flag so that the interrupts won't interrupt the disk 
>> read/write sector operations.
> Righto.
> Interrupts can be requested from several sources.
>
> Still a single user system, though..........Like original DOS,
> CP/M etc which had interrupt capability....And still Single User.
>
> Still and all, I did like it - in it's time and place.
> Until the downside of large disks and flat file structure
> continued to bite me in the tailpipe.
> That problem was later addressed by programs like
> "heir", but by that time I had moved on........
>
> Memories.........sigh
>
> cheers,
> johnd

The point of designing the FPGA 6809 was to learn a little about CPU 
architecture. You can still demonstrate principle of multiprocessing and 
caching with a simple 8 bit CPU. I'm not sure if it is possible to turn 
the 6809 design into a Harvard architecture where it can be accessing 
data at the same time as it is fetching instruction opcodes out of cache.

John.

-- 
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