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  • - The Saturn V rocket took humans to the moon

  • for the first time, but the humans didn't steer the rocket.

  • It steered itself using a computer.

  • - [Man] Tower, clear.

  • - [Man] Gotta roll program.

  • - A lot of the Saturn V rocket was built here

  • in Huntsville, Alabama, otherwise known as Rocket City.

  • And one of the really cool things about living here

  • is it's filled with aerospace and computer engineers

  • who love this stuff, so a thing you can actually do here

  • is pick up the phone and call one of your friends

  • and have them call their friend, and before you know it,

  • you're in a parking lot, receiving a Saturn V

  • memory module from a guy you just met,

  • and he just trusts that you're gonna give it back to him.

  • This is 14 kilobytes of data, which is really interesting

  • because the same day I got this,

  • I had Linus Sebastian from Linus Tech Tips here.

  • We were installing a server that was over 100 terabytes.

  • Now, millions of people look to Linus

  • to understand more about modern computing hardware,

  • so I thought a really cool thing to do

  • would be stop what we were doing with the server

  • and take a closer look at this memory module

  • and how it works.

  • Let's sit back and watch a modern computer nerd

  • learn about the cutting edge technology from the 1960s.

  • I'm Destin, let's go get smarter every day.

  • - [Destin] Have you ever seen a Saturn V rocket?

  • - [Linus] No.

  • - [Destin] Okay, do you know what the Saturn V is?

  • - [Linus] Yes.

  • - [Destin] My daily life literally revolves

  • around the Saturn V.

  • Like, that's the Saturn V peeking out

  • over the trees right there.

  • - [Linus] Oh, there it is.

  • Hello.

  • - [Destin] In the 60s, they had just started building

  • digital computers, and I'm gonna show you the computer

  • that they used to steer that thing.

  • - [Linus] I mean, it's gotta be a bit

  • of a terrifying experience having, like,

  • the equivalent of a very large bomb

  • strapped to your butt.

  • - So this is the brain for the Saturn V rocket.

  • If you look up right here, this is the instrumentation ring,

  • and so they had computers on here that were digital.

  • This right here is the launch vehicle digital computer.

  • That is it.

  • This right here is a memory module, okay?

  • And if you look really, really, really close,

  • really close, you see those little bitty rings?

  • - Yeah.

  • - [Destin] OK, look right here.

  • Look at that.

  • Do you see that?

  • - [Linus] Holy smokes, so they're,

  • it looks like zip ties on chicken wire.

  • - [Destin] Okay, those are bits.

  • Those are physical bits.

  • So you see that screen?

  • - [Linus] Yeah.

  • - [Destin] These are wires that go down

  • to these boards right here, right?

  • - [Linus] Yeah.

  • - [Destin] On each node, you have an iron ring,

  • and depending on how the iron ring is magnetized,

  • that's a one or a zero.

  • That's how they programmed this computer.

  • Seriously.

  • So look at this right here.

  • - So by hand.

  • - [Destin] By hand, yes.

  • - They threaded these wires through the,

  • I mean, who has a steady, I don't even think

  • you can build one of these today if you wanted to.

  • That's incredible.

  • - [Destin] So there's a guy that worked on this

  • in the 60s here.

  • His name is Luke.

  • - Yeah.

  • - [Destin] And, you get ask him all of these questions.

  • - Fantastic.

  • - I'm Luke Talley, and at this time in 1969

  • I was a senior associate engineer at IBM in Huntsville.

  • - [Destin] So your computer pointed the rocket?

  • - That's right.

  • - [Destin] Awesome.

  • - We steered the rocket.

  • So that's a memory module.

  • - [Destin] That's a whole memory module, yeah.

  • - You musta shot somebody to get that.

  • - [Destin] So how valuable would you say that is?

  • - Well, now this, ah, I don't, I'd have no idea.

  • You have to go to Antique Roadshow.

  • This computer controls all the timing.

  • Start engine, stop engine, fire separation rockets,

  • fire retro rockets, all this kinda stuff.

  • It does navigation and guidance.

  • You have stored in the memory a profile,

  • at this point in time I need to be here,

  • going this fast, going this direction.

  • Now realize that this is core memory,

  • so you have these magnetic cores,

  • you have the wires feeding through the cores,

  • you push a current down through a wire,

  • if you've got a wire, current's going in that direction,

  • the magnetic field is going to be in this direction.

  • If it's going this way, it'll be that way.

  • Make that a one, make that a zero.

  • There's 8192 of those on this plane, all right?

  • - [Linus] Yeah.

  • - Then there's 14 of those planes stack up

  • to make this module.

  • This module is what you're holding.

  • All this stuff now, the drivers to drive this thing.

  • - That's just to program it as a one or a zero.

  • - Because this is basically an analog process.

  • - Right.

  • - I'm not writing ones and zeros into a logic gate

  • and storing them that way.

  • - You're just sending a current --

  • - I'm actually having to make, magnetize a core

  • one way or the other.

  • And then I've gotta read it, and when I read it,

  • I destroy the magnetization, so I have to turn

  • right back around and --

  • - Write it again.

  • - Write it back in there, so that it's not missing.

  • - Oh, no!

  • - So there's one of these in this,

  • and then there's one of these now

  • in each one of these blocks on this wall over here.

  • - [Linus] Got it.

  • - So we have four, 8, 12, 16 thousand words of memory,

  • another four, 8, 12, 16 thousand words of memory.

  • Now when the Saturn's flying, both of these memories

  • are executing the same flight program.

  • - [Linus] Completely in parallel?

  • - That's right, and they're comparing the outputs

  • to make sure they're getting the same answer.

  • If they were to not get the same answer,

  • go into the sub-routine and say,

  • "I'm at this point in the flight,

  • I got these two numbers, what makes the most sense

  • to keep using," use that number and keep going.

  • So your critical parts are triple-redundant

  • in the logic, dual redundant in the memory.

  • As I recall, during all the Saturn flights,

  • we had like, less than 10 miscompares,

  • something like that.

  • It was a very small number.

  • - When you're building a rocket,

  • you have some important parameters

  • that you have to monitor.

  • Power, data bandwidth, mass, volume,

  • you have to manage these so they don't get out of control.

  • So you want a reliable system, but at some point,

  • you have to make a decision.

  • How redundant is redundant enough?

  • - Unreliability, that's the key,

  • because the more of these things,

  • the more core's you add, the more of this stuff you need,

  • the more unreliability you add to your system,

  • because sheer numbers of parts.

  • - Right.

  • - Luke is about to explain what it was like

  • to receive data from the Saturn V via telemetry

  • and then analyze it, and I'm gonna let this play out,

  • because I want you to understand how repetitive

  • and difficult this task was.

  • Today we could do this with just a few minutes

  • and some spreadsheet software, but back in the day,

  • they were the computers.

  • Like, the people were the computers.

  • So I want you to see it through his eyes,

  • through this historical lens so you understand

  • what it was like to analyze the Saturn V data.

  • - So did you pull the data down while it was flying?

  • - Things happen too quick in flight to.

  • - [Destin] How do you know you had --

  • - We get the data back and then we ana,

  • that was my job at IBM, was we were analyzing

  • the flight data to determine what worked,

  • what didn't work, if it didn't work on this flight,

  • how do we fix it on the next flight?

  • - Got it.

  • - And then when you get the NASA requirements

  • for the next flight, make sure we got everything

  • in place to do what we were supposed to do,

  • so the data tapes come from all around the world

  • through Goddard Space Flight Center's responsible

  • for that, so they get us the data and then we analyze it

  • and determine what happened.

  • Something would go wrong in the computer,

  • and it always goes wrong when something else

  • is messing up the telemetry system, so we would

  • actually get what they call an octal dump.

  • We have this 11 by 17 sheet of paper, 10-bit octal numbers,

  • so you'd have, there were four characters.

  • Zero to seven's as high as you go with octal arithmetic.

  • So you got all these things, I think it was like,

  • maybe 40 columns and 30 rows or something like that,

  • so we would get this thing printed out,

  • and all it's just numbers, well, the piece we're looking for

  • is in a particular place down here.

  • Well, the drop out is where we, you know,

  • telemetry dropout, we would actually get this printed out

  • 11 by 7 fanfold paper, spread it down this hallway,

  • get down on your hands and knees,

  • make a template, cut out the, you'll have a number

  • of measurements that'll always be the same, you know,

  • like a bolt, it never changes, so we know what

  • those number's oughta be.

  • So we cut the holes out and slide it down

  • page by page, "Oh, hey, these all look good!

  • "Okay, this frame's probably good."

  • So we go find so many columns, so many rows,

  • find the number we want, write it down.

  • - So you're looking for one -- - Go to the next one.

  • - If it bungs up something that you know is a fixed value

  • then it probably bunged up something else.

  • - That's right, and if the fixed value's okay,

  • then somewhere in there our number's probably okay.

  • - And then once you've got the problematic one,

  • I mean, is that just the world's nastiest sudoku puzzle?

  • How do you solve that?

  • - Well, no, you may have, you may have to do this

  • for many, many, many frames.

  • Then you take it to your desk and take those octal numbers,

  • convert 'em to decimal numbers,

  • go to a calibration chart and say,

  • "Okay, I got this number."

  • Go up my chart and say that means

  • it's five degrees Centigrade.

  • So you write down five degrees,

  • then you figure out what frame you are,

  • and that's about what time it is,

  • so you're, "At this time, I had five degrees."

  • Then you go to the next one.

  • Now you do this for about two weeks,

  • and finally you got enough to plot a graph by hand.

  • So you put all these numbers in

  • and you plot it by hand, and then you say,

  • "Hm, that wasn't the problem after all.

  • "Oh, well, here we go again."

  • (laughs)

  • - [Linus] Oh, boy.

  • - [Destin] This is Ed.

  • Ed is the head curator.

  • - Hi, Linus, how are you?

  • This is kind of an in-the-hand example of the memory cores

  • that you can see woven into the spread here

  • and then kinda under the magnification over here,

  • and there's about eight or nine of them in there.

  • So like Luke was saying, when you run the current

  • through there, it starts to spin that doughnut

  • in a particular direction, and that tells you

  • whether it's the one or the zero.

  • And you were saying they were woven on by hand,

  • and it was primarily women that did the work,

  • that had basically a bench top.

  • - So they would have like textile industry experience,

  • I guess.

  • - Um, I am actually not certain

  • what their qualifications were,

  • but they would sit with a bench top

  • with this thing mounted in a holder

  • with copper wire lengths and tweezers and their fingers

  • and a lot more patience than I have,

  • to weave these things through there,

  • to make sure they went through appropriately,

  • no kinks, no bends that were out of the spec,

  • and to actually make sure that the little doughnuts

  • go into across the way they should

  • and that it was all uniform

  • so everything would be predictable behavior.

  • - [Linus] Incredible.

  • - [Destin] I just wanted you to hold the physical bit,

  • now you know what that's like.

  • - I mean, this is, this is more than 8 bits,

  • so I'm holding at least a byte.

  • (laughs)

  • You can look at it that way.

  • - [Destin] So when you look at this,

  • what kind of emotion do you feel,

  • when you look at this, Luke?

  • Do you, do you, are you proud?

  • - Is it fondness, or is it more just,

  • "Thank goodness I don't have to work

  • on that bloody thing any more"?

  • - No, I'm gonna talk to one of my buddies

  • when you go out the building,

  • see if he'd hit you in the head.

  • (laughs)

  • - [Destin] To get this thing?

  • - Yeah.

  • No, that's a real piece of work,

  • and it looks, to people that come in here,

  • they say this just looks so much like an antique.

  • But again, we only had a few failures

  • during the whole flight that were intermittent.

  • We never had a catastrophic failure.

  • - People might say antique,

  • but I would say hand-crafted.

  • - Yes, it was a lot of hand work went into these.

  • - [Linus] Oh, you can tell, I mean, even just,

  • even these are clearly hand-baked.

  • - Well, they got the goop on 'em

  • because the big problem with this thing is vibration.

  • The memory that we were looking at over there --

  • - Yeah, you got physical rings on there.

  • - They test and test and test on that thing

  • to make sure that you hadn't got a kink in a wire

  • or a twist, 'cause if you do, the vibration's

  • gonna cause it to break.

  • Those things were made by hand.

  • The ladies actually wove these things

  • like you're weaving a piece of cloth.

  • Pretty amazing.

  • - [Linus] Oh, this is fascinating.

  • Thank you very much, by the way.

  • - I wanna say thanks to the sponsor today,

  • which is audible.

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  • Like everything from Natron in the Egyptian desert

  • to why Civil War battles were fought the way they were

  • because there were certain saltworks in certain locations

  • to why Gandhi walked to the ocean.

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  • which is a Roman sauce, like a Roman ketchup,

  • that we don't even know how to make any more.

  • This audiobook is amazing, and you should listen to it.

  • You can get is by going to audible.com/smarter,

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  • I know it would make more sense

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  • but this is what I'm actually listening to

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  • So audible.com/smarter, or text the word

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  • You will love this book, please do that.

  • That supports "Smarter Every Day."

  • When you support "Smarter Every Day,"

  • it lets me do more videos about the stuff I love.

  • If you want to see more of this interaction

  • between Linus and Luke, it's incredible.

  • Like on the second channel, there's a 30 minute video

  • of Luke going all the way down the rabbit hole.

  • This guy knows his stuff.

  • Like, I feel like I know rockets pretty well,

  • Linus certainly knows computers,

  • but when we're sitting there, it's almost like

  • Luke could just run around both of us.

  • Go check that out on the second channel.

  • Also go check out Linus's channel.

  • Actually, I'll just let Linus do an outro himself.

  • Go check out Linus's channel, Linus Tech Tips.

  • He's talking about, what's it called again?

  • - The instrument unit, basically we talk a little bit

  • about the computer but Destin's got a little more

  • information on that, but I really love

  • the cooling system on this thing,

  • it's gonna blow your guys's mind.

  • Unreal.

  • - It's awesome, it's at the top of the rocket

  • because as you got all three stages of the Saturn V,

  • you need your instrument unit way up here

  • so you can guide the Saturn V

  • before the Apollo computer takes over,

  • but Linus talks about details

  • of power and how that stuff works.

  • It's pretty cool.

  • - Yeah.

  • - [Destin] Thanks, dude, appreciate it.

  • - See you guys.

  • Thank you.

  • - [Kids] You're welcome!

  • - Thanks, guys!

  • - [Destin] It's called space camp.

  • - Space camp.

  • - [Destin] Yeah, so all those kids are here to learn

  • how to be astronauts and fighter pilots.

  • That's Luke.

  • - [Linus] No!

  • - [Destin] That's Luke.

  • - No way!

  • On the left there, apparently.

  • - [Destin] That's pretty cool, huh?

  • - [Linus] Luke Talley, there it is, far left.

  • That's nice.

  • - [Destin] That's pretty neat, isn't it?

- The Saturn V rocket took humans to the moon

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美國宇航局如何駕馭土星五號--每天更聰明 223 (How did NASA Steer the Saturn V?- Smarter Every Day 223)

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    林宜悉 發佈於 2021 年 01 月 14 日
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