24 Feb
2021
24 Feb
'21
5:16 p.m.
On Feb 24, 2021, at 7:06 PM, Noel Chiappa via cctalk
<cctalk at classiccmp.org> wrote:
It's faintly true if you look at the Massbus adapter, rather than the cable. But only
faintly. There's a good reason why the big disks on many DEC machines were Massbus
devices until MSCP arrived. It's quite clear on Unibus PDP-11s, which needed Massbus
both for speed and for a cleaner answer to more-than-18 bit addressing.
paul
From: Chris Zach
technically the MASSBUS cable is just an
extension of the Unibus
No.
For one thing, the MASSBUS has no lines for carrying memory addresses. So
there is no way to even build a box that 'translates' MASSBUS to UNIBUS; the
semantics ('the things you can say', basically) of the two busses are so very
different.