#2091 in 4000?
>You want 7.xx 2091 roms.
Which I got. and…it works badly. My external SCSI drive is only
transferring at a rate of about 70K/second, and sucks the entire CPU doing
it.
I dug around in some old experiments and put some 256×4 RAM into it (1M),
but this did not help.
It occurs to me that either the max transfer or mask is wrong.
The max transfer defaulted to 7ffffffe and maxtransfer default to ffffff.
I tried changing max transfer to fffffff, with no effect, and ffffffff
with crashes (oops!). It occurs to me that perhaps even with the 7.00
roms, the thing is still DMA'ing into CHIP ram. I wonder if there's a way
to use the mask to force the DMA to do into the 1M of ram I put on the
2091 itself.
Its too damned slow like this…about twice the xfer of a floppy, and my
tape restores are taking hours.