30 Jul
2014
30 Jul
'14
11:13 a.m.
I don't think these Read Direct and Write Direct were anything to do with
intersystem comms, as there were Channel to Channel adaptors which were I
think included with the original S/360 announcement...
.. but perhaps not. I am sure some one will say if its so...
Dave
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
On Behalf Of Chuck Guzis
Sent: 30 July 2014 18:53
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: microcode store (was Re: Looking to get into a MiniComputer...)
On 07/30/2014 10:20 AM, Dave G4UGM wrote:
Even though IBM tout compatibility even
System/360/370/XA/System/z has
"lost" instructions....
The original 360 had Read Direct and Write Direct which as fa as I can
tell accessed a socket somewhat akin to a bi-directional printer port..
.. but I have never seen any pictures....
I thought Read Direct and Write Direct were grandfathered into S/360 from
the 7040/7090 DCS setup, where it was essentially a channel-to-channel
interface. The idea being that you could have one system handle I/O for the
compute-intensive big machine.
Then the Vector Facility instructions have been
re-used. Of course
these needed a vector facility hardware thingy, which is no longer
made so I suppose that's fair enough....
Ah yes, IBM VECTRAN, the source of many ANSI X3 squabbles.
--Chuck