[Coco] Re: Re: Questions about the 502 controller vs the Disto SCII

[Mike Pepe]

Warren Hoslet wrote:
>>> I did have no halt setup when I had my multipak and B&B harddrive  
>>> controller
>>> setup. Mr. Gault helped me with that. :)
>>> How would it help playing Kings Quest? I saw its benefits while
>>> multitasking, but if your just playing a game how would it help?
>>    Keyboard type ahead works even when the game is loading the next  
>> picture/map, etc. With a halting controller, all key presses during 
>> drive  access are lost.
> 
> How is ho-halt implemented by the SCII? Does it perform disk I/O from a 
> buffer on the controller card without requiring the 6809 to handle the 
> timing-critical task. If the 6809 has to do the work I would think that 
> it would still have to mask interrupts which would prevent keyboard 
> type-ahead. Since I have no technical knowledge of the SCII, I'm just 
> speculating.
> 
> - Warren
> 

Yes, it has a built in 8k sram memory chip. (only 256 bytes of which are 
really ever used) The read-in/out functions are largely the same as the 
RAMdisk design Tony DiStefano published in Rainbow.