The discussion below concluded in late November, but I have some comments and considerations. First, I'll say that there's any number of explanations available, for the history of computing technology and use. The person or institution doing the explaining, has their own objectives. The item has its time and place, and has levels of technology in it. And, there's sometimes consideration of the audience (child, expert in X but not Y, etc.). So - no right and singular answers to questions of presentation. I'll give or support a view for my own reasons. Jeffrey Brace via vcf-midatlantic wrote:
How would you explain the George Philbrick machine to an 8 year old?
Well, as you know it's critically important to tune your presentation to the level of the guest. When starting a more personal tour of LSSM, we usually find a non-intrusive way, starting out with reading body language etc, to ask a person what their levels of technical knowledge and interest are. Then we explain things in different ways, on different levels, based on that.
For a total technical neophyte, our explanations are more geared toward talking about how what we have now (holding up my smartphone) wouldn't exist without having first passed through all of these (gesturing toward the exhibit floor) phases of development, then go to some specific stories as to how and why.
For an EE or CS person with a background in electronics and/or processor architecture, that's a waste of time. We go into things like "this machine is a 12-bit system implemented using all 7400-series TTL chips" when I fire up the PDP-8/e. I talk about "no chips at all, all discrete transistor logic" when we walk past the table of Straight-8s.
While the LSSM doesn't have anything like the Philbrick system, we do have a Heath H-1, another late-1950s tube-based analog computer. To a young person, we'd explain that it was used by scientists and engineers to perform calculations for designing planes and big buildings. It's complicated, look at all those knobs!
But to an EE/CS person who maybe doesn't know about analog computers (most haven't), we explain that it's a system with no bits, just voltages representing physical quantities, and most importantly it's not a discrete system, but a continuous system. These operational amplifiers (gesturing toward the op-amps) and resistors can be wired up to perform most any mathematical primitive, and wired together with capacitors to perform integration and differentiation, to solve the differential equations that most every real-world process is based on.
How do you explain what a vacuum tube actually does to an 8 year old?
I wouldn't, as there's essentially no chance that he/she would be interested or have the background to be able to understand it. See above. ;) -- Dave McGuire, AK4HZ New Kensington, PA
I have to agree with earlier posts by David Gesswein, who stressed the point that analog computers solve "differential equations". And all have mentioned in various ways, that analog computers use voltage-levels, not "bits", to represent the values computed. Those are fundamental considerations from my view. Other people have other views, I won't argue much with them - I'm arguing with people who are still choosing what views to consider. My view is, as a BSEE educated in the 1970's about both analog and digital circuits, who saw analog computers in use in academia and in the factory, who worked on one or two of them in my working lifetime. The hardest thing about explaining analog computing, is that it's almost TOTALLY EXTINCT today. It's hard to think or talk about something, outside your experiences. And preservation of extinct computing - and explaining it in it's own context - matters to me. One can explain "voltages not bits", in any number of ways, appropriate to audiences and settings. "Temperature" might be a good example. There's still mercury thermometers, mechanical thermostats and mechanical thermometers. They use the expansion of metals in an ANALOG way, to represent "temperature". The Weather Channel, gives it some number. But we feel "hot" or "cold" without numbers in our heads. A point to consider: the physical world is not lists of numbers, it's events and materials and the flow of time. "Differential equations" is jargon used by engineers and scientists. But it comes down to actions in systems over time. How fast does water boil on the stove? Or freeze if put outside in the winter? How long does it take your car to go from zero to 60? How long does it take a baseball/football in flight to be caught? These are ANALOG values that change with time. And, there are analog circuits (components wired up) which can represent these rates-of-change calculations. Then you feed those circuits the analog values as voltages, and watch what they do over TIME. *That* is what an analog computer is about. Circuits and components, wired for one computation, using time and voltages to represent values - no "bits", no digital (except for numeric results or inputs). I myself, don't tell people "this is too complicated to explain". I give them *something*; it will provide some impression and place to start; further consideration will be their choice to make. So. I hope the two explanations above, of "voltages not bits" and "differential equations", are helpful. I hope the notion of "extinct computer preservation" gets some attention. Otherwise, I'm not going to debate some ultimate description or how-to-talk-to methods. I've explained why, and I've offered my own views. Herb Johnson retrotechnology.com PS: a vacuum tube, controls electrons going from a hot metal to a metal plate. The flow of electrons is a current, like water from a faucet. The current is controlled by the electrons going through a grid. a grid is wires strung across the current-flow, which repel the electrons like magnets do. Just as you can control water by turning a faucet, you can control electric currents with a vacuum tube, by changing voltages on its grid. Old radios and TV's, very old computers, used vacuum tubes. -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net
This may be one of the clearest explanations of analog commuting I've heard; and I'm going to steal it while docenting :-) Thanks, Herb! On Mon, Dec 4, 2017 at 12:18 PM Herb Johnson via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
The discussion below concluded in late November, but I have some comments and considerations.
First, I'll say that there's any number of explanations available, for the history of computing technology and use. The person or institution doing the explaining, has their own objectives. The item has its time and place, and has levels of technology in it. And, there's sometimes consideration of the audience (child, expert in X but not Y, etc.).
So - no right and singular answers to questions of presentation. I'll give or support a view for my own reasons.
Jeffrey Brace via vcf-midatlantic wrote:
How would you explain the George Philbrick machine to an 8 year old?
Well, as you know it's critically important to tune your presentation to the level of the guest. When starting a more personal tour of LSSM, we usually find a non-intrusive way, starting out with reading body language etc, to ask a person what their levels of technical knowledge and interest are. Then we explain things in different ways, on different levels, based on that.
For a total technical neophyte, our explanations are more geared toward talking about how what we have now (holding up my smartphone) wouldn't exist without having first passed through all of these (gesturing toward the exhibit floor) phases of development, then go to some specific stories as to how and why.
For an EE or CS person with a background in electronics and/or processor architecture, that's a waste of time. We go into things like "this machine is a 12-bit system implemented using all 7400-series TTL chips" when I fire up the PDP-8/e. I talk about "no chips at all, all discrete transistor logic" when we walk past the table of Straight-8s.
While the LSSM doesn't have anything like the Philbrick system, we do have a Heath H-1, another late-1950s tube-based analog computer. To a young person, we'd explain that it was used by scientists and engineers to perform calculations for designing planes and big buildings. It's complicated, look at all those knobs!
But to an EE/CS person who maybe doesn't know about analog computers (most haven't), we explain that it's a system with no bits, just voltages representing physical quantities, and most importantly it's not a discrete system, but a continuous system. These operational amplifiers (gesturing toward the op-amps) and resistors can be wired up to perform most any mathematical primitive, and wired together with capacitors to perform integration and differentiation, to solve the differential equations that most every real-world process is based on.
How do you explain what a vacuum tube actually does to an 8 year old?
I wouldn't, as there's essentially no chance that he/she would be interested or have the background to be able to understand it. See above. ;) -- Dave McGuire, AK4HZ New Kensington, PA
I have to agree with earlier posts by David Gesswein, who stressed the point that analog computers solve "differential equations". And all have mentioned in various ways, that analog computers use voltage-levels, not "bits", to represent the values computed. Those are fundamental considerations from my view. Other people have other views, I won't argue much with them - I'm arguing with people who are still choosing what views to consider.
My view is, as a BSEE educated in the 1970's about both analog and digital circuits, who saw analog computers in use in academia and in the factory, who worked on one or two of them in my working lifetime. The hardest thing about explaining analog computing, is that it's almost TOTALLY EXTINCT today. It's hard to think or talk about something, outside your experiences. And preservation of extinct computing - and explaining it in it's own context - matters to me.
One can explain "voltages not bits", in any number of ways, appropriate to audiences and settings. "Temperature" might be a good example. There's still mercury thermometers, mechanical thermostats and mechanical thermometers. They use the expansion of metals in an ANALOG way, to represent "temperature". The Weather Channel, gives it some number. But we feel "hot" or "cold" without numbers in our heads. A point to consider: the physical world is not lists of numbers, it's events and materials and the flow of time.
"Differential equations" is jargon used by engineers and scientists. But it comes down to actions in systems over time. How fast does water boil on the stove? Or freeze if put outside in the winter? How long does it take your car to go from zero to 60? How long does it take a baseball/football in flight to be caught? These are ANALOG values that change with time. And, there are analog circuits (components wired up) which can represent these rates-of-change calculations. Then you feed those circuits the analog values as voltages, and watch what they do over TIME. *That* is what an analog computer is about. Circuits and components, wired for one computation, using time and voltages to represent values - no "bits", no digital (except for numeric results or inputs).
I myself, don't tell people "this is too complicated to explain". I give them *something*; it will provide some impression and place to start; further consideration will be their choice to make.
So. I hope the two explanations above, of "voltages not bits" and "differential equations", are helpful. I hope the notion of "extinct computer preservation" gets some attention. Otherwise, I'm not going to debate some ultimate description or how-to-talk-to methods. I've explained why, and I've offered my own views.
Herb Johnson retrotechnology.com
PS: a vacuum tube, controls electrons going from a hot metal to a metal plate. The flow of electrons is a current, like water from a faucet. The current is controlled by the electrons going through a grid. a grid is wires strung across the current-flow, which repel the electrons like magnets do. Just as you can control water by turning a faucet, you can control electric currents with a vacuum tube, by changing voltages on its grid. Old radios and TV's, very old computers, used vacuum tubes.
-- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net
<snip>
PS: a vacuum tube, controls electrons going from a hot metal to a metal plate. The flow of electrons is a current, like water from a faucet. The current is controlled by the electrons going through a grid. a grid is wires strung across the current-flow, which repel the electrons like magnets do. Just as you can control water by turning a faucet, you can control electric currents with a vacuum tube, by changing voltages on its grid. Old radios and TV's, very old computers, used vacuum tubes.
--
One notable exception - Many of the best new production guitar and bass amps still use tubes. It's not a nostalgia thing, they often sound better and there is a market for the "tube sound" because solid state amps can't seem to reproduce it. I use both tube and solid state amplifiers. Many have tubes as pre-amps, there are also guitar pedals with tubes in them, same purpose. They warm up the sound before the post-gain power amplifier pushes the sound signal to the speakers. Bill
On Mon, Dec 4, 2017 at 1:41 PM, william degnan via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
<snip>
PS: a vacuum tube, controls electrons going from a hot metal to a metal plate. The flow of electrons is a current, like water from a faucet.
The
current is controlled by the electrons going through a grid. a grid is wires strung across the current-flow, which repel the electrons like magnets do. Just as you can control water by turning a faucet, you can control electric currents with a vacuum tube, by changing voltages on its grid. Old radios and TV's, very old computers, used vacuum tubes.
--
One notable exception - Many of the best new production guitar and bass amps still use tubes. It's not a nostalgia thing, they often sound better and there is a market for the "tube sound" because solid state amps can't seem to reproduce it. I use both tube and solid state amplifiers. Many have tubes as pre-amps, there are also guitar pedals with tubes in them, same purpose. They warm up the sound before the post-gain power amplifier pushes the sound signal to the speakers.
Bill
Bill, The big reason that tube sound still has a strong following in the music industry has to do with the characteristics of the components. The vacuum tube has a natural characteristic in the audio spectrum to produce even harmonics which is soothing to the human ear. While solid-state amplifiers have a natural characteristics to produce odd harmonics - which isn't very pleasing. This is before you run any guitar through some sort of effects unit. That feature doesn't apply to analog computers. But it does apply to digital vacuum tube computers. The main reason CPU speeds couldn't reach beyond 500khz or more is because they were still using linear vacuum tubes in the beginning. Even though they had a large frequency bandwidth, this was a linear measurement [ie. sinusoidal waves as in a transmitter - not square waves as in a computer]. In general, square waves in a computer have odd harmonics, and so you needed even a larger bandwidth for vacuum tubes. This is because the circuit needs enough energy to output the main frequency plus the odd harmonics without the signal getting distorted and not resemble a square wave anymore. Another component characteristic which impeded this bandwidth is called the Miller Effect, excessive internal capacitance of the component limited it's bandwidth. Which is why they innovated a new form of vacuum tube in the mid-50's called computer-grade tubes which contained a larger frequency bandwidth for square waves - ie higher switching speeds. This would have pushed the envelope so to speak on next generation vacuum tube computers. I saved old vacuum tube computing books with examples running at 1mhz and 2mhz. But then look what else happened back then. Transistors came into our world - much smaller and less power - not much faster at first. But it didn't take long before they were running a 1mhz and more in the digital realm - the same reasons from before applied regarding the linear bandwidth. Dan
My view is, as a BSEE educated in the 1970's about both analog and digital circuits, who saw analog computers in use in academia and in the factory, who worked on one or two of them in my working lifetime. The hardest thing about explaining analog computing, is that it's almost TOTALLY EXTINCT today. It's hard to think or talk about something, outside your experiences. And preservation of extinct computing - and explaining it in it's own context - matters to me.
One can explain "voltages not bits", in any number of ways, appropriate to audiences and settings. "Temperature" might be a good example. There's still mercury thermometers, mechanical thermostats and mechanical thermometers. They use the expansion of metals in an ANALOG way, to represent "temperature". The Weather Channel, gives it some number. But we feel "hot" or "cold" without numbers in our heads. A point to consider: the physical world is not lists of numbers, it's events and materials and the flow of time.
"Differential equations" is jargon used by engineers and scientists. But it comes down to actions in systems over time. How fast does water boil on the stove? Or freeze if put outside in the winter? How long does it take your car to go from zero to 60? How long does it take a baseball/football in flight to be caught? These are ANALOG values that change with time. And, there are analog circuits (components wired up) which can represent these rates-of-change calculations. Then you feed those circuits the analog values as voltages, and watch what they do over TIME.*That* is what an analog computer is about. Circuits and components, wired for one computation, using time and voltages to represent values - no "bits", no digital (except for numeric results or inputs).
I myself, don't tell people "this is too complicated to explain". I give them*something*; it will provide some impression and place to start; further consideration will be their choice to make.
So. I hope the two explanations above, of "voltages not bits" and "differential equations", are helpful. I hope the notion of "extinct computer preservation" gets some attention. Otherwise, I'm not going to debate some ultimate description or how-to-talk-to methods. I've explained why, and I've offered my own views.
Excellent answer. Thanks Herb. I'll throw in another example: volume knobs. Many (most?) car stereos still have knobs you turn to adjust the volume. It may be easy to tell a kid that's analog -- a directly relationship between mechanical movement of the knob vs. increase/decrease of the volume. Whereas if you use a software control to adjust the volume, even if it the interface is a slider or knob, that's digital.
On Mon, Dec 04, 2017 at 01:56:40PM -0500, Evan Koblentz via vcf-midatlantic wrote:
I'll throw in another example: volume knobs. Many (most?) car stereos still have knobs you turn to adjust the volume.
They may no longer be analog. My wifes car volume control knob seems to change in discrete steps so we have the choice of a little too soft or a little too loud due to the step size. Still a reasonble example even if there are counter examples.
On 12/04/2017 06:34 PM, David Gesswein via vcf-midatlantic wrote:
I'll throw in another example: volume knobs. Many (most?) car stereos still have knobs you turn to adjust the volume.
They may no longer be analog. My wifes car volume control knob seems to change in discrete steps so we have the choice of a little too soft or a little too loud due to the step size.
They haven't been analog for a very long time. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
I'll throw in another example: volume knobs. Many (most?) car stereos still have knobs you turn to adjust the volume.
They may no longer be analog. My wifes car volume control knob seems to change in discrete steps so we have the choice of a little too soft or a little too loud due to the step size. They haven't been analog for a very long time.
Zoinks! Foiled again!
On Mon, Dec 4, 2017 at 10:34 PM, Dave McGuire via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
On 12/04/2017 06:34 PM, David Gesswein via vcf-midatlantic wrote:
I'll throw in another example: volume knobs. Many (most?) car stereos still have knobs you turn to adjust the volume.
They may no longer be analog. My wifes car volume control knob seems to change in discrete steps so we have the choice of a little too soft or a little too loud due to the step size.
They haven't been analog for a very long time.
-Dave
-- Dave McGuire, AK4HZ New Kensington, PA
just like cell phones make a click and flash sound for old-times' sake. I find it kind of funny that at press conferences you hear all of this simulated flash and click sounds when people take photos. Kind of stupid if you ask me, but its the ones taking the photos without the click and flash that you have to worry about I guess. Bill
On 12/04/2017 12:09 PM, Herb Johnson via vcf-midatlantic wrote:
The discussion below concluded in late November, but I have some comments and considerations.
I myself, don't tell people "this is too complicated to explain". I give them *something*; it will provide some impression and place to start; further consideration will be their choice to make.
I have told people this is too complicated for me to explain ... because I don't understand it well enough to explain it. My wife doesn't appreciate when I explain in too much detail when I do know it so I try to adjust explanations to the person's background and temperament. I'm not always successful as sometimes my sarcasm gets the best of me and I say the perfect thing at exactly the wrong time. I do try to supply some answer when I have an idea, a guess when I can make a guess (making it clear that it's a guess) and I've started saying that I have no idea when I have no idea. -- Linux Home Automation Neil Cherry ncherry@linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies
I have told people this is too complicated for me to explain ... because I don't understand it well enough to explain it. My wife doesn't appreciate when I explain in too much detail when I do know it so I try to adjust explanations to the person's background and temperament. I'm not always successful as sometimes my sarcasm gets the best of me and I say the perfect thing at exactly the wrong time.
I do try to supply some answer when I have an idea, a guess when I can make a guess (making it clear that it's a guess) and I've started saying that I have no idea when I have no idea.
The most important thing (especially for our museum docents) is that we always * try * to explain and never look down on guests. Hopefully we get it mostly accurate, too.
On 12/04/2017 02:35 PM, Evan Koblentz via vcf-midatlantic wrote:
I have told people this is too complicated for me to explain ... because I don't understand it well enough to explain it. My wife doesn't appreciate when I explain in too much detail when I do know it so I try to adjust explanations to the person's background and temperament. I'm not always successful as sometimes my sarcasm gets the best of me and I say the perfect thing at exactly the wrong time.
I do try to supply some answer when I have an idea, a guess when I can make a guess (making it clear that it's a guess) and I've started saying that I have no idea when I have no idea.
The most important thing (especially for our museum docents) is that we always * try * to explain and never look down on guests. Hopefully we get it mostly accurate, too.
I wrote a book (as did Even) and I have a friend who likes to bust me about it. So I tend to joke about it a bit (it's really hard work). I had a joke I used to use on bike rides I lead: Any idiot can write a book just look at Snooki from the Jersey Shore. The joke failed every time because many of my riders had no idea what a Snooki was and they tended to be PhDs from the local Universities. Each with a book. So now I've learned, I'm not that smarter than Snooki. ;-) -- Linux Home Automation Neil Cherry ncherry@linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies
On Mon, Dec 04, 2017 at 02:31:25PM -0500, Neil Cherry via vcf-midatlantic wrote:
I do try to supply some answer when I have an idea, a guess when I can make a guess (making it clear that it's a guess) and I've started saying that I have no idea when I have no idea.
Researching the answers to questions that come up often enough is something the wider group could help with if there are more question that occur often enough.
Neil Cherry
Would analog computers have be used in control systems where feed back would be used?
Possibly. Generally analog computers in "physical plants" would be used to simulate the plant's operation. For instance, an oil refinery. The computer would not control the plant, but various controls and valves might be adjusted based on the model's response, when set-up to model the production of some chemical or distillation product. Most analog computers solve the same problem over and over again, to produce an oscillograph or paper-graph - not for real-time operations. Real-time may run faster or slower than the simulation. But, some labs (psychology labs testing human or animal responses) might use an analog computer to perform the test and record results. Herb -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net preserve, recover, restore 1970's computing email: hjohnson AT retrotechnology DOT com or try later herbjohnson AT retrotechnology DOT info
participants (8)
-
Dan Roganti -
Dave McGuire -
David Gesswein -
Dean Notarnicola -
Evan Koblentz -
Herb Johnson -
Neil Cherry -
william degnan