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#61
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better Kodak reorganization
Eric Stevens wrote:
On Sat, 11 May 2013 17:22:16 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Sat, 11 May 2013 04:00:15 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Fri, 10 May 2013 16:41:20 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Fri, 10 May 2013 11:14:12 -0800, (Floyd L. Davidson) wrote: "J. Clarke" wrote: In article , says... Because all switching systems from the advent of the crossbar on were in fact computers. For a very loose definition of "computer". A crossbar switch is a mechanical computer. In the 1940's it was the most advanced computer in existence. Debatable http://en.wikipedia.org/wiki/Colossus_computer We were talking about pre-WWII though. _YOU_ were talking about the 1940s. So was I. The question originally raised was about pre-WWII, and my statement was correct up through the early 1940's. My appologies for not limiting it enough for you. The No4 crossbar switch as a commercial product was first installed in 1943. The first prototype of the Colossus was demonstrated that same year. The point is that during the early development, when the first crossbar switches/computers were being produced for research purposes, there was nothing more advanced. Of course by the time the crossbar switch was a commercial product there was indeed a research computer that as should be expect was more advanced. The Colossus was far more than a research computer. People's lives were depending on it. It was just a prototype in 1943 at a time when the No4 Crossbar was a production product in commercial use. A functional working Colossus was produced in 1944 or 1945. From the URL I have already given: "The prototype, Colossus Mark 1, was shown to be working in December 1943 and was operational at Bletchley Park by 5 February 1944.[1] An improved Colossus Mark 2 first worked on 1 June 1944,[2] just in time for the Normandy Landings. Ten Colossus computers were in use by the end of the war." The history of crossbar switches is given in https://en.wikipedia.org/wiki/Crossbar_switch from which it appears that it's invention was not that of an earth-shattering device emerging from Bell labs. The duty of a No4 crossbar switch is described in http://en.wikipedia.org/wiki/Class_4_telephone_switch from which it appears the term applies not to a particular device (or device family) but to what ever 'toll switch' device might be used to connect two No5 crossbar devices. It could even be applied to a bunch of human operators. No matter what the arrangement of No4 and No5 crossbar devices may have been, they don't seem to have represented the same level of advance as the Colossus. Eric your imagination runs wild, but is not at all significant to the discussion. The No4 Crossbar is a very specific model of what is correctly described as a Class 4 switch. It was replaced by the 4A Crossbar switch. Today a "Class 4" switch would be represented by a 4ESS switch (which is not a Crossbar). What you describe as "your imagination" is in fact Wikipedia. You should write to them and connect their errors. 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. There is very little information on the Internet about the No4 Crossbar but http://www.corp.att.com/history/neth...switching.html 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 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. 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. 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. There is nothing in the above to say when the No 4 Crossbar was supplanted by the No 4A but http://tinyurl.com/cmk89j5 says: "Direct distance dialing ("DDD") started in the United States in 1953" That's a fairly specific statement which sounds like it refers to the introduction of the No4a 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. You are still missing the point. The discussion was whether AT&T made computers pre-WWII. Since they had a production Crossbar switch in 1943 there can be little doubt that Bell Labs was working with computers prior to the war. The fact is that going into the 1940's a crossbar mechanical computer was as advanced at it got. And Jean-David Beyer has cited references to the specific R&D crossbar computer projects that preceeded production of the No4 Crossbar. End of the story... 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 devices. -- Floyd L. Davidson http://www.apaflo.com/ Ukpeagvik (Barrow, Alaska) |
#62
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better Kodak reorganization
Eric Stevens wrote:
On Sat, 11 May 2013 19:36:33 -0400, Jean-David Beyer wrote: On 05/11/2013 07:09 PM, Eric Stevens wrote: On Sat, 11 May 2013 04:00:15 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Fri, 10 May 2013 16:41:20 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Fri, 10 May 2013 11:14:12 -0800, (Floyd L. Davidson) wrote: "J. Clarke" wrote: In article , says... Because all switching systems from the advent of the crossbar on were in fact computers. For a very loose definition of "computer". A crossbar switch is a mechanical computer. In the 1940's it was the most advanced computer in existence. Debatable http://en.wikipedia.org/wiki/Colossus_computer We were talking about pre-WWII though. _YOU_ were talking about the 1940s. So was I. The question originally raised was about pre-WWII, and my statement was correct up through the early 1940's. My appologies for not limiting it enough for you. The No4 crossbar switch as a commercial product was first installed in 1943. The first prototype of the Colossus was demonstrated that same year. The point is that during the early development, when the first crossbar switches/computers were being produced for research purposes, there was nothing more advanced. Of course by the time the crossbar switch was a commercial product there was indeed a research computer that as should be expect was more advanced. The Colossus was far more than a research computer. People's lives were depending on it. It was just a prototype in 1943 at a time when the No4 Crossbar was a production product in commercial use. A functional working Colossus was produced in 1944 or 1945. From the URL I have already given: "The prototype, Colossus Mark 1, was shown to be working in December 1943 and was operational at Bletchley Park by 5 February 1944.[1] An improved Colossus Mark 2 first worked on 1 June 1944,[2] just in time for the Normandy Landings. Ten Colossus computers were in use by the end of the war." The history of crossbar switches is given in https://en.wikipedia.org/wiki/Crossbar_switch from which it appears that it's invention was not that of an earth-shattering device emerging from Bell labs. The duty of a No4 crossbar switch is described in http://en.wikipedia.org/wiki/Class_4_telephone_switch from which it appears the term applies not to a particular device (or device family) but to what ever 'toll switch' device might be used to connect two No5 crossbar devices. It could even be applied to a bunch of human operators. No matter what the arrangement of No4 and No5 crossbar devices may have been, they don't seem to have represented the same level of advance as the Colossus. Bear in mind that the Bell Labs Model 1 relay computer was in use before the Colossus. "The company agreed to finance construction of a large experimental model of Stibitz's invention. Stibitz completed the designs in February, 1938, and the construction of the machine began in April, 1939, by Samuel Williams, a switching engineer in Bell. The final product was ready in October and was first put into operation on January 8, 1940, and remained in service until 1949." http://history-computer.com/ModernCo...s/Stibitz.html 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". Be careful with semantics. There is a reason everyone calls those devices computers, even though they were not "programmable". 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 http://www.apaflo.com/ Ukpeagvik (Barrow, Alaska) |
#64
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better Kodak reorganization
Eric Stevens wrote:
On Sat, 11 May 2013 22:45:32 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Sat, 11 May 2013 19:36:33 -0400, Jean-David Beyer wrote: On 05/11/2013 07:09 PM, Eric Stevens wrote: On Sat, 11 May 2013 04:00:15 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Fri, 10 May 2013 16:41:20 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Fri, 10 May 2013 11:14:12 -0800, (Floyd L. Davidson) wrote: "J. Clarke" wrote: In article , says... Because all switching systems from the advent of the crossbar on were in fact computers. For a very loose definition of "computer". A crossbar switch is a mechanical computer. In the 1940's it was the most advanced computer in existence. Debatable http://en.wikipedia.org/wiki/Colossus_computer We were talking about pre-WWII though. _YOU_ were talking about the 1940s. So was I. The question originally raised was about pre-WWII, and my statement was correct up through the early 1940's. My appologies for not limiting it enough for you. The No4 crossbar switch as a commercial product was first installed in 1943. The first prototype of the Colossus was demonstrated that same year. The point is that during the early development, when the first crossbar switches/computers were being produced for research purposes, there was nothing more advanced. Of course by the time the crossbar switch was a commercial product there was indeed a research computer that as should be expect was more advanced. The Colossus was far more than a research computer. People's lives were depending on it. It was just a prototype in 1943 at a time when the No4 Crossbar was a production product in commercial use. A functional working Colossus was produced in 1944 or 1945. From the URL I have already given: "The prototype, Colossus Mark 1, was shown to be working in December 1943 and was operational at Bletchley Park by 5 February 1944.[1] An improved Colossus Mark 2 first worked on 1 June 1944,[2] just in time for the Normandy Landings. Ten Colossus computers were in use by the end of the war." The history of crossbar switches is given in https://en.wikipedia.org/wiki/Crossbar_switch from which it appears that it's invention was not that of an earth-shattering device emerging from Bell labs. The duty of a No4 crossbar switch is described in http://en.wikipedia.org/wiki/Class_4_telephone_switch from which it appears the term applies not to a particular device (or device family) but to what ever 'toll switch' device might be used to connect two No5 crossbar devices. It could even be applied to a bunch of human operators. No matter what the arrangement of No4 and No5 crossbar devices may have been, they don't seem to have represented the same level of advance as the Colossus. Bear in mind that the Bell Labs Model 1 relay computer was in use before the Colossus. "The company agreed to finance construction of a large experimental model of Stibitz's invention. Stibitz completed the designs in February, 1938, and the construction of the machine began in April, 1939, by Samuel Williams, a switching engineer in Bell. The final product was ready in October and was first put into operation on January 8, 1940, and remained in service until 1949." http://history-computer.com/ModernCo...s/Stibitz.html 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". Be careful with semantics. There is a reason everyone calls those devices computers, even though they were not "programmable". 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 Colossus. They weren't "programmable" in the sense we use today, mostly because Bell Labs did not invent that concept until later! 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). But they did have a hard wired program, So does the lighting in my house. 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. So they didn't have a stored program. You don't read well, do you. -- Floyd L. Davidson http://www.apaflo.com/ Ukpeagvik (Barrow, Alaska) |
#65
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better Kodak reorganization
On Sat, 11 May 2013 22:40:12 -0800, (Floyd L.
Davidson) wrote: Eric Stevens wrote: On Sat, 11 May 2013 17:22:16 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Sat, 11 May 2013 04:00:15 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Fri, 10 May 2013 16:41:20 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Fri, 10 May 2013 11:14:12 -0800, (Floyd L. Davidson) wrote: "J. Clarke" wrote: In article , says... Because all switching systems from the advent of the crossbar on were in fact computers. For a very loose definition of "computer". A crossbar switch is a mechanical computer. In the 1940's it was the most advanced computer in existence. Debatable http://en.wikipedia.org/wiki/Colossus_computer We were talking about pre-WWII though. _YOU_ were talking about the 1940s. So was I. The question originally raised was about pre-WWII, and my statement was correct up through the early 1940's. My appologies for not limiting it enough for you. The No4 crossbar switch as a commercial product was first installed in 1943. The first prototype of the Colossus was demonstrated that same year. The point is that during the early development, when the first crossbar switches/computers were being produced for research purposes, there was nothing more advanced. Of course by the time the crossbar switch was a commercial product there was indeed a research computer that as should be expect was more advanced. The Colossus was far more than a research computer. People's lives were depending on it. It was just a prototype in 1943 at a time when the No4 Crossbar was a production product in commercial use. A functional working Colossus was produced in 1944 or 1945. From the URL I have already given: "The prototype, Colossus Mark 1, was shown to be working in December 1943 and was operational at Bletchley Park by 5 February 1944.[1] An improved Colossus Mark 2 first worked on 1 June 1944,[2] just in time for the Normandy Landings. Ten Colossus computers were in use by the end of the war." The history of crossbar switches is given in https://en.wikipedia.org/wiki/Crossbar_switch from which it appears that it's invention was not that of an earth-shattering device emerging from Bell labs. The duty of a No4 crossbar switch is described in http://en.wikipedia.org/wiki/Class_4_telephone_switch from which it appears the term applies not to a particular device (or device family) but to what ever 'toll switch' device might be used to connect two No5 crossbar devices. It could even be applied to a bunch of human operators. No matter what the arrangement of No4 and No5 crossbar devices may have been, they don't seem to have represented the same level of advance as the Colossus. Eric your imagination runs wild, but is not at all significant to the discussion. The No4 Crossbar is a very specific model of what is correctly described as a Class 4 switch. It was replaced by the 4A Crossbar switch. Today a "Class 4" switch would be represented by a 4ESS switch (which is not a Crossbar). What you describe as "your imagination" is in fact Wikipedia. You should write to them and connect their errors. 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. There is very little information on the Internet about the No4 Crossbar but http://www.corp.att.com/history/neth...switching.html 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 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. Bull**** to it being a computer. It responded to the operator's dialer in the same way the No5 crossbar devices responded to the callers dialer. 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. 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. 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. In exactly the same way the lighting in my house operates via a stored program if switches are operated and wires are rerouted. 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. There is nothing in the above to say when the No 4 Crossbar was supplanted by the No 4A but http://tinyurl.com/cmk89j5 says: "Direct distance dialing ("DDD") started in the United States in 1953" That's a fairly specific statement which sounds like it refers to the introduction of the No4a 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. You are still missing the point. The discussion was whether AT&T made computers pre-WWII. Since they had a production Crossbar switch in 1943 there can be little doubt that Bell Labs was working with computers prior to the war. The fact is that going into the 1940's a crossbar mechanical computer was as advanced at it got. And Jean-David Beyer has cited references to the specific R&D crossbar computer projects that preceeded production of the No4 Crossbar. End of the story... Try reading and understanding the two quoted paragraphs above. Your digression into minute trivia ... Haw! ... 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 devices. -- Regards, Eric Stevens |
#66
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better Kodak reorganization
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". Be careful with semantics. There is a reason everyone calls those devices computers, even though they were not "programmable". 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. 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." |
#67
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better Kodak reorganization
On 05/12/2013 02:40 AM, Floyd L. Davidson wrote:
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. 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. |
#68
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better Kodak reorganization
Eric Stevens wrote:
On Sat, 11 May 2013 22:40:12 -0800, (Floyd L. Davidson) wrote: 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. Bull**** to it being a computer. It responded to the operator's dialer in the same way the No5 crossbar devices responded to the callers dialer. 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. .... 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. In exactly the same way the lighting in my house operates via a stored program if switches are operated and wires are rerouted. 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 http://www.apaflo.com/ Ukpeagvik (Barrow, Alaska) |
#69
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better Kodak reorganization
On Sun, 12 May 2013 01:26:39 -0800, (Floyd L.
Davidson) wrote: Eric Stevens wrote: On Sat, 11 May 2013 22:45:32 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Sat, 11 May 2013 19:36:33 -0400, Jean-David Beyer wrote: On 05/11/2013 07:09 PM, Eric Stevens wrote: On Sat, 11 May 2013 04:00:15 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Fri, 10 May 2013 16:41:20 -0800, (Floyd L. Davidson) wrote: Eric Stevens wrote: On Fri, 10 May 2013 11:14:12 -0800, (Floyd L. Davidson) wrote: "J. Clarke" wrote: In article , says... Because all switching systems from the advent of the crossbar on were in fact computers. For a very loose definition of "computer". A crossbar switch is a mechanical computer. In the 1940's it was the most advanced computer in existence. Debatable http://en.wikipedia.org/wiki/Colossus_computer We were talking about pre-WWII though. _YOU_ were talking about the 1940s. So was I. The question originally raised was about pre-WWII, and my statement was correct up through the early 1940's. My appologies for not limiting it enough for you. The No4 crossbar switch as a commercial product was first installed in 1943. The first prototype of the Colossus was demonstrated that same year. The point is that during the early development, when the first crossbar switches/computers were being produced for research purposes, there was nothing more advanced. Of course by the time the crossbar switch was a commercial product there was indeed a research computer that as should be expect was more advanced. The Colossus was far more than a research computer. People's lives were depending on it. It was just a prototype in 1943 at a time when the No4 Crossbar was a production product in commercial use. A functional working Colossus was produced in 1944 or 1945. From the URL I have already given: "The prototype, Colossus Mark 1, was shown to be working in December 1943 and was operational at Bletchley Park by 5 February 1944.[1] An improved Colossus Mark 2 first worked on 1 June 1944,[2] just in time for the Normandy Landings. Ten Colossus computers were in use by the end of the war." The history of crossbar switches is given in https://en.wikipedia.org/wiki/Crossbar_switch from which it appears that it's invention was not that of an earth-shattering device emerging from Bell labs. The duty of a No4 crossbar switch is described in http://en.wikipedia.org/wiki/Class_4_telephone_switch from which it appears the term applies not to a particular device (or device family) but to what ever 'toll switch' device might be used to connect two No5 crossbar devices. It could even be applied to a bunch of human operators. No matter what the arrangement of No4 and No5 crossbar devices may have been, they don't seem to have represented the same level of advance as the Colossus. Bear in mind that the Bell Labs Model 1 relay computer was in use before the Colossus. "The company agreed to finance construction of a large experimental model of Stibitz's invention. Stibitz completed the designs in February, 1938, and the construction of the machine began in April, 1939, by Samuel Williams, a switching engineer in Bell. The final product was ready in October and was first put into operation on January 8, 1940, and remained in service until 1949." http://history-computer.com/ModernCo...s/Stibitz.html 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". Be careful with semantics. There is a reason everyone calls those devices computers, even though they were not "programmable". 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 Colossus. They weren't "programmable" in the sense we use today, mostly because Bell Labs did not invent that concept until later! 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). But they did have a hard wired program, So does the lighting in my house. 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. So they didn't have a stored program. You don't read well, do you. 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 one? -- Regards, Eric Stevens |
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better Kodak reorganization
On Sun, 12 May 2013 12:21:49 -0800, (Floyd L.
Davidson) wrote: Eric Stevens wrote: On Sat, 11 May 2013 22:40:12 -0800, (Floyd L. Davidson) wrote: 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. Bull**** to it being a computer. It responded to the operator's dialer in the same way the No5 crossbar devices responded to the callers dialer. 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. In another article I've invited you to respond with a suitable history book. ... 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. In exactly the same way the lighting in my house operates via a stored program if switches are operated and wires are rerouted. You are saying that today's ASIC is not a computer, just because you can't change the programming in the ROM. No I'm not. I'm not discussing ASICs at all. Pretty silly. -- Regards, Eric Stevens |
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