> Here's a Gootoob video (11m): it's a mechanical marvel!
A wonderful model, but quite unlike a TTY 37, where sender
and receiver are the same machine.
Doug
> I think RS took it and left it behind someone's car at one as a practical joke.
That behemoth was built to last. It would surely stop a car.
Moving it single-handed would be quite a feat. When Andy Hall
retired his, he was able to push it as far as his back porch,
where it remained for more than a year.
Under the keyboard was remarkable mechanical crossbar
encoder that dripped machine oil. Fortunately the operator's
knees were protected by a drip pan. The oil smell led me
to keep mine in my workshop; its fragrance reminded
me of the first major piece of computing equipment I saw
as a child: Vennevar Bush's mechanical differential
analyzer, a room-size table of shafts, gears and integrators
that was redolent of machine shop.
Doug
Hopkins had a KSR37 that was our standard word processing output for a long time before the daisy wheel printers started showing up.
It even had the "greek box" so when eqn or whatever wanted that, it just sent shift-in/shift-out (control-n, -o). Years later I managed to pick up a surplus ASR37 from Rocky Flats. I had it in my kitchen for years on a modem. It was great fun to have one of the few terminals that nroff would send all those ESC-8/9 things for the vertical positioning without needing an output filter. No greek box, though. It also had a giant NEWLINE key and didn't need to have the nl mode turned on. Amusingly the thing would sit there quiet until the modem was powered up and then DSR ready would bring it to life. When CD came up an giant green PROCEED light illuminated above the keyboard. The paper tape unit was a monster side car. I never got around to programming the "here-is" drum.
I think RS took it and left it behind someone's car at one as a practical joke.
ANTS was written by Gary Grossman and the experience with ANTS and ANTS 2 was the direct inspiration for NCP Unix (which was probably what Mike installed):
http://chiselapp.com/user/pnr/repository/TUHS_wiki/wiki?name=ncpunix
The source for NCP Unix is available on the Unix Tree webpage:
https://minnie.tuhs.org//cgi-bin/utree.pl?file=SRI-NOSC
> Date: Sun, 3 Jun 2018 13:42:00 -0400
> From: "Ron Natalie" <ron(a)ronnatalie.com>
>
> While Mike and I still shared an office in 394, the ENIAC room was where the IMP 29 on the ARPANET was and a PDP-11/40 system that ran a terminal server called ANTS (ArpaNet Terminal Server) complete with little ants silkscreened on the rack tops. When the ARPANET went to long leaders, Mike replaced that software with a UNIX host giving the BRL their real first HOST on the Arpanet. Years later I recycled those racks (discarding the 11/40) to hold BRL Gateways (retaining the ants).
(Yeah, I was asked to not use "RIP", so...)
We lost J. Presper Eckert back in 1995; he was a co-inventor of ENIAC (one
of the world's first "electronic brains").
--
Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."
Clem Cole:
WE212 modems worked on dz11 for input but just barely and could not use
a WE dialer for output (who's number I now forget). Remember the AT
command dialer stuff was not originally a standard from the telcos.
The modems were independent of the dialer (which used the RS-4xx
standard and I also have some where and I forget the number).
=====
There was certainly some WECo modems-in-a-rack-with-one-dialer setup
that could be driven by DZ11s. I know that because that is what the
UUCP node `research' used in the 1980s, when I was at Bell Labs.
I don't know what the modem hardware was; maybe it was newer than
what Clem describes, or maybe someone (likely Bill Marshall or Joe
Condon) made some special hardware to make it work. But the UNIX
side of things was a VAX-11/750 running Research UNIX with a DZ11;
I'm quite sure of that.
I'm also sure that the modems were genuine WECo and spoke the 212
protocol, max speed 1200bps.
Aside: when I arrived at the Labs, the standard in the Computing
Science Center was that everyone got a Jerq terminal (AT&T 5620,
commercial descendant of the Blit) at work and at home. For the
home end everyone got a modem with attached telephone (that's the
way the official Bell stuff came back then) and a second phone
line paid for by the Labs. There was a pool of modems dedicated
to dialin for people working from home.
A few months later, it was discovered that a Japanese modem
manufacturer (Fujitsu? I forget) had a 9600bps modem that required
a four-wire leased line but had a reasonable cost, and that New
Jersey Bell had a new offering for leased lines at a reasonable
cost too. So the Labs paid for a pair of the modems and a leased
line for each of us, and we all brought the old 212 modems back
in when convenient, and most of the second phone lines were
cancelled. (A few people wanted to keep them, because they were
business lines from which one could make calls to BTL offices etc
without having to submit your home phone bills for reimbursement.)
The modems had LCD status displays. In the early samples we had
for initial testing, I vaguely remember a few spelling errors in
the status messages; in particular SIGNAL QUARITY IS POOR. The
error had been fixed in the big bulk order.
There was one more step in the evolution of RS-232-to-home: several
years later New Jersey Bell began offering a new service called
Co-LAN to those served by certain central offices (including me).
The customer was given a box with input phone jack, output phone
jack, and a DB25 connector. The latter afforded a serial connection
to the CO, multiplexed with the POTS signal (presumably a forerunner
of what is now called DSL). At the CO, the serial line was plugged
into a Datakit switch. So I would turn on my terminal and get a
Datakit prompt, type a network address referring to a system on
our Datakit network at MH, type a network-access password, and
I was connected the same as if I were at work, at 9600 bps.
New Jersey Bell hoped to sell both the service and Datakit to
other corporations; hence the password, so customers could get
only to the networks for which they were authorized. I don't
know whether that happened much. It was sure convenient for
Bell Labs, though.
Norman Wilson
Toronto ON
On 31.05.18 04:00, Pete Turnbull<pete(a)dunnington.plus.com> wrote:
> On 30/05/2018 23:10, Johnny Billquist wrote:
>> On 30.05.18 02:19, Clem cole wrote:
>>> 1). If you grab ^s/^q from the alphabet it means you can send raw 8
>>> bit data because they are valid characters (yes you can use escape
>>> chars but it gets very bad)
>> But this has nothing to do with 8 bit data.
> [...]
>> What you are talking about is simply the problem when you have inband
>> signalling, and is a totally different problem than 8bit data.
> True, but what I believe Clem meant was "binary data". He did write
> "raw data".
Clem originally said:
"And the other issue was besides not enough buffering DZ11s and the TU58
assumes software (^S/^Q) for the flow control (DH11s with the DM11
option has hardware (RTS/CTS) to control the I/O rate. So this of
course made 8bit data diificult too."
And that is what I objected to. If we're talking about just getting data
through a communications channel cleanly, then obviously inband
signalling like XON/XOFF is a problem, but that was not what Clem claimed.
By the way, while I'm on this topic. The TU58 (aka DECtape II - curse
that name) initially did have overrun problems, and that was because the
protocol did not have proper handshaking. There is flow control when the
TU58 sends data to the host, but there is no handshaking, which
amplifies the problem with flow control on that device. The protocol the
TU58 uses is called RSP, for Radial Serial Protocol. DEC realized the
problem, and modified the protocol, which were then called MRSP, or
Modified Radial Serial Protocol, which addressed the specific problem of
handshaking when sending data to the host.
But in addition to the lack of handshaking, the TU58 is normally always
expected to be connected to a DL11, and the DL11 is the truly stupid,
simple device that only have a 1 character buffer. So that interface can
easily drop characters on reception. Flow control or not. And the TU58
is not really to blame. And if you have an updated TU58 which uses MRSP,
you are better off.
>> RTS/CTS signalling is certainly a part of the standard, but it is not
>> meant for flow control. It is for half duplex and the way to signal when
>> you want to change the direction of communication.
>>
>> It is meant for*half duplex* communication. Not flow control.
> Actually, for both, explicitly in the standard. The standard (which I
> have in front of me, RS232C August 1969 reaffirmed June 1981) does
> indeed explain at length how to use it for half duplex turnaround but
> also indicates how to use it for flow control. It states the use on
> one-way channels and full-duplex channels to stop transmission in a
> paragraph before the paragraph discussing half duplex.
Using RTS/CTS for flow control have eventually made it into the
standard, but this only happened around 1990 with RS-232E-E. See
https://groups.google.com/forum/#!original/comp.dcom.modems/iOZRZkTKc-o/Zcd…
for some background story on that.
And that obviously is way after DEC was making any of these serial
interfaces.
Wikipedia have a pretty decent explanation of how these signals were
defined back in the day:
"The RTS and CTS signals were originally defined for use with
half-duplex (one direction at a time) modems such as the Bell 202. These
modems disable their transmitters when not required and must transmit a
synchronization preamble to the receiver when they are re-enabled. The
DTE asserts RTS to indicate a desire to transmit to the DCE, and in
response the DCE asserts CTS to grant permission, once synchronization
with the DCE at the far end is achieved. Such modems are no longer in
common use. There is no corresponding signal that the DTE could use to
temporarily halt incoming data from the DCE. Thus RS-232's use of the
RTS and CTS signals, per the older versions of the standard, is asymmetric."
See Wikipedia itself if you want to get even more signals explained.
If you have a copy of the 1969 standards document, could you share it? I
was trying to locate a copy now, but failed. I know I've read it in the
past, but have no recollection on where I had it then, or where I got it
from.
>> The AT "standard" was never actually a standard. It's only a defacto
>> standard, but is just something Hayes did, as I'm sure you know.
> Except for ITU-T V.250, which admittedly is a Recommendation not a Standard.
This also becomes a question of who you accept as an authority to
establish standards. One could certainly in one sense say that the Hayes
AT commands were a standard. But all of that also happened long after
DEC made these interfaces, and as such are also pretty irrelevant. The
link to the post in news back in 1990 is from the standards
representative from Hayes, by the way. So they were certainly working
with the standards bodies to establish how to do things.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
On 2018-05-29 04:00, Clem cole<clemc(a)ccc.com> wrote:
>
> And the other issue was besides not enough buffering DZ11s and the TU58 assumes software (^S/^Q) for the flow control (DH11s with the DM11 option has hardware (RTS/CTS) to control the I/O rate. So this of course made 8bit data diificult too. And as Paul points out, with HW flow the priority could have been lower. But the HW folks assumed a so called 3 wire interface because they thought they were saving money.
Uh? Say what? What does XON/XOFF flow control have to do with 8bit data?
And no, DEC was not trying to save money. They were actually sticking to
the standard. Something very few companies managed to do, especially
when it came to the RS-232 standard.
The "hardware flow control" is actually an abuse of the half duplex
signalling.
And it does not necessarily work as you might expect if modems are in
the middle.
You could get by with just three wires on serial ports, but DEC usually
did want people to have more wires connected, in order to detect when a
device was connected or not. But no, they did not abuse the half duplex
control to do hardware flow control. The DZ11 also have partial modem
control. You cannot run them in half-duplex mode, and they do not
support the secondary channel stuff, but they do support more than just
the 3 wires.
> A few years later when people tried to put high speed modems like the Trailblazers on them, let’s say the Unix folks quickly abandoned any hope. Ken O’Humundro at Able Computer has quite a business in his ‘DHDM’ board that was cheaper than the DZ, more ports, full DMA and of course full hardware flow control.
Yes. It's essentially a DH11 with a partial DM11 on just one board,
while the original DH11/DM11 was a fully 9-slot backplane. So it was a
really good alternative. The DH11 is much better than the DZ11, but did
in fact cost more. The Able board gave the DH11 capabilities at a much
lower cost, and taking much less space in the box. And it actually
performed better than the DH11. But it did not support the full
functionality of the DM11. But what was lacking was the half duplex
stuff, which noone really cared about anymore anyway.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
On Tue, May 29, 2018 at 9:10 PM, Dave Horsfall <dave(a)horsfall.org> wrote:
> On Wed, 30 May 2018, Johnny Billquist wrote:
>
> Uh? Say what? What does XON/XOFF flow control have to do with 8bit data?
>>
>
> Err, how do you send data that happen to be XON/OFF? By futzing around
> with DLE (which I've never seen used)?
Right - you have to escape things and it is a real mess. I have seen some
of the SI/SO/DLE stuff in mechanical systems like ticker tape. I never saw
a real 8-bit interface try to do it and succeed -- its messy and suspect
when data overruns occurs all hell break loose. By the time of 8 bits and
speed of 9.6K protocol's like UUCP, or IP over serial did not even bother.
I suspect in the old 5-bit baudot code times, it was more popular to get a
larger character set, but the speeds were much slower (and the UART not yet
invented by Gordon Bell).
By the time of the PDP-11, hardware flow was the norm in many (most)
interfaces. I never understood why DEC got ^S/^Q happy. You can really
see the issues with it on my PiDP-8, running DOS/8 because the flow is done
by the OS and its much to late to be able to react. So you get screens
full of data before the ^S is proceeded.
Once Gordon creates the UART, Western Digital licensed it and made it into
a chip which most folks used. DEC started to use the WD chipset in PDP-8
serial interfaces - it always struck me as strange that HW flow was not
used more. The KL11/DL11 supported the wires, although the SW had to do
the work. As I said, MacNamara supported it in the DH11, if I recall (I
don't have the prints in any more), he put an AND gate in the interrupt
bit, so the OS does not get an transfer complete interrupt unless the "I'm
ready" signal is available from the other side.
When I lectured data com to folks years ago, I liked to express the ECMA
serial interface in this manner:
There are 6 signal wires and one reference (signal) ground:
1. Data XMT (output)
2. Data RCV (input)
3. I'm Alive (output)
4. He's Alive (input)
5. I'm Ready (output)
6. He's Ready (input)
Everything else is either extra protocol to solve some other problem, or is
for signal quality (*i.e. *shielding, line balancing etc.). The names of
which signals match to which actual pins on the ECMA interface can be a
little different depending on the manufacturer of the 'Data Communicating
Equipment (DCE - *a.k.a.* the modem) and the Data Terminating Equipment
(DTE - *a.k.a.* the host).
BTW: ECMA and the WE did specify both signal names and the connectors to
use and I think the European Telco's did also (but I only ever saw a German
spec and it was in German which I do not read). DCE's are supposed to be
sockets (female and originally DB25)s and DTE's were suppose to plugs
(male). If you actually follow the spec properly, you never have issues.
The problem was the a number terminal manufactures used the wrong sex
connector, as a lot of them never read the specs [the most famous being the
Lear Siegler ADM3 which was socketed like a DCE but pinned as a DTE -
probably was it was cheap and thus became very popular).
Also to confuse things where it got all weird was how the DCE's handled
answering the phone. And it was because of the answering that we got all
the messy stuff like Ring, Data Set/Terminal Ready/Carrier and the like.
The different DCE manufacturers in different countries had different answer
protocols, than the original Bell system. IIRC the original WE103 needed
help from host. Support for Auto-answer was a later feature of the WE212.
The different protocols are all laid in well in another late 60s/early 70s
data com book from an UMass Prof, who's name I now forget (his book is
white with black letters called 'Data Communications' , as opposed to
MacNamaras dark blue DEC Press book 'Principles of Data Communications').
So ... coming back to Unix for this list... AT&T owned Western Electric
(WE) who was the largest US manufacturer of DCE's [see 1949 law suit/the
consent decree et al]. In fact at Bell Labs, a lot people using UNIX did
not have 'hardwired terminals' - they had a modem connection. So, Unix
as a system and tends to have support for DTE/DCE in the manner WE intended
it to be as a result. It's not surprising that see it in the solutions
that are there.
ᐧ
