5 Jul
2006
5 Jul
'06
3:49 p.m.
On 7/5/2006 at 5:18 PM michael_short at comcast.net wrote:
The 1710 was an upgraded 1620. It had hardware to
handle interrupt
processing. There
were features on the 1710 that were ordereable on the
1620 such as A/D
conversion and
rudimentary bit manipulations. I think that the 1710
could also handle a
small number of
terminals.
It was pretty surprising what a 1710 could handle; The 1712 Mux could
handle about 300 signal sources/destinations. These could be analog,
digital (output) or make-break (input). And the 1710 had a real-time
clock, courtesy of the 1711 data converter. Interrupts were very
primitive.
"Terminal" usually meant a 1717 output printer with some sort of input
device (usually a few pushbuttons, but a keyboard was an option IIRC). You
could have up to 20 of those--and they had the bimodal alpha-or-numeric
personalities that the other 1620 I/O devices did. The 1717 was an
interesting bird in that you could write both numerical output and alpha
output in the same operation--there were embedded "mode change" escape
sequences.
One significant difference between the 1710 and 1620 was the 1710 had the
ability to test for its own hardware faults, instead of halting with a
CHECK STOP. Practically, I don't know how much good this was, but one
could test for parity errors and other faults.
It's pretty amazing what what amounts to a 5-bit computer (I don't count
the parity bit) running with a 100 KHz clock rate and doing its math by
memory table lookup (well, the Cadet did, anyway) could do.
Cheers,
Chuck
http://www.99-bottles-of-beer.net/language-ibm-1620-sps-916.html