18 Feb
2022
18 Feb
'22
12:35 p.m.
On Feb 18, 2022, at 3:18 PM, Gary Grebus <glg at
grebus.com> wrote:
On 2/18/22 09:46, Paul Koning wrote:
I didn't remember all those details, thanks.
There also was an effort at one point to adopt FutureBus in DEC systems. We did a pile of
design in the network architecture group to figure out how to handle interrupts and bus
cycles efficiently; I don't remember if anything actually shipped with that stuff.
paul
...The 9000 also had its own I/O bus, XMI,
different from BI. I don't know how its performance compares, whether it was worth
the effort.
XMI already existed as the system bus for the VAX 6000 series machines. I/O on the VAX
6000's was via an XMI-to-BI bridge. I don't remember the exact performance specs
on XMI, but it was wider and faster than BI.
XMI was then also used as one of the possible I/O buses on the VAX 10000 and AlphaServer
7000 and 8000 series machines, via a system bus to XMI bridge. So the XMI I/O adapters
were common across all these series of machines.