Re: DMA 4 meg v. 8 meg

[dog_cow@macgui.com (D Finnigan)]

KP wrote:
> I have a 4 meg RAM card in the memory slot of my ROM 03 IIgs.  I have
> often heard that only the first 4 megs of expansion-card RAM is DMA-
> compatible.  Can somebody explain what DMA actually is?

DMA means Direct Memory Access and it's a way to alter the contents of
memory without involving the CPU. In most cases, this makes the transfer
faster.

> 
> Does this mean that the second 4 meg of expansion card RAM is useful
> only as a RAM disk, and not as memory for programs to access, in order
> to store long documents that the user is editing, graphics being
> opened from disk, sounds being edited, HyperStudio stacks, etc.?
>

No, that's not true. It just means that direct memory access can't be used
in that range.

-- 
]DF$
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