Thank you for the explanation, Gorgonops.
Is that burst mode which fills the cache a programming choice? In other words, is that an instruction which the programmer chooses to use or not use? Or is it something the CPU does automatically, when the cache needs filling -- presumably with some provision for memory systems slower than 35ns to signal that the CPU will just have to wait for the next data element.
I ask, because the interesting question is whether the burst mode is ever used by the 68030 in the SE/30. If it tries to use the burst mode to fill the cache, and the SE/30's bus responds with some kind of signal that it's going to get things slower than that, then that is something we could work with.
But if the burst mode just isn't in the code at all, then using it would require rewriting the whole Mac OS and possibly the applications as well. And that's really not very practical.
In the former case, it might be possible to install a fast memory system (FPGA to DDR2 DRAM at 333 MHz) in the PDS slot and then somehow (PMMU?) map the RAM accesses to address space decoded in the PDS slot by the FPGA.
Re: SCSI Manager. I don't know how useful this is, but in case it has some use, I think, start the thread here:
http://68kmla.org/forums/viewtopic.php?p=61401#p61401
Is that burst mode which fills the cache a programming choice? In other words, is that an instruction which the programmer chooses to use or not use? Or is it something the CPU does automatically, when the cache needs filling -- presumably with some provision for memory systems slower than 35ns to signal that the CPU will just have to wait for the next data element.
I ask, because the interesting question is whether the burst mode is ever used by the 68030 in the SE/30. If it tries to use the burst mode to fill the cache, and the SE/30's bus responds with some kind of signal that it's going to get things slower than that, then that is something we could work with.
But if the burst mode just isn't in the code at all, then using it would require rewriting the whole Mac OS and possibly the applications as well. And that's really not very practical.
In the former case, it might be possible to install a fast memory system (FPGA to DDR2 DRAM at 333 MHz) in the PDS slot and then somehow (PMMU?) map the RAM accesses to address space decoded in the PDS slot by the FPGA.
Re: SCSI Manager. I don't know how useful this is, but in case it has some use, I think, start the thread here:
http://68kmla.org/forums/viewtopic.php?p=61401#p61401