better Kodak reorganization

Discussion in 'Darkroom Developing and Printing' started by Dale, May 6, 2013.

  1. Dale

    Eric Stevens Guest

    What you describe as "your imagination" is in fact Wikipedia. You
    should write to them and connect their errors.

    There is very little information on the Internet about the No4
    Crossbar but
    tells us something:

    "1940s & 1950s: Automated switching

    Automation came to long distance switching when AT&T installed the
    first No. 4 crossbar switch in Philadelphia in 1943. Now a single
    operator built up the needed circuit by dialing a series of routing
    codes to instruct this automatic electromechanical switch. Dialed
    routing codes soon gave way to the familiar area codes, which the
    switch itself could translate into the needed routing information.
    AT&T soon modified the switch to handle customer-dialed long
    distance calls; the modified design became the No. 4A crossbar
    switch. No. 4A crossbar switches and direct-distance dialing spread
    to subscribers across the country during through the 1950s.
    Call-completion time dropped to 10-20 seconds."

    The No 4 Crossbar switch appears to be nothing more than a manually
    set crossbar, with the setting controlled by the operator via a dial
    on their desk. It was no more programmable than an ordinary telephone
    of the period.

    There is nothing in the above to say when the No 4 Crossbar was
    supplanted by the No 4A but says:

    "Direct distance dialing ("DDD") started in the United States in

    That's a fairly specific statement which sounds like it refers to the
    introduction of the No4a Crossbar.
    Eric Stevens, May 12, 2013
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  2. I have read what Wikipedia says on the topic, and they
    didn't connect the dots for you the same as for everyone
    else Eric.

    Keep in mind that I didn't learn about crossbar
    switching systems either yesterday or from reading
    Wikipedia. I worked for years in a Class 4 office...
    and for decades at non-switching sites with trunking
    to Class 4 offices.

    It happens that the Autovohn system in Alaska used 4A
    Crossbar switches located at Neklasson Lake, Pedro Dome,
    Kalekaket Creek, and Big Mountain. They were later
    replaced with DMS-200 switching systems at Pedro Dome
    and Neklasson Lake. At about that same time the
    commercial PSTN in Alaska installed 3 DMS-200 systems,
    one at Anchorage, one near Juneau at Lena Point, and one
    in Fairbanks. In 1996 a 4ESS was added in Anchorage and
    the DMS-200 switches at Lena Point and Fairbanks were
    decommissioned. The Autovohn DMS-200's were
    decommissioned at about the same time.
    Now you can see the significance of what I previously
    wrote. "Automation" is the term used because the
    "switch" is now in fact a computer. And the point was
    that AT&T's Bell Labs had been working on them prior to
    WWII, which is clearly true if production models were
    first installed in 1943. In fact Bell Labs was testing
    operational prototypes at least as far back as 1937.
    It has a stored program common control system that
    allows a Network Administrator to change the exact
    routing that results from whatever the operator actually
    dials. Hence on Monday when an Operator dialed 123 as
    an access code it might result in calls going to area
    code 312 to be routed via Trunk Group A, but if a new
    Trunk Group that has been installed six months
    previously and is then enabled by reprogramming
    overnight, on Tuesday when the same Operator wants to
    route a call to area code 312 and dials a 123 access
    code... nothing that happens Tuesday morning will
    physically be the same as what happened on Monday
    evening. And the Operator of course does not even know
    there was a change.

    Prior to that either the Operator would be instructed to
    use a different jack field to place calls that new set
    of jacks would need to be wired to the appropriate
    trunks, or the original jack field would have to be
    entirely rewired overnight.

    The 4A Crossbar accepted routing calls dialed by
    customers as well as by Operators. It had a "Card
    Translator" using metal punched cards to program
    routing. The A4A Crossbar was not actually equipped
    with a Card Translator, and when it because available
    the designation was changed to 4A Crossbar.
    That is correct. Or almost correct.

    The A4A Crossbar was installed starting in early 1950.
    The first 4A Crossbar was installed in May 1953 in
    Scranton PA.

    Electronic Translators began use in 1969, mostly replacing
    the Card Translators.

    Starting in 1976 most Crossbar switches were equipped with
    CCIS6 (Common Channel Interoffice Signaling) to replace
    Multi-Freq signaling and Single Frequency trunk supervision.

    The first 4ESS was installed in early 1976 and the last 4A
    was installed in late 1976.

    There were over 200 4A switches installed in the US. That
    compares to the current count of 135 4ESS switches.

    Try reading and understanding the two quoted paragraphs
    above. Your digression into minute trivia from
    Wikipedia that you don't understand is of no value at
    all. If you were asking if that were what it means
    you'd have a good question; instead you stand up and
    proclaim you know what the significance of something is,
    and preach to someone that saw and worked with these
    Floyd L. Davidson, May 12, 2013
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  3. Be careful with semantics. There is a reason everyone
    calls those devices computers, even though they were not

    They weren't "programmable" in the sense we use today,
    mostly because Bell Labs did not invent that concept
    until later! But they did have a hard wired program,
    they were computers, and the program could be changed.
    It just happens that the uses those computers were being
    put to did not require changing the program as such. A
    fixed result was all that they needed at that time.
    Floyd L. Davidson, May 12, 2013
  4. Dale

    Eric Stevens Guest

    They were computers in the same sense that a Marchant
    electro-mechanical desk calculator was a computer. But they are not
    computers in the modern sense of the word or as it is applied to
    They didn't invent it all! Maybe it originated with Charles Babbage
    but certainly the concept was incorporated in the computer of Konrad
    Zuse (1936) and Atanasof-Berry (1937).
    So does the lighting in my house.
    So they didn't have a stored program.
    Eric Stevens, May 12, 2013
  5. You don't read well, do you.
    Floyd L. Davidson, May 12, 2013
  6. Dale

    Eric Stevens Guest

    Bullshit to it being a computer. It responded to the operator's dialer
    in the same way the No5 crossbar devices responded to the callers
    In exactly the same way the lighting in my house operates via a stored
    program if switches are operated and wires are rerouted.
    Eric Stevens, May 12, 2013
  7. On 05/12/2013 02:45 AM, Floyd L. Davidson wrote: That site specifically
    states "The Complex Number Computer was not programmable". (The Complex
    Number Computer was not called the Mk 1 until later). It goes on to say
    "the Models III and N were the first of the Bell Labs digital
    calculators to have some degree of general programmability, although
    neither was a fully general-purpose calculator".
    Right, and remember after the model 1, they built the model 2, 3, 4, 5,
    and two model 6's for a government military agency.
    I forget which one. I saw a couple of the later ones in operation
    sometime in the 1950s, I think. IIRC, they used normal little telephone
    relays, not crossbar switches.

    I had one of those crossbar switches when I was in college. I think it
    was a 10x20x6. I made a telephone exchange with it and a couple of other
    relays and a stepper switch to count dial pulses from my "customers."
    Jean-David Beyer, May 12, 2013
  8. Those card translators were noisy. They were electromechanical and
    dropped a subset of the cards.
    That card translator may have been the first application of
    semiconductor photocells in production in the Bell System. Light shown
    into one end was detected at the other end by semiconductor photocells
    instead of vacuum tube ones.
    Jean-David Beyer, May 12, 2013
  9. Eric you are in over your head when you start telling
    the whole world that all of the history books are wrong
    after reading, and misunderstanding, one of them.

    You are saying that today's ASIC is not a computer, just
    because you can't change the programming in the ROM.

    Pretty silly.
    Floyd L. Davidson, May 12, 2013
  10. Dale

    Eric Stevens Guest

    You are trying to argue that the No4 crossbar was a computer in the
    modern sense which predated Colossus. I might be happier to accept
    your claim if I was aware of even one book/web-site which considered
    the No4 crossbar to be a computer in the modern sense. Do you know of
    Eric Stevens, May 12, 2013
  11. Dale

    Eric Stevens Guest

    In another article I've invited you to respond with a suitable history
    No I'm not. I'm not discussing ASICs at all.
    Eric Stevens, May 12, 2013
  12. Read the cites that have already been provide. There is
    no point in going around in circles.
    Floyd L. Davidson, May 12, 2013
  13. The silly part is that you don't know what you are
    Floyd L. Davidson, May 12, 2013
  14. Dale

    Eric Stevens Guest

    --- snip ---
    Especially when they don't answer my question. All we have is your
    assertions, the first of which was:

    "A crossbar switch is a mechanical computer. In the 1940's it was
    the most advanced computer in existence."

    ... which I showed to be wrong with the quotes about the Colossus. In
    fact there is no evidence to even show that it was a computer (in the
    modern sense). I don't know how the 4A worked but the information
    provided by Jean-David Beyer makes it sound more or less like a 4 with
    a Jacquard system attached.
    Eric Stevens, May 13, 2013
  15. Dale

    Eric Stevens Guest

    We started off discussing your claim that:

    "A crossbar switch is a mechanical computer. In the
    1940's it was the most advanced computer in existence."

    ... which claim can be disproved by the citation of the Colossus.

    You then switched to:

    "We were talking about pre-WWII though.

    The No4 crossbar switch as a commercial product was
    first installed in 1943. The first prototype of the
    Colossus was demonstrated that same year."

    ... which ignored the fact which later emerged that it was not until
    1953 that the 4a (which was closer to a computer) went into service.
    Before that it was the 4 which required operator direction.

    Then you wrote:

    "The question originally raised was about pre-WWII, and my statement
    was correct up through the early 1940's. My appologies (sic) for
    not limiting it enough for you."

    That correction might be true if only you could get someone to agree
    with you that the No4 crossbar was a computer (in the modern sense)
    but you can't. All you do is evade.

    It's obvious you can't justify your assertion. Nor will you admit you
    were wrong. It's a waste of time proceeding any further with this
    Eric Stevens, May 13, 2013
  16. That may be when you first woke up and saw the discussion...
    I didn't switch the topic, but you are still trying to!
    You still haven't caught the significance of what has
    been explained to you more than once by others as well
    as myself. The No4 Crossbar switch was a computer. It
    was developed prior to WWII, along with the more generic
    computer aspects of the mechanical crossbar switching
    mechanism. Much of the research was with generic
    computing, but the No4 Crossbar tandem switch was a
    specific commercial product that was developed using
    that research.
    I'm sorry that you refuse to read and understand the
    references that have been provided to you. I don't feel
    compelled to go to any great effort to help you learn
    (I've known you for many years Eric, and have seen you
    pull this same stunt before. You aren't going to
    It has already been "justified" with external
    references. There is no point it going farther with
    that discussion.

    If you don't think a 4A Crossbar switch was a
    computer... fine. But that's a very silly stand to
    Floyd L. Davidson, May 13, 2013
  17. Dale

    Eric Stevens Guest

    --- PROVE IT ---
    But you haven't provided any. I know: I've been back and looked.

    Virtually all the references in this discussion have been provided by
    Not by you.
    You are changing the subject again. It started off with the No4 of
    1943. Now you are trying to discuss the No4a of 1953.
    Eric Stevens, May 13, 2013
  18. Dale

    Eric Stevens Guest

    The prototype of the No4 crossbar was installed in Philadelphia in
    1943. No more were built until 1948. It was at this point that the
    design was modified to eventually give rise to the No4a crossbar.
    By the time the No4 crossbar switch was a commercial product ten
    examples of the Colossus had been built and decommissioned.
    Eric Stevens, May 13, 2013
  19. Dale

    Savageduck Guest

    While you two have been engaged it the usual Floyd/Eric vortex of
    esoterica, I have been doing some snooping around of my own and I found
    the following. Make of it what you will. I am not going to join this
    debate as my computing days started long after the age of the No 4
    Crossbar or Colossus, with FORTRAN on an NCR 304. However, I will just
    toss this into the arena for you guys to tear apart.

    It seems not even Bell Labs or AT&T called the No4 Crossbar a
    "computer". Certainly one could argue that an automated telephone
    switching device could be thought of as a computer, but it seems AT&T
    didn't see it that way.
    < >
    < >

    Conversely, at the same time Colossus was undoubtably being used as a
    serious problem solving computer at Bletchley Park.
    < >
    Savageduck, May 13, 2013
  20. There were prototypes of the No4 Crossbar at least as
    far back as 1937. The switch installed in Philidelphia
    in 1943, had been in the planning stages in 1941 and was
    not a prototype, it was a production switch which was in
    commercial use for nearly four decades. A 4ESS was
    installed in Philadelphia in 1980.

    The reason the Colossus continued to be developed and
    the No4 Crossbar switch did not was simply the
    priorities required by WWII. By 1946, when Bell Labs
    was able to shift back to a peace time set of priorities
    there had been many advances in technology, and it was
    two years before they were ready to resume installation
    of Class 4 switching systems. (Note the two year lag
    from initial plan to installation that existed prior to
    the war too.)

    There is significance that the Bell System did not
    install *any* tandem trunk switches, of any kind, from
    1943 until 1948. Bell Labs had been prohibited from
    domestic use of any technology that even touched on work
    being done in the war effort.

    In 1948 the Bell System resumed building the long
    distance network, but with vast differences in
    technology. The most obvious and significant change was
    the TD-2 Microwave (almost totally a product of war time
    research, specifically the 416 planar triode vaccum
    tube), which beginning in 1948 was installed virtually
    across the US. The TD-2 microwave brought long distance
    service across the continenet that even grandma could
    hear, and of even greater significance it also provided
    transport of Television over long distances.
    Floyd L. Davidson, May 13, 2013
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