25 May
2016
25 May
'16
8:48 a.m.
On 05/24/2016 11:47 PM, Chuck Guzis wrote:
On 05/24/2016 08:48 PM, Jon Elson wrote:
No, the 360/20 was a 16-bit ISA, somewhat
compatible with
the 360 layout, but not really a 360. All registers were
16-bit, only 8 registers, lots of differences. But, EVEN
the 360/20 had a 16-bit memory and data paths.
The /20 had no channels, there were only 4 device types that
could be directly attached to the built-in controllers.
The 360/30 was a full 360 implementation (16, 32-bit
registers, floating point was available as an option), but
the underlying hardware was 8-bit wide.
The 1130 was for a totally different market, the /20 was
intended for very specific uses in 360 shops, and maybe as
an entry-level "foot in the door" to move totally tab card
shops into the 360 family. The only /20s I ever saw were
used as offline spool printers and card readers in large 360
shops.
Jon
For sure! The 360/30 was an 8 BIT machine, 8-bit
memory, 8-bit data
paths, etc. Really hobbled the performance, and restricted the
peripherals that could be attached. The models /22 and /25 had 16-bit
memory and data paths.
Do you mean the 360/20? On the topic, were the 20 and 40
the only
members of System 360 to use TROS?