Questions on how the ND works

Started by barcher174, December 13, 2013, 04:56:19 am

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barcher174

Hi all,

I'm curious about some things I've read on the dimension. From my understanding the card runs it's own stripped down kernel. Is this held in ROM on the card, or does it get loaded from disk? Is there anyway to access the card OS?

Thanks,

Brian

cubist

Quote from: "barcher174"
I'm curious about some things I've read on the dimension. From my understanding the card runs it's own stripped down kernel. Is this held in ROM on the card, or does it get loaded from disk? Is there anyway to access the card OS?

In the early 90's, i860 designs were popular and the pattern was something like the following.   All code initially resides on the system disk for ease and simplicity of updating.  A very small rtos (think freertos) is loaded onto the i860 along with a core set of hardware/video support functions.  The i860/rtos combination supports demand paging using host physical memory as backing store.  Non-pageable code on the i860 manages this in cooperation with host OS driver support.  Additional firmware support manages power-on functions like initialization and boot console.  

In the case of NeXT's version of this recipe, the rumor is that very little real acceleration was implemented.  How true that is, I don't know...

gtnicol

There is certainly a kernel in there, but I think the only real access (other than via some communication on the NeXT bus) is via postscript.

cuby

A few details on the interaction of the Dimension with the rest of the system can be found at http://support.apple.com/kb/TA45926?viewlocale=en_US&locale=en_US