43 years ago around this time the Internet we use to communicate with
was probably made possible because of TCP/IP, or Transmission Control
Protocol/Internet Protocol created at Stanford University. Today 3
billion people are on the net but really made it possible for this
extravagant number was the microcomputer created at around the same
time ? the Micral in France and 4004 processor machines in the U.S.
Our hobby supported through this web site keeps this history alive.
Hurrah!
Happy computing.
Murray :)
PS This week marks the 100th anniversary of Einstein?s Theory of
General Relativity though published in 1916 according to Wikipedia.
> From: Fred Cisin
> It was inevitable that eventually there would be movementS towards
> standardization of protocols on the arpanet.
Actually, TCP/IP grew out of the desire to interconnect two very different
kinds of network - the ARPANET, and something called the Packet Radio Network
(and also a thing called SatNet). The technical details of each were such
that it just wouldn't be feasible to extend the ARPANET protocols to work on
them too, they were fundamentally different (I'm not talking about low level
things like packet size, but higher-level concepts, like reliability, etc);
something new was required - and TCP/IP looks _very_ little like the
ARPANET's NCP.
> From: Chuck Guzis
> I do miss the web-less Internet in some respects. People were more
> polite back then--at least in their written communication.
I snorted and started coughing when I read that! :-) Usenet had massive flame
wars long before the Web existed!
Noel
never heard of it - Ed#
In a message dated 10/23/2015 10:08:44 A.M. US Mountain Standard Tim,
paulkoning at comcast.net writes:
How many people consider the Micral to be of that level of significance?
but! now that we have heard of it
SMECC museum wants one!
Ed#
In a message dated 10/23/2015 10:43:50 A.M. US Mountain Standard Tim,
rodsmallwood52 at btinternet.com writes:
Nope never heard of it either
Rod
On 23/10/15 18:29, COURYHOUSE at aol.com wrote:
> never heard of it - Ed#
>
>
> In a message dated 10/23/2015 10:08:44 A.M. US Mountain Standard Tim,
> paulkoning at comcast.net writes:
>
> How many people consider the Micral to be of that level of
significance?
> OK, I've cracked the part number code. The things we are looking for are:
> 7101J50 CxE
> 7108J50 CxE
> ...
> the C+K Web site showed two places (Electro-Sonic and
> Online-Components) stocking 7101J50 CQE2's .. investigating further now.
OK, so I've ordered 10 7101J50-CQE2's from Online (that was their minium
order, sigh). _Iff_ they fit into the old front panels, I'll let the list
know.
Nobody had the 7108J50C's (the momentary contact ones), but if the 7101J50C's
are the Right Thing, I'm prepared to order a batch of the 7108's from C+K;
the minium order looks like 40 or so (that's how many the distributors who
had the 7101J50-CQE2's had ordered), which I can do off the cuff (and resell
at cost to anyone who needs one); if the minimum is larger, we'll have to
reconsider how to proceed.
The ones from Online are like $5 each, which sounds a lot for a switch, but
if you're got a PDP-11 with a non-operable front pable because a switch is
busted, it's downright cheap! Also, that will of course include the
distributor's markup - if we bought a batch directly from C+K, we might be
able to get that down quite a bit.
Anyway, let's see if the 7101J50-C's fit, then we can discuss how to proceed.
Noel
Hey guys,
Further to our conversation - I was looking at this beast:
http://www.ebay.com/itm/Teletype-equipment-1-model-28-writer-1-reperforater-
1-50vdc-supply-etc-/121791042544?hash=item1c5b4fd3f0:g:UR8AAOSwnDZUJHWs
Wasn't sure if it was two units? The first couple of pics look different.
Anyway, if I understood correctly, it was possible (and possibly done in the
1970s by hobbyists) to convert one of these baudot teletypes to ASCII and
use with a computer? This one is out of my reach since the auction is pick
up only. But I kind of like the look of the Model 28 and I understand
they're pretty bulletproof once you have them working. I'm just not sure if
this would work, and if this particular one is ASR or what, because it
mentions a reperforator and from what I read 28s that came with that had a
tape reader also?
Brad
> From: Dave Wade
> What I found hard was obtaining centre off switches as it appear from
> this picture ... that PDP-11 Switches may be flipped up or down, or is
> that not true?
No, they are all 'standard' (except for the mounting) SPST switches; most
(e.g. the address/data bits) are normal two-position, although some (LOAD
ADDR, DEPOSIT, EXAM, START and CONTINUE, IIRC) are momentary-contact. The
'toggle' (the plastic part that fits over the switch) has an off-center shaft
that goes around the switch's metal actuating shaft, so that the toggle can be
level when the switch is in the 'un-set' position.
Some of the switches are installed 'the other way around', and they depress
instead of lift (typically the address-data switches lift, and the function
ones depress, although there are exceptions - e.g. DEPOSIT is a lift).
> I believe they were made by C&K who are still in business. I wonder if
> it is worth approaching them.
If they're not actually still availble - see below.
> The double pole version appears to be still "stocked", I see Farnell
> has some in the UK
That is _almost_ the exact switch (I just about had a heart attack when I saw
them, and started to order some until I realized they weren't quite it); it
has the right mounting mechanicals (note the two triangular side plates with
the holes through the tips - the toggle have pins which go into the holes,
and the toggle pivots on them).
Alas, it's DPDT, not SPST. And it's momentary contact (although each PDP-11
panel does contain some momentary-contact switches).
But if C+K is still making _these_, they should have no problems making the
SPST version - if, in fact, they are not still in production.
I tried looking through the catalog at that site, to see if I could find the
SPST version, but no luck. (Although maybe I'm just a klutz about that site -
it wasn't easy for me to use.) Maybe your parts-search-fu is better than mine?
Noel
> It's just a matter of working out what the part number would be!
OK, I've cracked the part number code. The things we are looking for are:
7101J50 CxE
7108J50 CxE
where x is a letter selecting the contact material (about 10 options,
including gold, silver, gold-over-silver, etc). The 7101's are the normal
permanent contact, the 7108's are the momentary contact used in a few
positions.
The ones Dave found are ZQE's, the 'Z' meaning they are solder lugs, not PCB
through-hole lugs, and the 'Q' meaning silver contacts.
A Google search didn't find any 7101J50 C's, only Z's. But the C+K Web site
showed two places (Electro-Sonic and Online-Components) stocking 7101J50
CQE2's (the trailing '2' means 'black actuator' - their name for what I've
been calling the toggle, the plastic part the finger touches); investigating
further now.
Noel
Hi Guys
We seem to have a bit of a rush on to do reproductions of
mainly digital front panels, bezels and switches.
Before we all run round and go through the same learning curve perhaps
we can pool our knowledge and
and allocate getting different parts sourced/made to different people.
I am now up to speed on the perspex panels for all models they were
actually used on, from pdp8 up to 11/70.
I also have a proven production system. No fancy machines just perspex
(plexiglas) blanks and silk screen process
as per the the originals.
So who wants to do
1. Bezels
2. Lever keys (pdp8 type and PDP11 type )
3. Key/lamp pcbs (connect as replacements to original systems
or to microprocessors)
4. Micro processor and custom software to drive the above.
( Suggest Rainbow Pi as Its low cost and is known to run
the right simulations)
I can quite understand somebody wanting to do the whole process themselves.
However not everybody who would like a nice full size 8 or 11
functional front panel has the time, knowledge
or access to the right resources to do it.
I shall now go and hide behind my six foot / nineteen inch main rack in
case of heavy flack
Rod Smallwood
> From: Alexandre Souza
> Easily done if I had the original part on hand
We have plenty of the original bezels, from which it would be easy to cast molds
(the same part is used on the 11/45 and 11/70, unlike the rest of the front
console).
The real issue in any front panel recreation is going to be the switches (not
the plastic toggles, the actual electrical device). Both the /45 and /70 used
the now-apparently-unobtainium version with the intergral metal plate to hold
the switch in place in a metal holder plate. So a recreation front panel is
going to have to have some new mechanical design, to allow use of standard
micro-switches - and that's probably going to mean a re-design of the plastic
toggles, as those attached to side-plates on the original toggle switches.
(That's all a bit difficult to describe in words; a picture will make it
obvious, if anyone wants to know more.)
I wonder how big an order of switches would be required before some
switch-making firm could be convinced to do a run? Maybe whoever made the
'back in the day' still has the tooling to do so gathering dust in an old
room....
> From: David C. Jenner
> How about making a version for a REAL PDP-11/70 front panel, and one
> for a REAL PDP-11/45 front panel, for those of us who have such stashed
> away waiting for the right simulator to come along...
To do that is going to require exactly emulating the interface to the CPU,
which is not going to be entirely trivial. Physically, the signals all come
over flat ribbon cables to standard Berg connectors, so that won't be hard,
but I doubt the interface is documented, someone will have to puzzle it out
by reading prints - and probably looking at a working one with a logic
analyzer.
Also, powering the front console requires an unusual AMP connector shell,
although that may still be available? And of course one could always bodge
the power connection...
Noel
