Re: [TUHS] core

[Johnny Billquist <bqt@update.uu.se>]

On 2018-06-20 18:55, Paul Winalski wrote:
> On 6/16/18, Johnny Billquist <bqt@update.uu.se> wrote:
>>
>> After Unibus (if we skip Q-bus) you had SBI, which was also used both
>> for controllers (well, mostly bus adaptors) and memory, for the
>> VAX-11/780. However, evaluation of where the bottleneck was on that
>> machine led to the memory being moved away from SBI for the VAX-86x0
>> machines. SBI never was used much for any direct controllers, but
>> instead you had Unibus adapters, so here the Unibus was used as a pure
>> I/O bus.
> 
> You forgot the Massbus--commonly used for disk I/O.

I didn't try for pure I/O buses. But yes, the Massbus certainly also 
existed.

> SBI on the 11/780 connected the CPU (CPUs, for the 11/782), memory
> controller, Unibus controllers, Massbus controllers, and CI
> controller.

Right.

> CI (computer interconnect) was the communications medium for
> VAXclusters (including the HSC50 intelligent disk controller).

But CI I wouldn't even call a bus.

> DEC later introduced another interconnect system called BI, intended
> to replace Unibus and Massbus.

I think that is where my comment started.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt@softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol