English Amiga Board - View Single Post - Insights on how accelerator cards work on Amigas

jman · 26 April 2011, 14:10

Hello eveyone,

I'd like to better understand how these cards generally work on the Amiga platform. I probably have a lot of of wrong ideas in my head, so I'd appreciate someone who can shed some light.
I tried to have a random look at some devices on amiga-hardware.com but descriptions do not asnwer my questions.

So, if I'm not wrong, these are not "daughter" boards as it was a 3DFX Voodoo, they do not accelerate just some specific task: they are plugged tipically to an expansion slot and *replace* completely the main CPU. They do have they own RAM, possibly a FPU chip. Latest Cybervision also had a dedicated GPU unit, though.

Q1) Does the stock CPU and its bus/dma is excluded and replaced by the new one? Or is it still used for "light" tasks such as input interrupt, device access and alike? In this case does the stock CPU (and its bus) is itself a bottleneck?
Q2) How much of the original host system is not excluded? Maybe the custom OCS/ECS/AGA chipset?
Q3) Is the expansion slot a bottleneck for these external cards?

Well, I think that's all I need to know for the moment :-)

Thank you!

26 April 2011, 14:10	#1
jman Registered User Join Date: Nov 2010 Location: . Posts: 359	Insights on how accelerator cards work on Amigas Hello eveyone, I'd like to better understand how these cards generally work on the Amiga platform. I probably have a lot of of wrong ideas in my head, so I'd appreciate someone who can shed some light. I tried to have a random look at some devices on amiga-hardware.com but descriptions do not asnwer my questions. So, if I'm not wrong, these are not "daughter" boards as it was a 3DFX Voodoo, they do not accelerate just some specific task: they are plugged tipically to an expansion slot and replace completely the main CPU. They do have they own RAM, possibly a FPU chip. Latest Cybervision also had a dedicated GPU unit, though. Q1) Does the stock CPU and its bus/dma is excluded and replaced by the new one? Or is it still used for "light" tasks such as input interrupt, device access and alike? In this case does the stock CPU (and its bus) is itself a bottleneck? Q2) How much of the original host system is not excluded? Maybe the custom OCS/ECS/AGA chipset? Q3) Is the expansion slot a bottleneck for these external cards? Well, I think that's all I need to know for the moment :-) Thank you!