29 Feb
2020
29 Feb
'20
3:58 a.m.
On Fri, 28 Feb 2020, Clem Cole wrote:
DZ-11 sucked... for a number of reasons, the SW issue
being just part of
them, but they were short pinned and really did not do modems well,
particularly high-speed ones like the Trailblazer. As you said, you
could make them work, but why bother?
We used ours for local terminals only; 8 DZ-11s on the 11/70 worked fine
(I don't recall how fast, but probably around 2400/4800). As I said, it
came down to the driver.
Unix folks figure out the best idea was to use the
Able DH/DM -
cheaper, only one unibus slot for 16 ports (as opposed to 2 for the DZ),
fully wired on the DB25 end, hardware flow control and just worked
better in that is will DMA. What was not to love...
Sure, but then DEC Field Circus won't touch the box.
FWIW: One of the guys behind DZ (who I will leave
nameless) also
screwed up the first serial port on the Masscomp MC/500 after he left
DEC. I got there too late to fix it in the first version of the CPU
board. So it was not fixed until I tore him a new one and educated him
on how RS-232 actually worked (I was the first lead for the data com
group as well as 1/2 the OS team). I never quite understood why HW
folks often though of the serial port as '3-wires' -- sigh.
Heh heh :-) I don't think I've ever seen RS-232 used "properly" i.e.
implementing DSR/DTR or RTS/CTS for other than flow control etc, and using
the secondary pins as well.
-- Dave