> 
> At 9:47 AM 9/10/97, Colin Wood wrote:
> >Rodney M. Hopkins wrote:
> >I'm pretty sure that SCSI Manager 4.3 is software, and I think that it's
> >been in the system file since like 7.5.0 or so.
> >
> 
> Yes, it's MacOS software and therefore irrelevant to MacBSD.  Also it only
> supports asynchronous transfer on newer DMA machines like the 650 and up.
> No benefit at all on an SE/30, even under MacOS.  It didn't even support
> the DMA on the IIfx, although it should have.

As far as I know, only the Q660 & Q840 actually supported DMA. The IIfx
didn't, nor did the Q650's & so on.

The IIfx had I/O Processors, so that the CPU would just have to do a
memory move to feed data to the IOP. It's not DMA in that the CPU has to
move, the data, but it's a helluva lot faster than waiting on the I/O.

I think the other thing that SCSI Manager 4.3 did was to support running
the SCSI commands as asynchronous events. That support would work
even w/o DMA. (and break programs... :-)

Take care,

Bill