Again ISA DMA question

 Hello, all!

 In a source code or AROS operating system (http://www.aros.org) i found this comment:

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    The older PReP machines have the DMA area limited to first 16MB of system
    memory. Therefore it is reasonable, to place the kernel at the end of DMA
    RAM. Both areas may be then easily separated.
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 Does this mean that Linux has an option to limit DMA memory space to first 16 MB? PReP machines are fully supported i guess. Or not fully?

 Kind regards