1 Apr
2008
1 Apr
'08
12:23 p.m.
I have used an RL11 in my 11/24 w/KT24 (to load real
2BSD from real magtape),
so I'm pretty sure it works fine in a 22-bit environment (but I can't say
if the KT24 just smooths over DMA buffer address issues or what). Dunno if
I believe that's exactly what the KT24 does. The F11 chipset (used on the
11/24 CPU board) has a full 22 bit MMU which addresses the 4Mbytes of
memory, but of course the Unibus only has 18 address lines, so DMA
addresses from peripherals (like the RL11) are only 18 bits wide. The
KT24 is the 'Unibus Map' -- a little MMU to extend those DMA addresses to
22 bits.
you can stuff an RL11 in an 11/70 or not, but I would
hope so (since there
really aren't any Unibus peripherals that "know" about 22 bits).
AFAIk the 11/70 has a Unibus Map as part of the CPU. The 11/44 certainly
does.
-tony