[Coco] OS9 vs Flex

[john dumas]

On 1/2/2012 3:09 AM, John Kent wrote:
>
>
> 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.
>
Interestingly, the 6804 was a Harvard architecture pretending to be a 
6805 (Von Neumann) and doing a subset of 6805 instructions.
Way too small and dumb to have a cache though!!

Wouldn't need an FPGA /CPLD to recreate an '04............maybe a few 
TTL gates............HA!


And speaking of multiprocessing with simple machines:
While at TI in the 70s, we were making single chip 4-bit calculators and I
got the idea of how to slave a couple together to "multiprocess" (sorta).
Being young and naive, it became my first patent application.
Denied, of course. Not a new an idea as I had though.
Silly me!

Still kinda it's neat to make simple machines a tad "smarter"........
I like fooling around with ideas like that, even if impractical.

Cheers & a Happy New Year,
johnd

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