27 Nov
2014
27 Nov
'14
8:55 p.m.
From: Clem Cole <clemc(a)ccc.com>
two issues. first DEC subsetted the modem control
lines so running
modems - particularly when you wanted hardware flow control like the
trailblazers - did not work.
?? We ran dialup modems on our DZ11s (1200 bps Vadics, IIRC) with no problems,
so you must be speaking only some sort of high-speed application where you
needed the hardware flow control, or something, when you say "running modems
... did not work".
Although, well, since the board didn't produce an interrupt when a modem
status line (e.g. 'carrier detect') changed state, we did have to do a kludge
where we polled the device to catch such modem control line changes. Maybe
that's what you were thinking of?
To Dave the DZ was great because it was two boards to
do what he
thought was the same thing as a DH
To prevent giving an incorrect impression to those who 'were not there', each
single DZ hex board supported 8 lines (fully independent of any other cards);
the full DH replacement did need two boards, though.
Noel
27 Nov
27 Nov
9:47 p.m.
New subject: What's with the DZ-11?
The original Trailblazers were special modems that on a good like could approach 19.2KB.
T They also had special software that recognized when UUCP protocol stuff was being
transfer and apportion the bandwidth and spoof the ACKS on the protocol to increase the
UUCP throughput.
Believe me, running a bunch of 9600 data transfers on a DZ will pretty much saturate the
unibus in a hurry. The thing didn’t even have the ability to operate at 19.2.
The statement is correct. The DZ doesn’t support or even make programatically the
CTS/RTS lines and as you did indicate, the RI/CD didn’t generate interrupts and had to be
polled.
9:50 p.m.
New subject: What's with the DZ-11?
To prevent giving an incorrect impression to those who 'were not there', each
single DZ hex board supported 8 lines (fully independent of any other cards);
the full DH replacement did need two boards, though.
Eh? The DH/DM from Able was a single hex board and it supported 16 lines.
28 Nov
28 Nov
1:57 a.m.
New subject: What's with the DZ-11?
On Thu, 27 Nov 2014, Noel Chiappa wrote:
To prevent giving an incorrect impression to those who
'were not there',
each single DZ hex board supported 8 lines (fully independent of any
other cards); the full DH replacement did need two boards, though.
And was really really expensive, which is why we had DJ-11s instead, hence
our rapture on the coming of the DZ-11.
Oh, and I'm a software person, with a good knowledge of hardware (I was
forever trying to tell the hardware bods that it was their problem and not
mine, and I practically had to rub their noses in it).
DEC used to fob us off because we ran Unix; it was only when DECEX became
available that the overlapped-seeks issue on the RK-11 was finally
acknowledged, as RSX/RSTS didn't use that feature, and MAINDEC didn't prod
it.
--
Dave Horsfall DTM (VK2KFU) "Bliss is a MacBook with a FreeBSD server."
http://www.horsfall.org/spam.html (and check the home page whilst you're there)
7:04 p.m.
New subject: What's with the DZ-11?
DEC used to fob us off because we ran Unix; it was only when DECEX became
available that the overlapped-seeks issue on the RK-11 was finally
acknowledged, as RSX/RSTS didn't use that feature, and MAINDEC didn't prod
it.
That was the story of my life running the UNIX machines, not only from DEC and
other
service guys but also the manufacturers themselves. Sometimes I had to bluff and
say i was experiencing the problem with the proprietary OS. I had to remember not
to use our slang for the other OS’s (both HP’s MPX and Gould’s MPE we referred to
as Might Pour Excuse).
3676
days inactive
3677
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4 comments
3 participants
participants (3)
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Dave Horsfall -
jnc＠mercury.lcs.mit.edu -
Ronald Natalie