30 Jul
2014
30 Jul
'14
10:52 a.m.
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