At 26:14 I should have said 'dodecagon' not 'dodecahedron'. My script even said the correct term, I just read it wrong! Thanks @__a_4444 I recommend Usagi Electric's video on the Bendix G15 drum memory for anyone wanting to know more about exactly how the magnetic disc storage worked. The drum memory he describes is almost identical, just in a different form factor. He is able to communicate it far better than me and answers questions a few viewers here have asked in the comments. 1:01:19 should be the Gemini computer, I have absolutely no idea why I said ‘Mercury’ (which didnt have a computer). Thanks @AMcAFaves ruclips.net/video/ijRV_7sr4_k/видео.html
After seeing this I hope someone like Usagi or Curious Marc will get their hands on one of these and get it working. If there was enough hardware documentation you could probably build one except as you said the storage which would have to be emulated. Would still be fun to 3d print a small model of it with a microcontroller running the simulator. Appreciate the knowledge. I didn't know this existed until now much less the public got their hands on it.
Hey, great video! A university in my town is on the list 36:52 and we still have it! It serves a little bit of a different purpose though, as it has a glass top and serves as a coffee table in the library of the science department. It has a description etched on the glass top explaining it's the computer of a Minuteman but didn't know the background of it until this video. Thanks!
21:28 The reason why thrust termination ports work is due to the St. Roberts Burn Rate Law. It states that the regression rate, or how fast the propellant is burning back, is equal to a constant a times chamber pressure raised to the constant n power: rb = a*Pc^n. The a and n coefficients are based on the propellant mixture and are determined through strand burner analysis. When the thrust termination ports open, the chamber pressure drops rapidly, and thus the regression rate goes down. This is known as 'quenching'. The ports are angled forwards because the regression rate will not reach zero immediately, and will instead taper off as gas exits both the nozzle and the open ports. The angle of these ports results in zero net thrust. Some ICBMs actually angle the ports further forwards and use them to 'back off' the spent stage from the warheads and guidance bus. If you'd like to learn more there are a few good NASA papers online on solid motor quenching.
I also recall that one of the other stalwarts of space comms (Scott Manley, I think…) showed how another ICBM used bypass channels to steer the missile, by porting some of the chamber pressure sideways?
So technically the missile knew where it was because it knew where it was, and by subtracting where it was from where it ought to have been it can derive a difference, or delta velocity…
@@AHHHHHHHH21 because the person in the video speaks in a very contrived fashion and spends a full minute on a concept that can be explained in two sentences
Also, International Business Machines, producing hollerith machines that gave us widespread punchcards. (electromechanical computers are half a century older than I believed for a long time)
Spinny magnetic things were apparently a pretty established memory technology back then. A fella on Usagi Electric youtube channel is restoring a 1956 vacuum tube computer that uses a large magnetic drum at its core. The drum that came in his machine was shot but he managed to find another one in better condition in a museum machine and swap it.
by the sounds of it they are quite reliable as long as you dont run it too cold, would be even more reliable if any of the maintenance tools still existed to deal with stuff like bearings and blitzed time tracks like it could originally do
@@nickolaswilcox425yeah Usagi Electric is actually putting this machine project on hold due to cold weather out of concern he'll just trigger another drum crash if he fires it up when it's too cold
The desk computer shown reminded me of a model of the Centurion mini computer, also being worked on at Usagi Electric. For anyone wondering, the machine in question is the Bendix G-15. Not sure if it was this channel but there's a video about the guidance computer in a fighter jet that shows an earlier model sporting a Bendix computer at its heart, which given the size of those things when used as mainframes is mind boggling.
I need to catch up on Usagi Electronics - I love that channel. The way in which magnetic memory started off as drum format and moved to disc is weirdly identical to how vinyl records went from cylinders to discs.
I think passive devices were tracked by procurement lots. And if samples from a lot failed its functional or environmental tests, the entire lot was tossed. And later if a Failure Analysis Report on a failed module pointed to a flaw on say a resistor, the entire usage of that resistor lot could be traced and replaced if necessary. And these parts were fabricated to Mil-Specs and not commercial specs. Thus the high prices for components, but the mean time between failure (MTBF) of modules in these strategic weapons were incredibly good.
Real talk, "can it doom," is actually one of the best definitions of a computer I've ever heard. It's simultaneously very easy to understand and very accurate
The only issue with that definition is you have to give a big preamble about ‘how its only hypothetical as youd need to address a relatively huge amount of memory…..and figure out a way to hook up the IO….and it’d probably run at like 1 frame per hour’.
i feel like 'can it doom' has an entirely different meaning when the computer in question is hooked up to a multiple-megaton thermonuclear warhead. and the answer is 'yeah dude, it sure can!'
Back in the mid 70s we had one of the University donation units in our EE department. One of the advanced students built a seven segment numitron display (incandescent filaments) and switch setup that could be used to enter short programs. The S/N on each component was no joke. For their time the components were top notch. Our unit consisted of the processor half of the round split apart and mounted on a rack. I was very impressed by the reverse voltage protection. There was a huge stud mounted rectifier across the power input ready to short out the supply if it was connected up backwards. Sadly no exciting projects were ever built around it.
Thanks for sharing your experience- it’s so interesting to hear from people that actually used these, even if they were just largely used as ‘nerd toys’. Funnily enough, I made a video about numitrons before my channel took off. I have 6 of them on my desk displaying my channel subscriber count.
44:02 APL(A Programming Language) is an Array oriented programming language meaning that it's main datatype is a multidimwnsional array, it uses special charracters to represent certain functions it is a combinatorics base language. So the code is structered as a chain of Monadic(operation with only one operand) and Dyadic(Operation with multiple operands) functions as well as other operators. Ps: If anything here is wrong feel free to correct me
Yup it is really difficult to machine it. It is usually beryllium with a few percent of oxide as it is excessively brittle as pure metal. It machines similar to cast iron making crumbly dust rather than chips. Most of the structural bits of the MIRV platform are actually made of aluminum hardened with a few percent of beryllium and scandium. Super lightweight but a bit stronger than most common grades of steel.
…and I bet no one told the workers to not breathe it in to keep it a secret (like the poor folks in enrichment facilities who were told not to keep too many buckets of liquid close together…. but not why…)
@@Alexander-the-okExtremely toxic. As in "you were around someone who machined some without protections, your house needs decontaminating, your car will be taken away by authorities and disposed on, the workshop will be closed down, and you may never work again due to lung damage" toxic. Not a hypothetical
@mumblbeebee6546 oh we were warned it was beryllium or an alloy thereof, the prints just had cryptic part numbers that gave no indication of what they were for but the general shape pretty much told the tale for the sa parts. The mirrors and stuff for satellites and such were far more interesting though. Yup the stuff is truly awful from a machining standpoint, got to get the speeds and feeds just right, too fast and it cracks, too slow and it takes chunks out feed too light and it eats the edge right off the insert, too heavy and it breaks the insert the part or both. Combine the work hardening of titanium with the brittleness of cast iron and you got beryllium. 💀💀💀
JWST primary mirrors are made from beryllium with a thin gold coating. Very minimal expansion coefficient , so the mirror alignment won't need massive corrections
Soviet R7 used measurement and correction ground stations. But the first generation of R7 was more of a technology demonstrator or stop-gap solution than weapon system Later rockets used vacuum tube computers on board, with miniaturized vacuum tubes which had a size like a small part of the pencil and a lifetime from several minutes to several hours.
I need to try and find some good source material about the soviet rockets. I certainly am not surprised later models used miniature vacuum tubes - a lot of soviet hardware did from the mid 1960s onwards.
@@Feldmarshall12 There is 4 volumes of memoirs of Chertok, one of Korolev's «leutenants» with a lot of high-level information, but I'm not sure it was translated from Russian («Rockets and people»). Also, some sites in Russian were online ten years ago and I'm not sure they are still here, as links rot at an unbelievable pace :-( But mostly paper books of memoirs not pre-printed after 80s of previous century.
@@blacklion79 I did come across "Rockets and People". Actually English translation is freely available from nasa web page (just google the title). Do you have any idea on accuracy of those memoirs? Published in the 90's, around 30 years after, I imagine they could not be 100% accurate. As far as I understand he didn't have access to government run archives when writing, did he? And anything published before 90's would be run through machines of propaganda and censorship, again impacting accuracy. This is stark contrast to NASA history series, where authors were supported by access to many documents still held in archives and could arrange for meetings with people that were still in NASA at the time of writing. But maybe I worry too much ;)
I commanded a Missile Combat Crew in the early 80s. My system was Minuteman III. One morning when I was sitting in the Squadron waiting to go on alert, I happened to stumble upon an old Dash 1 Tech Order for the original Minuteman I system and started to read. I was shocked to learn that the first Launch Control system had no computer at all. The entire thing was based on mechanical relays. The Enable commands were simply electrical continuity circuits. Interrupt the circuit and the sortie enabled. If power at the capsule dropped, all the sorties in the flight would enable. Daily SCN tests dropped connected sorties into Standby mode so the crew could verify communication. The whole design was surreal to me given all the nuclear surety that was deliberately built into the software that I used. I couldn't conceive of that kind of system without a computer. But I guess it makes sense given the level of technology in the early 60s. The computer in my capsule was a Rolm 1666B, especially built for the mission. Not much by today's standard but it did the job.
Sorry if this is a stupid question, but what was it like doing your job? I can't imagine the feeling of working next to such awesome (in the old sense of the word) machines.
@@GulmoharBloom Missile crew duty was a 24 hour alert consisting of alot of tedium interspersed with intense activity. It was cold in the capsule so I generally wore a sweatshirt. (The first thing you did on alert was take off your uniform - one of the many, Many, MANY things the movie "Wargames" gets wrong.) Taking off the sweatshirt was a good indication of how busy I was. We had daily tasks - making sure the capsule was OK, verifying the targeting info in our sorties, calibrating the missiles every now and then. Mostly we watched. "Status monitoring" was the parlance. Security, faults, maintenance, and comm. Did I think about the possibility of war? No, not really. PBS did a documentary in 1983 called "Nuclear Outpost" at my base. One of the reporters asked me if I had nightmares about nuclear war. I said "No, I have nightmares about Two Officer Policy violations" (Being alone in the capsule was a serious offense.) I still had those nightmares 10 or 20 years after I got off crew. That said. Just before I got on Crew, "something happened" (we will leave it at that) and the readiness of the missile crews went up to the point that they inserted launch keys. (That's a long way from actually launching missiles btw but it is still what you call a significant event.) That's only happened a handful of times in history. The command post on the base had a direct line to all the crews in the field, and the first direction was "Do not call home. Keep the outside lines clear." Everything was restored to normal in a few minutes as the "something" was resolved. Since the launch switches are sealed to prevent tampering, a lot of people were immediately dispatched to the field to replace the seals. They said the crews on alert were just white and still shaking. So, yes. We knew it was real. But it was mostly remote from consciousness. Would I have turned that key if so directed? Yes. No doubt in my mind.
@@carljacobs1260 It just boggles my mind to meet (?) someone who would be/was involved in nuclear warfare. I'm not sure if I could have turned the key if it came down to it, but then I won't ever be in a position to do so. Thank you for responding, it's given me a new perspective to consider as I read more about nuclear war. Have a nice day!
@@GulmoharBloomWhen the time you fictionally turned the key you would be very very willing and wont hesitate since the fcker that lauched first certainly didnt
@@carljacobs1260 Oh come on, WarGames was - technically at least - fantasty, albeit terrific movie. Was documentary you mentioned used in Gwyne Dyer's "On War" or "First Strike" or was it other?
The core rope modules were wild. When they reprogrammed the AGC to use as a fly by wire computer, they had to race to write the code before the core rope manufacturing facility was closed forever.
As a very young child I got to see a core memory computer being used in production. I found it really neat that one could see where every physical bit was stored. (I've tried to determine what precisely machine it was but to no avail.)
That magnet hard drive sounds more like a parallel-track magnetic tape loop made out of rigid bodies instead of bands of elastic or celluloid. Wait. It's planar drum memory.
Yea, the one used for the D-17 is a drum memory. The models produced for less-extreme environments (including the Hound Dog missile) were more like a single platter hard disks. See Appendix A of _MEM-BRAIN FILE, Four versions for DCA_ for details.
I love this series on early computing history! The intersection with the more advanced weapons of war is fascinating (although very much expected); I may abhor war but its still a very interesting topic (probably because of them having to solve novel, and difficult problems), which further complements my interest in learning about early computers and the like. I appreciate you way of relaying information in videos quite a bit too!
Studying CS, i do get a more general, and vague ish, information on early computing history, but seeing those actual examples makes it truly impressive what they had to do in those early days.
@@alexhajnal107 War can be more productive WW2 had a lot of technological advances although this happens more for total wars and cold wars,the modern insurgent style wars or small scale state wars dont produce much new technology.
26:13 That's not a dodecahedron. It's a hollowed out dodecagon prism. A dodecahedron is a polyhedron with 12 faces. The prism has 14 flat faces, not counting the extra ones from hollowing it out.
‘Extruded dodecahedron’ is what i called it because there's no way i was going to try and say ‘dodecagonal prism’. ...on further reflection, I'm still wrong. It should be 'extruded dodecagon'. The one chance I got to say that and I still got it wrong!
I was looking for this comment. Shout out to Mr Steeves my grade 9 math teacher for very effectively teaching us shapes. I think I made an icosahedron for that class.
Actually saw one when I was studying in St. John Fisher College in upstate NY. The construction and support structure on the PCBs was impressive, support for every single component: transistors, capacitors, resistors... very meticulous engineering.
The fact that you don’t have 10x the subscribers you currently have is as shocking as it is tragic. Consistently high quality uploads spanning an hour or so in length about extremely complex topics with in-depth explanations and analyses. Unreal
It simply amazes me that my SSD that takes up about the same space as about 5 BIC pens, can store 136,500 times the information as a drive that took up 3 refrigerators worth of space in 1956. There have been humans alive (and in fact my grandparents are examples) that have seen this evolution in real time.
Assuming decent gyros and accelerometers, you can significantly minimise compounding error by using low-pass filters at your ADC inputs. This can drastically reduce the sampling frequency required to maintain a reasonably accurate positional and velocity vector. If implemented correctly, there is no quantisation error other than the bit depth of the ADCs, and you don't lose the contribution of any high frequency components, those get averaged into the signal by the filter.
@@mrsquidly6395 So before we had things like high speed magnetic storage medium for computers we needed some way for computers to retain a lot of bits of memory punch cards weren't fast enough and couldn't be written and rewritten easily. Although memory cells could be made of tubes they were very energy and space inefficient for this purpose. So the idea of delay line memory was made. Commonly filled with mercury for its density it was a long tube with a transducer at both ends. Bits were fed in as an audio waveform at one end travels through the mercury and is read out the other end. If the bits aren't read out and fed back in to the start they are lost.
@@Jackpkmn I'm gonna have to search this up because I'm still not getting the full picture even with how well you've articulated the concept to me. I can't quite tell if I'm dumb or if you're on a level I've yet to even begin grasping. I saw mercury and all of a sudden everytime I try to comprehend it I just keep visualising one of those old lightbulbs and It keeps throwing me off. A.D.D brains there telling me "ah, we know mercury and it's in a tube so lightbulb" I'm starting to lean towards the idea that I'm probably just dumb haha
@@Jackpkmn does the wave propagates through the mercury bounce back and forward storing the information in diminishing waves and as a result acts like a very short memory? Hmm, also if not, i thought sound propagates faster in denser mediums? What does the delay serve?
The Soviets used a ground-based guidance system in the R-7, the basis of which was copied from the Germans at the end of World War II. The R-7 ICBM was tested in the Northern Urals in 1959 and there were some casualties there during the testing phase, including the members of the Dyatlov group who were involved in the testing and evaluation process. They conducted these tests with active warheads set to a lower yield of 1.6 megatons (standard RDS-37 warhead). After completing the series of tests, the R-7 was officially handed over to the Soviet missile forces in 1960. For those interested in more details about the Dyatlov Pass Incident, I recommend watching my videos about the entire case and its complete solution.
I work with inert gas gloveboxes a lot. The embedded controller in most of them is just a glorified MS-DOS machine. So yes, I played Doom on one of them once. With the keyboard and mouse being in the glovebox. We have USB passthroughs at the back of the thing, so that we can run things like UV spectrometers under inert conditions.
I really appreciate the shoutout to Hal Laning. Besides doing the real-time OS for the Apollo Guidance Computer, he created the first compiler. People often credit Grace Hopper for that, but what she called a compiler was more like what we could call a linker today.
She did develop FLOW-MATIC which led directly to COBOL so she can be credited/blamed with creating the first high-level language for business applications, usable by people without any training in mathematics. (Guess whose work led to FORTRAN though.)
It's kind of annoying that Hopper is remembered in popular parlance for the compiler....and then everyone has to point out it's a semantic quirk and she didn't technically invent it. Because she did SO SO much more than just invent the linker. She was an excellent presenter/orator too....I imagine she'll appear in one of my videos in the future.
Giving Hal his due does not reduce Grace Hopper's legacy by any noticeable degree. She and Margaret Hamilton were and are (respectively) towering figures casting long shadows, ironically given both stood only a little over 5 feet.
When you pointed at the need for high precision of guidance and possibility of corrections (22:07), you mentioned missing St. Petersburg and hitting Helsinki. Well, at the time the minuteman were developed and were operational it was Leningrad they were aiming at, since the name St. Petersburg was reissued only after the collapse of Soviet Union I don’t think this correction is a must, but I figured it would be something to note
Thus Lt. Chekov in Star Trek had scotch "invented by a little old lady in Leningrad." How were the Star Trek writers to guess it would change back to Petrograd by then?
@@sciptick There are people born in towns which changed their name upon independence. But they speak of the place where they were born, not what some politician called it later. Sometimes an international airport changes its name but the codes for that location are still the same. There is one 50 miles from here but a Liberator pilot would use the same name. As would a local.
The D-17B used discrete DRL (Diode Resistor Logic) circuitry with DTL (Diode Transistor Logic) where needed, but the MMII used the D-37C which was one of the first guidance computers to use SSI integrated circuits (The other being the Apollo Guidance Computer).
IIRC beryllium is a very stiff metal for its weight. It's also used in the JWST mirror segments for the same reason. Probably also has a low coefficient of thermal expansion. Nice modern IMUs still output an integrated delta_v over their sampling interval as well.
You have no idea how much I enjoy this video. I have always been fascinated by early computers. Back when I was in school and briefly after, I only had time to read *a little bit* into these computers. Here, you've gone *all the way!!!*
I am looking forward to the episode about the Navy's fully-networked, transistorized refrigerator-sized missile fire control computers, put into operation in ~1964. It is one thing to equip a computer to work control surfaces and thrusters, another to have it swing a robot arm into position and launch missiles. Many ship captains got into hot water trying to keep the computers off their ships, but the need for fast response left no possibility of them staying in the loop. Where more capacity was needed, they added more of them, and all talked via radio link to their counterparts in nearby ships to coordinate their activity. So a missile battery on a destroyer could be used to protect a nearby aircraft carrier, without crew help. I gather those machines had a role in Apollo as part of the worldwide communication and tracking system, but the details escaped me.
Alexander, you consistently impress me with your focus, dedication and contextual research - and yet you are brilliant at presenting, storytelling and not to forget, visual humour where possible. I wish I’d had professors and lecturers like you! Thank you for sharing your work with us!
Dow Chemical developed a process control system in house called the Mod5. I don't know if it used a D17, but I do remember the processors were repurchased missile controllers. They were programmed with a Dow specific version of Fortran jokingly called Dowtran.
you and Artem Tatarchenko are a match made in heaven lmao. he is so talented and really adds a lot to your really well written and interesting essays :)
While the animation is quite good, a few details do distract me quite a bit as a big fan of the Minuteman system. The silo layout, in a forest and surrounded by buildings definitely seems more like a Soviet style missile silo installation. The US launch facilities are very spartan and remote, just a fence and dirt and gravel patch around the silo door, usually in the open plains of the upper Midwest. Also the silo door actuator is much more violent. While a lot of footage of launches comes from the Vandenberg silos, where they slide open smoothly on rails, those silos were designed for repeated use. The actual deployment silos have a much more simple system. Hydraulic rams push with great force the concrete door on smooth metal rails with enoug energy to make sure that even if the silo is covered by dirt due to a near by detonation that it can get out of the way. The only thing stopping it is how much friction it has once it comes off the rails (and in reality could easily breach the perimeter fence). Also the tail end renders show two exhaust nozzles. The Minuteman first stage had four nozzles fed by a single solid rocket engine. Anyway, nitpicking but small details noticed by a pedantic nerd.
Yeah, I saw a couple of of preeecessors, probably for the Titan II, of these being thrown out from the local University. They were supposed to go to hazardous waste disposal, as they used a cooling system using liquid mercury. Really sturdy devices with inch-thick aluminum cases. You couldn’t see much inside the case as it was filled with plastic foam. Wish I had kept them.
@@alexhajnal107 I had the opposite experience-- I bid on two PDP-11/44 systems, won them, then found out they were just the cases, someone had pulled out all the cards.
There is a VERY tiny subset of the human population who can appreciate the near-erotic beauty of those circuit boards, with their intricate runs & tightly-packed, imminently symmetrical & intimately considered component layouts. I belong to this group. Thank you for sharing those images. I want to get one of those boards under a microscope, but I know this is as close as I’ll ever be. It’ll have to be enough. Thank you.
jeezo, RUclips is hammering this with unskippable pairs of 20-second adverts every few minutes. I'm using a VPN so they're unintelligible ads for (I think) Danish supermarkets but I keep needing to mute
Alexander, this is a very interesting video. I used to work with a very early DCS, it was designed and built by the company that used it in its pharmaceutical manufacturing business as process control and batch reporting. I only had a bit of time to learn about it before we replaced it with a modern standard (S7-4xx). I specifically recall an analog input board with hard-codeable limits (DIP switches and jumpers, 8-bit, low and high warning and alarms, it triggered an interrupt on the central and fed it to a card managing all the interrupts and their privileges. It was a headache to implement the interrupts as the only documentation we had was a copied copy of someone’s handwritten notes that had been used during qualification and then copied again and put in a binder. It worked for decades but there was a fatal flaw in the design and it hadn’t been picked up. It was quite the hassle to get the HAZOP reviewed by the chemist who just muttered „boy, we were very lucky“ and then update the documentation to reflect the corrections we had to make. Fun. How far is your SDS and the SMDS for this project? 😏 Keep it coming, love it!
Beryllium is super lightweight, super strong, and has a very low thermal expansion coefficient, so parts made from beryllium alloys can be made with tighter tolerances than aluminum or titanium. There's also no risk of sparks or static buildup, which can reduce compounding errors in inertial guidance systems. But... beryllium poisoning is absolutely horrible, it makes asbestos seem like a mild nuisance in comparison
Oh never expected to see you using godot while I'm making hobby game with godot as I watch! And as a CS Student who had 'not so good time' with SPARC and MIPS, I was really surprised to see 48:20 Instruction bit mask and it's naming were basically same since that long ago. Truly we were just using an improved version of D-17b guidance computer! Amazing video, now this one's my favorite.
The tethered missile tests apparently were conducted with dummy second and third stages, and I believe the tether was to pull the missile away from the silo, avoiding damage. Cheaper than special hardware for one test.
Thank you for another awesome instalment to your growing long-form content library. I love the low level tech on here- please continue with the magic jazz :)
Coming from an audio guys perspective, I would guess beryllium was used for its unique combination of high stiffness and low mass, plus the fact that it’s really good at damping high frequency and thus would make the system less susceptible to feedback from vibration. Beryllium is used exactly for these reasons in über high end tweeter cones
The computer was under the platform that carried the RVs. It also had either an electrostatically levitated sphere gyroscope or a helium neon 6 axis ring laser gyro in the dead center. The main middle battery was a 28V NiCd battery but the ones in the actual nukes were magnesium based thermal batteries. What they got in the more modern ones is a lot smaller and more accurate.
on the very brief note towards the beginning about disconnecting the device from the purpose. that’s a big deal for me as someone who has plenty of ethical and philosophical things to say about war & politics (I mean who doesn’t, right) but also *loves* military technology, history, theory, etc. always been drawn to that stuff since I was very young, so taking the hate and tragedy from something’s existence and putting it to one side is a critical part of enjoying things I’m passionate about. and of course it makes videos like this possible. glad I found you this morning.
I love when people learn about the fundamentals of computing. It's so awesome that you can program anything with just the base building blocks of either NAND or NOR for logic constructions
This video has made me wanting a D17 replica!, (probably an arduino is overkill but it would be way cool having a 3d printed chasis, and wired ports to do electrically equivalent terminals), just to show off driving a 3d printer with an ICBM.
not a dodecahedron (which is the standard 20 sided die used in games) but a dodecagonal cylinder (12 sided polygonal cylinder)... great video, the names of some of the companies and projects brings back some early memories of my career... keep up the good work...
40:29 I'm an analytical chemist, so I can see the utility of using a computer to extract information from AutoAnalyzer data. I would guess it would boil down to solving systems of linear equations, something the D17B would excel at.
If not mistaken, the first computer on russian lauch rockets was the s-530 on the 4th and last N1. As far as ICBM, someone knows? Before that it was a program cam
5:22 The historic sequence of an operator at a console, I presume a first response operator simulating a launch initiation, is remarkably similar to the opening sequence of "Wargames". This is not surprising, as that was set in a first response bunker. But usually Hollywood gets a lot very wrong, in that case the actions shown in the historic video are almost point for point the same as the movie.
21:30 That is trivial. The explosien caused a massive leak that bypassed the thrust nozzles completely. Thereby reducing the thrust not to nul but to a fraction. That influence sufficed to control the terminal velocity.
That’s what I initially thought but all the sources on this state it wasnt a thrust bypass but a near instantaneous termination as the reaction abruptly stopped. A few other viewers have clarified its because the rapid drop in pressure blows off the top layer of fuel and stops the reaction.
Thanks for this interesting bit of history. I studied electrical engineering at Auburn University from 1966 on and those studying aerospace engineering had an advantage over us. At least one of those free computers from the USAF were passed along to them.
When I first realized, that I needed a computer, it was a Commodore +4 on display in a highstreet bookshop window, in 1984. -Now, if you know about the Commodore line of computer models, you might be going "Oh, no poor Jim. Not the Plus/4!", know it then, that at that time I was thirteen years old, and anything like a great looking computer would have to get funding, and to get funding the project would have to get approved by my father. I did not get a computer before three years later, as my father; a geologist believed in "the human faculty for calculation far exceed that of such a toy". When my father saw what I could do with my first computer he was not impressed, but when I upgraded to an Commodore Amiga 500 and showed him what I could paint in DeLuxe Paint 3, he bloody well went and bought me a RAM expansion, that cost the same as the computer. I have told him, time and time again: You should have funded me, in 1984, and he figured so himself. The US Department of Defense must be the cool dad; "I hear that you lads would really like to get to grips with programming? Here's a pick from the bargain bin" Any computer is leagues ahead of calculating with pencil and paper. Thanks for posting about that ground breaking machine :3
@Alexander-the-ok I would love to see a video on SM-3 and especially all the different (or one of the) kinetic kill vehicle programs. Not sure if that is a realistic video idea since SM-3 and the EKV-derivative warheads are still in service, so I imagine details on the design of any of the EKVs are difficult to come by.
Absolutely unconfirmed at this stage, but an EKV may make a cameo in the next video. I may well do a segment on EKVs in a future video, but there isn't really enough info out there for me to do a full video (I looked into the idea a while back).
You say there is one in the Computer History Museum? A “nightmarishly difficult restoration project”? I have a funny feeling that it sounds like an open challenge for certain electric bunny themed channel or maybe a space hardware obsessed Marc’s channel in the future. Great to know that there are still some extremely obscure, but historically significant computer artefacts left to dig into over the following years. Cheers!
47:29 Ehh, a dedicated accumulator register is afaik really only a feature of ancient CPUs and their direct descendents (e.g. x86). More modern CPU architectures pretty much always just have a bunch of general-purpose registers that can be freely used as source/destination register operands for arithmetic instructions. The only recent architecture I'm familiar with that uses separate registers for various roles is a DSP, but it has not one but 16 accumulator registers.
Just like the real minuteman(men with muskets), it was never intended to be used, but only at the direst of times. The minuteman have made sure, we dont have to use them. That is a victory by itself.
27:36 the first integrated circuit was created in 1958 by an engineer at Texas Instruments who created the first ic based computer in 1961. “ 1961 Jack Kilby's colleague Harvey Cragon built a demonstration "Molecular Electronic Computer" for the US Air Force to show that 587 TI ICs could replace 8,500 transistors and other components that performed the same function in a conventional design.”
I knew that, at that time, inertial navigation systems did work fairly well on aircraft, at least at relatively short distances. Using it on an ICMB (a solid fuelled one, no less) was a completely different ball game, as beautifully explained by this video. One could be forgiven for assuming that, because it dealt with a much less dense atmosphere for most of its flight, aerodynamic deviations would be lessen. But it isn't necessarily so. Flying at low altitudes, at a more or else constant density, even while prey of wind vectors, should likely be an easier problem to tackle with late 50's and early 60's systems.
I think you are right about one person getting credit. You would think from some documentarys that Kelly Johnson for instance designed and built the SR-71 all by himself. Plus many other planes.
Amazing content, so many engineering channel videos just sound like Wikipedia article reads, but you go far more in depth and hold my attention the entire time!
Just for fun, I wanted to know how fast Doom would actually run on a D-17B as the CPU. There's no way it could store Doom on it's HDD. It probably can't drive a raster display either, so let's assume some IO upgrades to handle those parts. So here's my SWAG: According to a post on the Doomworld forums, a user estimated that Doom needs 32 instructions per pixel, so we'll use that. He mentions that the 32 instructions are on a 486, so it's likely not the simple instructions the D-17B has, but I'm not going to dive into the Doom code to find out exactly what was used. Wikipedia lists the timing for the add, multiply and load instructions, so I'll arbitrarily use those. I picked an arbitrary mix of 10 adds, 12 multiplies and 10 loads. The wikipedia page says we can do two multiplies as the same time, so we'll do the timings that way. All told, we end up with a single pixel taking 4.8 milliseconds.. Assuming my guess about 4.8 milliseconds is right (which is probably wrong), we get the following: Doom runs at 320x200, so rendering a single frame takes 310 seconds or just over 5 minutes. Doom runs as 35 fps (ideally) so 1 second of Doom takes about 3 hours to render.. The fastest listed speedrun of Doom is 4 minutes and 39 seconds. That speedrun would take 35 days on a D-17B.
Love it thanks for this! There is one thing missing, and its the main reason i never coded the timings into my sim: read write to the disc. Much consideration is given to this in the original programming guide as reading from a ‘sub optimal’ sector would need us to wait up to 10ms just for the drive to rotate to that sector. I have no idea how much more time we’d need to add in for read/write. But every time a variable is read in incurs a minimum of about 80 microseconds.
My favorite word for this kind of rough approximation is 'guestimate' (noun to that would be a guestimation). It isn't my creation, but I can't remember where I first came across this.
Thank you for another extremely professional, extremely interesting video. Your nickname (while very funny) doesn't do your content justice. Do you also publish on something like Nebula or similar? Your content is definitely good enough for that, and the amount of ads RUclips is showing right now on everything makes me want to quit youtube forever (it is literally just your channel and *very* few others that keep me here.)
Thanks. You've just reminded me - I've just gone and deleted a bunch of ad breaks from the video. RUclips's automatic placement is very....liberal. I do publish ad-free videos on Patreon, but it wouldn't be good value for money compared to something like Nebula where you'd get way more channels. I've not even thought about Nebula - if the opportunity presents itself I'd consider it (I just do this as a hobby alongside a full time job so I don't really think very hard about monetisation etc). Btw, when I want to watch long videos ad free, I just download them using a third party service.
@@Alexander-the-ok For a pure hobby project the quality of your research and production is quite amazing. I have long been thinking about Patreon for a few channels, maybe I should finally just do that. (That'll have to wait a few months though.)
The fact that the missile could compute its location in 3d space on a globe with just gyros.. I mean it sounds right algebraically, but how tf did they manage to do it so accurately while strapped to a fucking rocket? All that rattling around.. We take GPS for granted now and I can see why the military was so interested in restricting civilian use of it in the early days. No one, short of a superpower, was going to be able to machine a guidance system so precisely. Without that hurdle though, it’s probably magnitude easier to make a functional icbm
The 3rd stage termination shapes charges "switched off" the propulsion, by allowing the motor expansion gas to go everywhere following the path of minimum resistance, but not through the narrow, high resistance, rocket muzzles. Resulting in a lost thrust for the whole rocket equal to an engine shutdown in a liquid propellant rocket. The solid propellant was designed to be sufficient for max possible distance, any release of pressure, due to detonation, shortened the ballistic curve
51:06 Actually, if we're allowed to clobber those two unused middle bits then split add/subtract is particularly simple: split add: accumulator = (accumulator & ~0x1800) + (operand & ~0x1800) split subtract: accumulator = (accumulator | 0x1800) - (operand & ~0x1800) This is assuming 2's complement representation is used... I'm really not sure why you went with sign-magnitude considering 2's complement is the native format of both the D-17b and modern computers (for signed integer/fixed-point arithmetic), using sign-magnitude seems like it would just make arithmetic way more complicated to implement than it needs to be.
17:30 - Only the Atlas D used this particular type of guidance system, the Atlas E and Atlas F used a fully internal inertial guidance system just like the Polaris, Titan II and Minuteman (Although its' guidance and control circuitry was all analogue).
A very fine history of the whole topic of guidance is Donald MacKenzie's Inventing Accuracy: A Historical Sociology of Nuclear Missile Guidance (MIT Press, 1993), a bit pricey in print these days but available on the Internet Archive
@@Alexander-the-ok I'm going to second the comment above. I actually came to post about inventing accuracy, really fine book that i assign in an engineering course that I teach.
At 26:14 I should have said 'dodecagon' not 'dodecahedron'. My script even said the correct term, I just read it wrong! Thanks @__a_4444
I recommend Usagi Electric's video on the Bendix G15 drum memory for anyone wanting to know more about exactly how the magnetic disc storage worked. The drum memory he describes is almost identical, just in a different form factor. He is able to communicate it far better than me and answers questions a few viewers here have asked in the comments.
1:01:19 should be the Gemini computer, I have absolutely no idea why I said ‘Mercury’ (which didnt have a computer). Thanks @AMcAFaves
ruclips.net/video/ijRV_7sr4_k/видео.html
Thanks for the awesome video btw.
Are you British Perun? Your presentation reminds me of that
After seeing this I hope someone like Usagi or Curious Marc will get their hands on one of these and get it working. If there was enough hardware documentation you could probably build one except as you said the storage which would have to be emulated. Would still be fun to 3d print a small model of it with a microcontroller running the simulator. Appreciate the knowledge. I didn't know this existed until now much less the public got their hands on it.
So the D17 is what they used FORTRAN and COBOL for?
Or was that Pure Machine Language?
Hey, great video! A university in my town is on the list 36:52 and we still have it! It serves a little bit of a different purpose though, as it has a glass top and serves as a coffee table in the library of the science department. It has a description etched on the glass top explaining it's the computer of a Minuteman but didn't know the background of it until this video. Thanks!
"Your first desktop will blow you away". (I'll show myself out).
That jokes pretty rad!
These are going ballistic
@@iitzfizz ICBM what you did there.
Cringe....
Dude! You’re not getting a Dell!
21:28 The reason why thrust termination ports work is due to the St. Roberts Burn Rate Law. It states that the regression rate, or how fast the propellant is burning back, is equal to a constant a times chamber pressure raised to the constant n power: rb = a*Pc^n. The a and n coefficients are based on the propellant mixture and are determined through strand burner analysis. When the thrust termination ports open, the chamber pressure drops rapidly, and thus the regression rate goes down. This is known as 'quenching'. The ports are angled forwards because the regression rate will not reach zero immediately, and will instead taper off as gas exits both the nozzle and the open ports. The angle of these ports results in zero net thrust. Some ICBMs actually angle the ports further forwards and use them to 'back off' the spent stage from the warheads and guidance bus. If you'd like to learn more there are a few good NASA papers online on solid motor quenching.
That’s really interesting, thanks.
I also recall that one of the other stalwarts of space comms (Scott Manley, I think…) showed how another ICBM used bypass channels to steer the missile, by porting some of the chamber pressure sideways?
So technically the missile knew where it was because it knew where it was, and by subtracting where it was from where it ought to have been it can derive a difference, or delta velocity…
That is actually 100% correct
I don't get why people found that thing confusing. Its pretty straightforward.
@@AHHHHHHHH21 because the person in the video speaks in a very contrived fashion and spends a full minute on a concept that can be explained in two sentences
@@cockatoofan yeah fair
@@AHHHHHHHH21 The average person can barely use a smart phone.
apparently, IBM was the abbreviation for intercontinental ballistic missile, its all coming together
Also, International Business Machines, producing hollerith machines that gave us widespread punchcards.
(electromechanical computers are half a century older than I believed for a long time)
How did they know before WWII that they’d be making ICBM’s
It’s crazy how forward thinking Big Blue is
Also, coincidentally, IBM is HAL shifted by one character place. Spooky, woo!
Imagine there was an imcoming ICBM but inside the re-entry vehicle it was just a computer.
An Inter-Continental Business Machine, if you will
@@scunnerdarkly4929that is a magnificent observation! 🙌🏼
Spinny magnetic things were apparently a pretty established memory technology back then. A fella on Usagi Electric youtube channel is restoring a 1956 vacuum tube computer that uses a large magnetic drum at its core. The drum that came in his machine was shot but he managed to find another one in better condition in a museum machine and swap it.
by the sounds of it they are quite reliable as long as you dont run it too cold, would be even more reliable if any of the maintenance tools still existed to deal with stuff like bearings and blitzed time tracks like it could originally do
@@nickolaswilcox425yeah Usagi Electric is actually putting this machine project on hold due to cold weather out of concern he'll just trigger another drum crash if he fires it up when it's too cold
The desk computer shown reminded me of a model of the Centurion mini computer, also being worked on at Usagi Electric.
For anyone wondering, the machine in question is the Bendix G-15. Not sure if it was this channel but there's a video about the guidance computer in a fighter jet that shows an earlier model sporting a Bendix computer at its heart, which given the size of those things when used as mainframes is mind boggling.
I need to catch up on Usagi Electronics - I love that channel. The way in which magnetic memory started off as drum format and moved to disc is weirdly identical to how vinyl records went from cylinders to discs.
Yup, core memory, used ferromagnetic toruses to capture state. This is where we get the phrases "core dump" and "... Dumped core..." Today.
So they gave a serial number to every resistor in a computer and tracked it all using paper.
A logistical nightmare is an understatement.
Especially considering this, if I uderstood this correctly, for all of the Minuteman I missiles, spread across various bases and units ...
@@HerrmannStahl I guess for a nuclear ICBM you probably want a lot of tracking of where the pieces might end up somehow
I think passive devices were tracked by procurement lots. And if samples from a lot failed its functional or environmental tests, the entire lot was tossed. And later if a Failure Analysis Report on a failed module pointed to a flaw on say a resistor, the entire usage of that resistor lot could be traced and replaced if necessary. And these parts were fabricated to Mil-Specs and not commercial specs. Thus the high prices for components, but the mean time between failure (MTBF) of modules in these strategic weapons were incredibly good.
@@davidmercado9293 yeah ok but where did this resistor come from or wait we lost it.... then found again. what number was it?
Serialised components would be tracked using punched card systems: either electromechanical tabulators etc. or room-sized mainframes.
Real talk, "can it doom," is actually one of the best definitions of a computer I've ever heard. It's simultaneously very easy to understand and very accurate
In the late 90s that was one of the requirements we had to keep a system.. DX processor and Doom.
The only issue with that definition is you have to give a big preamble about ‘how its only hypothetical as youd need to address a relatively huge amount of memory…..and figure out a way to hook up the IO….and it’d probably run at like 1 frame per hour’.
i feel like 'can it doom' has an entirely different meaning when the computer in question is hooked up to a multiple-megaton thermonuclear warhead. and the answer is 'yeah dude, it sure can!'
"can it doom," (☞ﾟヮﾟ)☞ made my day XD
everything, quake, doom, fallout... even do light scribe (if you find a bunch of ruskys dancing YMCA close to a wall)
"Jesus, your computer is slow. What are your specs?"
"One 800 kilotonne thermonuclear warhead."
"What?"
Some kids have RGB in their computer cases, this one had alpha, beta, gamma, x-ray, UV... whole spectrum, in lethal doses up to 20 miles.
I wouldn't exactly call a Mach 23 computer, slow.
@@totojejedinecnynick great to play Fallout! graphics on 50000ºk colors, and 800 kilotonne bass...
and a speed of 40000km/h
Now we just need someone to beat Ocarina of Time on it before the rest of the, uh, hardware vaporizes Moscow
Back in the mid 70s we had one of the University donation units in our EE department. One of the advanced students built a seven segment numitron display (incandescent filaments) and switch setup that could be used to enter short programs.
The S/N on each component was no joke. For their time the components were top notch. Our unit consisted of the processor half of the round split apart and mounted on a rack.
I was very impressed by the reverse voltage protection. There was a huge stud mounted rectifier across the power input ready to short out the supply if it was connected up backwards.
Sadly no exciting projects were ever built around it.
Thanks for sharing your experience- it’s so interesting to hear from people that actually used these, even if they were just largely used as ‘nerd toys’.
Funnily enough, I made a video about numitrons before my channel took off. I have 6 of them on my desk displaying my channel subscriber count.
44:02 APL(A Programming Language) is an Array oriented programming language meaning that it's main datatype is a multidimwnsional array, it uses special charracters to represent certain functions it is a combinatorics base language. So the code is structered as a chain of Monadic(operation with only one operand) and Dyadic(Operation with multiple operands) functions as well as other operators.
Ps:
If anything here is wrong feel free to correct me
Maybe Alexander only the ok, but man, that film was great
No, it wasn't. It was made with the solely purpose of collecting likes and views. There's no honor or glory in it's intended purpose.
@@barmalinithe guy built a working D-17 sim. Give him some credit
@@Jujukungfu I once built a working Sincler ZX Spectrum on pure logic gates, so from me certainly a pat on the back
Oh lol now I get that username. That's clever 😂
A CNC controlled by a Minuteman guidance computer is the most awesome thing I've heard in a while!
Amazing video as always
I wonder if the end command was the traditional G00 or "Moscow"...
I have a feeling it would be compelled to crash the head 😂
Beryllium is exceptionally stiff. It is terrible to work with, the dust in particular though. Great video, thank very much for the time these take.
Yup it is really difficult to machine it. It is usually beryllium with a few percent of oxide as it is excessively brittle as pure metal. It machines similar to cast iron making crumbly dust rather than chips. Most of the structural bits of the MIRV platform are actually made of aluminum hardened with a few percent of beryllium and scandium. Super lightweight but a bit stronger than most common grades of steel.
…and I bet no one told the workers to not breathe it in to keep it a secret (like the poor folks in enrichment facilities who were told not to keep too many buckets of liquid close together…. but not why…)
Beryllium sounds absolutely awful to machine. I'm guessing the dust would be toxic...and probably explosive too.
@@Alexander-the-okExtremely toxic. As in "you were around someone who machined some without protections, your house needs decontaminating, your car will be taken away by authorities and disposed on, the workshop will be closed down, and you may never work again due to lung damage" toxic.
Not a hypothetical
@mumblbeebee6546 oh we were warned it was beryllium or an alloy thereof, the prints just had cryptic part numbers that gave no indication of what they were for but the general shape pretty much told the tale for the sa parts. The mirrors and stuff for satellites and such were far more interesting though. Yup the stuff is truly awful from a machining standpoint, got to get the speeds and feeds just right, too fast and it cracks, too slow and it takes chunks out feed too light and it eats the edge right off the insert, too heavy and it breaks the insert the part or both. Combine the work hardening of titanium with the brittleness of cast iron and you got beryllium. 💀💀💀
JWST primary mirrors are made from beryllium with a thin gold coating.
Very minimal expansion coefficient , so the mirror alignment won't need massive corrections
Soviet R7 used measurement and correction ground stations. But the first generation of R7 was more of a technology demonstrator or stop-gap solution than weapon system
Later rockets used vacuum tube computers on board, with miniaturized vacuum tubes which had a size like a small part of the pencil and a lifetime from several minutes to several hours.
I need to try and find some good source material about the soviet rockets.
I certainly am not surprised later models used miniature vacuum tubes - a lot of soviet hardware did from the mid 1960s onwards.
Can you drop any sources on the R7 guidance? Compared to USA space program the soviet one is an information black hole...
@@Feldmarshall12 There is 4 volumes of memoirs of Chertok, one of Korolev's «leutenants» with a lot of high-level information, but I'm not sure it was translated from Russian («Rockets and people»). Also, some sites in Russian were online ten years ago and I'm not sure they are still here, as links rot at an unbelievable pace :-(
But mostly paper books of memoirs not pre-printed after 80s of previous century.
@@blacklion79 I did come across "Rockets and People". Actually English translation is freely available from nasa web page (just google the title).
Do you have any idea on accuracy of those memoirs? Published in the 90's, around 30 years after, I imagine they could not be 100% accurate. As far as I understand he didn't have access to government run archives when writing, did he?
And anything published before 90's would be run through machines of propaganda and censorship, again impacting accuracy.
This is stark contrast to NASA history series, where authors were supported by access to many documents still held in archives and could arrange for meetings with people that were still in NASA at the time of writing. But maybe I worry too much ;)
I commanded a Missile Combat Crew in the early 80s. My system was Minuteman III. One morning when I was sitting in the Squadron waiting to go on alert, I happened to stumble upon an old Dash 1 Tech Order for the original Minuteman I system and started to read. I was shocked to learn that the first Launch Control system had no computer at all. The entire thing was based on mechanical relays. The Enable commands were simply electrical continuity circuits. Interrupt the circuit and the sortie enabled. If power at the capsule dropped, all the sorties in the flight would enable. Daily SCN tests dropped connected sorties into Standby mode so the crew could verify communication. The whole design was surreal to me given all the nuclear surety that was deliberately built into the software that I used. I couldn't conceive of that kind of system without a computer. But I guess it makes sense given the level of technology in the early 60s.
The computer in my capsule was a Rolm 1666B, especially built for the mission. Not much by today's standard but it did the job.
Sorry if this is a stupid question, but what was it like doing your job? I can't imagine the feeling of working next to such awesome (in the old sense of the word) machines.
@@GulmoharBloom Missile crew duty was a 24 hour alert consisting of alot of tedium interspersed with intense activity. It was cold in the capsule so I generally wore a sweatshirt. (The first thing you did on alert was take off your uniform - one of the many, Many, MANY things the movie "Wargames" gets wrong.) Taking off the sweatshirt was a good indication of how busy I was. We had daily tasks - making sure the capsule was OK, verifying the targeting info in our sorties, calibrating the missiles every now and then. Mostly we watched. "Status monitoring" was the parlance. Security, faults, maintenance, and comm.
Did I think about the possibility of war? No, not really. PBS did a documentary in 1983 called "Nuclear Outpost" at my base. One of the reporters asked me if I had nightmares about nuclear war. I said "No, I have nightmares about Two Officer Policy violations" (Being alone in the capsule was a serious offense.) I still had those nightmares 10 or 20 years after I got off crew.
That said. Just before I got on Crew, "something happened" (we will leave it at that) and the readiness of the missile crews went up to the point that they inserted launch keys. (That's a long way from actually launching missiles btw but it is still what you call a significant event.) That's only happened a handful of times in history. The command post on the base had a direct line to all the crews in the field, and the first direction was "Do not call home. Keep the outside lines clear." Everything was restored to normal in a few minutes as the "something" was resolved. Since the launch switches are sealed to prevent tampering, a lot of people were immediately dispatched to the field to replace the seals. They said the crews on alert were just white and still shaking. So, yes. We knew it was real. But it was mostly remote from consciousness.
Would I have turned that key if so directed? Yes. No doubt in my mind.
@@carljacobs1260 It just boggles my mind to meet (?) someone who would be/was involved in nuclear warfare. I'm not sure if I could have turned the key if it came down to it, but then I won't ever be in a position to do so.
Thank you for responding, it's given me a new perspective to consider as I read more about nuclear war. Have a nice day!
@@GulmoharBloomWhen the time you fictionally turned the key you would be very very willing and wont hesitate since the fcker that lauched first certainly didnt
@@carljacobs1260 Oh come on, WarGames was - technically at least - fantasty, albeit terrific movie. Was documentary you mentioned used in Gwyne Dyer's "On War" or "First Strike" or was it other?
Early computers like this are fascinating, stuff like the core rope used in the AGC, really amazing tech.
The core rope modules were wild. When they reprogrammed the AGC to use as a fly by wire computer, they had to race to write the code before the core rope manufacturing facility was closed forever.
As a very young child I got to see a core memory computer being used in production. I found it really neat that one could see where every physical bit was stored. (I've tried to determine what precisely machine it was but to no avail.)
I'm a computer nerd and have no idea what core rope or an AGC is. 😂 Thank you for what I'm sure is about to be a very happy Google/wiki rabbit hole.
@@orangejjay Have fun!
@@Alexander-the-okcode being rushed? As old as code! 😂
That magnet hard drive sounds more like a parallel-track magnetic tape loop made out of rigid bodies instead of bands of elastic or celluloid.
Wait. It's planar drum memory.
Yea, the one used for the D-17 is a drum memory. The models produced for less-extreme environments (including the Hound Dog missile) were more like a single platter hard disks. See Appendix A of _MEM-BRAIN FILE, Four versions for DCA_ for details.
I love this series on early computing history! The intersection with the more advanced weapons of war is fascinating (although very much expected); I may abhor war but its still a very interesting topic (probably because of them having to solve novel, and difficult problems), which further complements my interest in learning about early computers and the like.
I appreciate you way of relaying information in videos quite a bit too!
Studying CS, i do get a more general, and vague ish, information on early computing history, but seeing those actual examples makes it truly impressive what they had to do in those early days.
War is just too damn interesting isn’t it? It never fails to amaze me how much early computer scientists were able to achieve with so little.
@@Alexander-the-ok It's a shame that humanity seems unwilling to devote similar resources to productive endeavours.
@@alexhajnal107 War can be more productive
WW2 had a lot of technological advances
although this happens more for total wars and cold wars,the modern insurgent style wars or small scale state wars dont produce much new technology.
27:00 - Huh! The pcb’s make me think of isolinear chips on Star Trek TNG. Very cool that this was possible back then!
Might actually have been them, because prop departments often scrounged cheap surplus equipment to make props, and thus might have used them.
26:13
That's not a dodecahedron. It's a hollowed out dodecagon prism. A dodecahedron is a polyhedron with 12 faces. The prism has 14 flat faces, not counting the extra ones from hollowing it out.
This is so much not a dodecahedron.
‘Extruded dodecahedron’ is what i called it because there's no way i was going to try and say ‘dodecagonal prism’.
...on further reflection, I'm still wrong. It should be 'extruded dodecagon'. The one chance I got to say that and I still got it wrong!
I was looking for this comment. Shout out to Mr Steeves my grade 9 math teacher for very effectively teaching us shapes. I think I made an icosahedron for that class.
Actually saw one when I was studying in St. John Fisher College in upstate NY. The construction and support structure on the PCBs was impressive, support for every single component: transistors, capacitors, resistors... very meticulous engineering.
The fact that you don’t have 10x the subscribers you currently have is as shocking as it is tragic. Consistently high quality uploads spanning an hour or so in length about extremely complex topics with in-depth explanations and analyses. Unreal
Finally a channel to merge my both loves in life
Computer Engineering and Aerospace Engineering
It simply amazes me that my SSD that takes up about the same space as about 5 BIC pens, can store 136,500 times the information as a drive that took up 3 refrigerators worth of space in 1956. There have been humans alive (and in fact my grandparents are examples) that have seen this evolution in real time.
Assuming decent gyros and accelerometers, you can significantly minimise compounding error by using low-pass filters at your ADC inputs. This can drastically reduce the sampling frequency required to maintain a reasonably accurate positional and velocity vector. If implemented correctly, there is no quantisation error other than the bit depth of the ADCs, and you don't lose the contribution of any high frequency components, those get averaged into the signal by the filter.
The Hard Drive architecture isn't as confusing if you think about it as a solid state version of delay line memory.
This is an excellent comparison. The fast access loops were dynamically erased and re-written just like delay line memory.
Yes, thanks for clearing that up very solid state version of delay line memoryish of you my good sir. I know these words, individually...
@@mrsquidly6395 So before we had things like high speed magnetic storage medium for computers we needed some way for computers to retain a lot of bits of memory punch cards weren't fast enough and couldn't be written and rewritten easily. Although memory cells could be made of tubes they were very energy and space inefficient for this purpose.
So the idea of delay line memory was made. Commonly filled with mercury for its density it was a long tube with a transducer at both ends. Bits were fed in as an audio waveform at one end travels through the mercury and is read out the other end. If the bits aren't read out and fed back in to the start they are lost.
@@Jackpkmn I'm gonna have to search this up because I'm still not getting the full picture even with how well you've articulated the concept to me. I can't quite tell if I'm dumb or if you're on a level I've yet to even begin grasping.
I saw mercury and all of a sudden everytime I try to comprehend it I just keep visualising one of those old lightbulbs and It keeps throwing me off. A.D.D brains there telling me "ah, we know mercury and it's in a tube so lightbulb" I'm starting to lean towards the idea that I'm probably just dumb haha
@@Jackpkmn does the wave propagates through the mercury bounce back and forward storing the information in diminishing waves and as a result acts like a very short memory?
Hmm, also if not, i thought sound propagates faster in denser mediums?
What does the delay serve?
The Soviets used a ground-based guidance system in the R-7, the basis of which was copied from the Germans at the end of World War II. The R-7 ICBM was tested in the Northern Urals in 1959 and there were some casualties there during the testing phase, including the members of the Dyatlov group who were involved in the testing and evaluation process. They conducted these tests with active warheads set to a lower yield of 1.6 megatons (standard RDS-37 warhead). After completing the series of tests, the R-7 was officially handed over to the Soviet missile forces in 1960.
For those interested in more details about the Dyatlov Pass Incident, I recommend watching my videos about the entire case and its complete solution.
Playing Doom on a nuclear missle sounds a bit too close to actually summoning an army of demons into the world.
lol, I can't believe a right-winger made me laugh without having to fear our future. Thanks!
@@ryanreedgibson I can do both 😁
Guess you wont like the idea that they play doom on the large colider now days 🤣
I work with inert gas gloveboxes a lot. The embedded controller in most of them is just a glorified MS-DOS machine. So yes, I played Doom on one of them once. With the keyboard and mouse being in the glovebox. We have USB passthroughs at the back of the thing, so that we can run things like UV spectrometers under inert conditions.
Right Wing Safety Squad - and THAT is supposed to be a Bad Thing?
I really appreciate the shoutout to Hal Laning. Besides doing the real-time OS for the Apollo Guidance Computer, he created the first compiler. People often credit Grace Hopper for that, but what she called a compiler was more like what we could call a linker today.
She did develop FLOW-MATIC which led directly to COBOL so she can be credited/blamed with creating the first high-level language for business applications, usable by people without any training in mathematics. (Guess whose work led to FORTRAN though.)
@@alexhajnal107Plankalkül?
@@peterfireflylund I was referring to Laning whose work directly influenced the design of FORTRAN.
It's kind of annoying that Hopper is remembered in popular parlance for the compiler....and then everyone has to point out it's a semantic quirk and she didn't technically invent it. Because she did SO SO much more than just invent the linker. She was an excellent presenter/orator too....I imagine she'll appear in one of my videos in the future.
Giving Hal his due does not reduce Grace Hopper's legacy by any noticeable degree. She and Margaret Hamilton were and are (respectively) towering figures casting long shadows, ironically given both stood only a little over 5 feet.
When you pointed at the need for high precision of guidance and possibility of corrections (22:07), you mentioned missing St. Petersburg and hitting Helsinki. Well, at the time the minuteman were developed and were operational it was Leningrad they were aiming at, since the name St. Petersburg was reissued only after the collapse of Soviet Union
I don’t think this correction is a must, but I figured it would be something to note
Great point. I never thought of that.
Thus Lt. Chekov in Star Trek had scotch "invented by a little old lady in Leningrad." How were the Star Trek writers to guess it would change back to Petrograd by then?
@@sciptick
There are people born in towns which changed their name upon independence.
But they speak of the place where they were born, not what some politician called it later.
Sometimes an international airport changes its name but the codes for that location are still the same.
There is one 50 miles from here but a Liberator pilot would use the same name. As would a local.
The D-17B used discrete DRL (Diode Resistor Logic) circuitry with DTL (Diode Transistor Logic) where needed, but the MMII used the D-37C which was one of the first guidance computers to use SSI integrated circuits (The other being the Apollo Guidance Computer).
Amazing video, thanks!
Storage time: 10 years
Operating time: 15 minutes
Operating environment: 10G's
IIRC beryllium is a very stiff metal for its weight. It's also used in the JWST mirror segments for the same reason. Probably also has a low coefficient of thermal expansion. Nice modern IMUs still output an integrated delta_v over their sampling interval as well.
You have no idea how much I enjoy this video. I have always been fascinated by early computers. Back when I was in school and briefly after, I only had time to read *a little bit* into these computers. Here, you've gone *all the way!!!*
Thanks. Tbh I'm the same - always been fascinated by early computing, but only recently had the time to study these systems in more depth.
I am looking forward to the episode about the Navy's fully-networked, transistorized refrigerator-sized missile fire control computers, put into operation in ~1964. It is one thing to equip a computer to work control surfaces and thrusters, another to have it swing a robot arm into position and launch missiles. Many ship captains got into hot water trying to keep the computers off their ships, but the need for fast response left no possibility of them staying in the loop. Where more capacity was needed, they added more of them, and all talked via radio link to their counterparts in nearby ships to coordinate their activity. So a missile battery on a destroyer could be used to protect a nearby aircraft carrier, without crew help.
I gather those machines had a role in Apollo as part of the worldwide communication and tracking system, but the details escaped me.
Alexander, you consistently impress me with your focus, dedication and contextual research - and yet you are brilliant at presenting, storytelling and not to forget, visual humour where possible. I wish I’d had professors and lecturers like you! Thank you for sharing your work with us!
Dow Chemical developed a process control system in house called the Mod5. I don't know if it used a D17, but I do remember the processors were repurchased missile controllers. They were programmed with a Dow specific version of Fortran jokingly called Dowtran.
you and Artem Tatarchenko are a match made in heaven lmao. he is so talented and really adds a lot to your really well written and interesting essays :)
Agreed, he's amazing at what he does.
While the animation is quite good, a few details do distract me quite a bit as a big fan of the Minuteman system.
The silo layout, in a forest and surrounded by buildings definitely seems more like a Soviet style missile silo installation. The US launch facilities are very spartan and remote, just a fence and dirt and gravel patch around the silo door, usually in the open plains of the upper Midwest.
Also the silo door actuator is much more violent. While a lot of footage of launches comes from the Vandenberg silos, where they slide open smoothly on rails, those silos were designed for repeated use. The actual deployment silos have a much more simple system. Hydraulic rams push with great force the concrete door on smooth metal rails with enoug energy to make sure that even if the silo is covered by dirt due to a near by detonation that it can get out of the way. The only thing stopping it is how much friction it has once it comes off the rails (and in reality could easily breach the perimeter fence).
Also the tail end renders show two exhaust nozzles. The Minuteman first stage had four nozzles fed by a single solid rocket engine.
Anyway, nitpicking but small details noticed by a pedantic nerd.
Yeah, I saw a couple of of preeecessors, probably for the Titan II, of these being thrown out from the local University. They were supposed to go to hazardous waste disposal, as they used a cooling system using liquid mercury. Really sturdy devices with inch-thick aluminum cases. You couldn’t see much inside the case as it was filled with plastic foam. Wish I had kept them.
I'm still kicking myself for not rescuing the DEC PDP that I saw in the trash outside a medical office in the early naughties.
@@alexhajnal107 I had the opposite experience-- I bid on two PDP-11/44 systems, won them, then found out they were just the cases, someone had pulled out all the cards.
There is a VERY tiny subset of the human population who can appreciate the near-erotic beauty of those circuit boards, with their intricate runs & tightly-packed, imminently symmetrical & intimately considered component layouts. I belong to this group. Thank you for sharing those images. I want to get one of those boards under a microscope, but I know this is as close as I’ll ever be. It’ll have to be enough. Thank you.
jeezo, RUclips is hammering this with unskippable pairs of 20-second adverts every few minutes. I'm using a VPN so they're unintelligible ads for (I think) Danish supermarkets but I keep needing to mute
Sorry, youtube went crazy with automatic ad placement a couple of months ago. I've just deleted a bunch of them.
Man your videos get better and better. Thanks so much for sharing!
Alexander, this is a very interesting video. I used to work with a very early DCS, it was designed and built by the company that used it in its pharmaceutical manufacturing business as process control and batch reporting. I only had a bit of time to learn about it before we replaced it with a modern standard (S7-4xx).
I specifically recall an analog input board with hard-codeable limits (DIP switches and jumpers, 8-bit, low and high warning and alarms, it triggered an interrupt on the central and fed it to a card managing all the interrupts and their privileges.
It was a headache to implement the interrupts as the only documentation we had was a copied copy of someone’s handwritten notes that had been used during qualification and then copied again and put in a binder.
It worked for decades but there was a fatal flaw in the design and it hadn’t been picked up. It was quite the hassle to get the HAZOP reviewed by the chemist who just muttered „boy, we were very lucky“ and then update the documentation to reflect the corrections we had to make.
Fun.
How far is your SDS and the SMDS for this project? 😏
Keep it coming, love it!
Beryllium is super lightweight, super strong, and has a very low thermal expansion coefficient, so parts made from beryllium alloys can be made with tighter tolerances than aluminum or titanium. There's also no risk of sparks or static buildup, which can reduce compounding errors in inertial guidance systems. But... beryllium poisoning is absolutely horrible, it makes asbestos seem like a mild nuisance in comparison
Congrats you've made one of the best RUclips videos of the year
I really appreciate your calm and clear narration!
Oh never expected to see you using godot while I'm making hobby game with godot as I watch!
And as a CS Student who had 'not so good time' with SPARC and MIPS, I was really surprised to see 48:20 Instruction bit mask and it's naming were basically same since that long ago.
Truly we were just using an improved version of D-17b guidance computer! Amazing video, now this one's my favorite.
"Can it run Doom?"
"Oh, yes, it most definitely can."
Of course, the only winning move is not to play.
With flying colours.... so to speak....
The tethered missile tests apparently were conducted with dummy second and third stages, and I believe the tether was to pull the missile away from the silo, avoiding damage. Cheaper than special hardware for one test.
Thank you for programming the simulator. As a programmer myself, I have an idea of the effort required!
Thank you ever so much.
Thank you for another awesome instalment to your growing long-form content library. I love the low level tech on here- please continue with the magic jazz :)
Gotta say, I love your use of my favorite Chopin prelude in the intro. It fits so well!
I can't express how much I enjoyed watching this go over my head.
Coming from an audio guys perspective, I would guess beryllium was used for its unique combination of high stiffness and low mass, plus the fact that it’s really good at damping high frequency and thus would make the system less susceptible to feedback from vibration.
Beryllium is used exactly for these reasons in über high end tweeter cones
The computer was under the platform that carried the RVs. It also had either an electrostatically levitated sphere gyroscope or a helium neon 6 axis ring laser gyro in the dead center. The main middle battery was a 28V NiCd battery but the ones in the actual nukes were magnesium based thermal batteries. What they got in the more modern ones is a lot smaller and more accurate.
I really want to do a segment in a future video on ring laser gyros.
Great to know the D-17 got put to good use. The Minuteman boosters are also getting a new life as part of today's satellite launch vehicles!
You mean the old solid propellant stages? That's pretty cool, also insane they got that long a shelf life.
this is _such_ a good channel, good lord.
Classic music and Minuteman missiles truly a blend for the end times.
on the very brief note towards the beginning about disconnecting the device from the purpose. that’s a big deal for me as someone who has plenty of ethical and philosophical things to say about war & politics (I mean who doesn’t, right) but also *loves* military technology, history, theory, etc. always been drawn to that stuff since I was very young, so taking the hate and tragedy from something’s existence and putting it to one side is a critical part of enjoying things I’m passionate about. and of course it makes videos like this possible. glad I found you this morning.
I love when people learn about the fundamentals of computing. It's so awesome that you can program anything with just the base building blocks of either NAND or NOR for logic constructions
This video has made me wanting a D17 replica!, (probably an arduino is overkill but it would be way cool having a 3d printed chasis, and wired ports to do electrically equivalent terminals), just to show off driving a 3d printer with an ICBM.
not a dodecahedron (which is the standard 20 sided die used in games) but a dodecagonal cylinder (12 sided polygonal cylinder)... great video, the names of some of the companies and projects brings back some early memories of my career... keep up the good work...
A machine born out of pure hatred, finding a new life teaching the next generation. A poetic metaphor for so many things wrong with the world.
Another great video as always! Appreciate you putting so much effort and attention into your work, keep at it!
40:29 I'm an analytical chemist, so I can see the utility of using a computer to extract information from AutoAnalyzer data. I would guess it would boil down to solving systems of linear equations, something the D17B would excel at.
If not mistaken, the first computer on russian lauch rockets was the s-530 on the 4th and last N1. As far as ICBM, someone knows?
Before that it was a program cam
This thing is totally badass, it's like a micro CRAY the way it's C shaped.
5:22 The historic sequence of an operator at a console, I presume a first response operator simulating a launch initiation, is remarkably similar to the opening sequence of "Wargames". This is not surprising, as that was set in a first response bunker. But usually Hollywood gets a lot very wrong, in that case the actions shown in the historic video are almost point for point the same as the movie.
21:30 That is trivial. The explosien caused a massive leak that bypassed the thrust nozzles completely. Thereby reducing the thrust not to nul but to a fraction. That influence sufficed to control the terminal velocity.
That’s what I initially thought but all the sources on this state it wasnt a thrust bypass but a near instantaneous termination as the reaction abruptly stopped.
A few other viewers have clarified its because the rapid drop in pressure blows off the top layer of fuel and stops the reaction.
@@Alexander-the-ok if you cut solid state fuel fast enough until reacton gets there...
I only understand about 20% of this, but I love listening to your voice while I work.
Thanks for this interesting bit of history. I studied electrical engineering at Auburn University from 1966 on and those studying aerospace engineering had an advantage over us. At least one of those free computers from the USAF were passed along to them.
When I first realized, that I needed a computer, it was a Commodore +4 on display in a highstreet bookshop window, in 1984. -Now, if you know about the Commodore line of computer models, you might be going "Oh, no poor Jim. Not the Plus/4!", know it then, that at that time I was thirteen years old, and anything like a great looking computer would have to get funding, and to get funding the project would have to get approved by my father.
I did not get a computer before three years later, as my father; a geologist believed in "the human faculty for calculation far exceed that of such a toy".
When my father saw what I could do with my first computer he was not impressed, but when I upgraded to an Commodore Amiga 500 and showed him what I could paint in DeLuxe Paint 3, he bloody well went and bought me a RAM expansion, that cost the same as the computer.
I have told him, time and time again: You should have funded me, in 1984, and he figured so himself.
The US Department of Defense must be the cool dad; "I hear that you lads would really like to get to grips with programming? Here's a pick from the bargain bin"
Any computer is leagues ahead of calculating with pencil and paper.
Thanks for posting about that ground breaking machine :3
For anyone interested in programming, the plus 4 was a very nice little computer. Good for coding.
I had a plus 4 too! My mate had a Commodore 16 until he got the 64 later. Hilarious how long it took to load a game by cassette
It get’s to me, how well you know what questions im asking while watching. You really know your audience l.
@Alexander-the-ok I would love to see a video on SM-3 and especially all the different (or one of the) kinetic kill vehicle programs. Not sure if that is a realistic video idea since SM-3 and the EKV-derivative warheads are still in service, so I imagine details on the design of any of the EKVs are difficult to come by.
Absolutely unconfirmed at this stage, but an EKV may make a cameo in the next video.
I may well do a segment on EKVs in a future video, but there isn't really enough info out there for me to do a full video (I looked into the idea a while back).
@@Alexander-the-ok Cool, thanks!
Interesting video! Sat through the entire thing :) Amazing work!
You say there is one in the Computer History Museum? A “nightmarishly difficult restoration project”? I have a funny feeling that it sounds like an open challenge for certain electric bunny themed channel or maybe a space hardware obsessed Marc’s channel in the future.
Great to know that there are still some extremely obscure, but historically significant computer artefacts left to dig into over the following years.
Cheers!
47:29 Ehh, a dedicated accumulator register is afaik really only a feature of ancient CPUs and their direct descendents (e.g. x86). More modern CPU architectures pretty much always just have a bunch of general-purpose registers that can be freely used as source/destination register operands for arithmetic instructions. The only recent architecture I'm familiar with that uses separate registers for various roles is a DSP, but it has not one but 16 accumulator registers.
Drum computers were quite popular in the day. There are lots of examples of later systems.
Just like the real minuteman(men with muskets), it was never intended to be used, but only at the direst of times. The minuteman have made sure, we dont have to use them. That is a victory by itself.
Anither excellent video, thank you for putting it together.
27:36 the first integrated circuit was created in 1958 by an engineer at Texas Instruments who created the first ic based computer in 1961.
“ 1961 Jack Kilby's colleague Harvey Cragon built a demonstration "Molecular Electronic Computer" for the US Air Force to show that 587 TI ICs could replace 8,500 transistors and other components that performed the same function in a conventional design.”
Excellent - was thrilled to see this out ❤❤❤
I knew that, at that time, inertial navigation systems did work fairly well on aircraft, at least at relatively short distances.
Using it on an ICMB (a solid fuelled one, no less) was a completely different ball game, as beautifully explained by this video.
One could be forgiven for assuming that, because it dealt with a much less dense atmosphere for most of its flight, aerodynamic deviations would be lessen. But it isn't necessarily so. Flying at low altitudes, at a more or else constant density, even while prey of wind vectors, should likely be an easier problem to tackle with late 50's and early 60's systems.
I think you are right about one person getting credit. You would think from some documentarys that Kelly Johnson for instance designed and built the SR-71 all by himself. Plus many other planes.
This is the most interesting video on youtube!
Amazing content, so many engineering channel videos just sound like Wikipedia article reads, but you go far more in depth and hold my attention the entire time!
Just for fun, I wanted to know how fast Doom would actually run on a D-17B as the CPU. There's no way it could store Doom on it's HDD. It probably can't drive a raster display either, so let's assume some IO upgrades to handle those parts. So here's my SWAG:
According to a post on the Doomworld forums, a user estimated that Doom needs 32 instructions per pixel, so we'll use that. He mentions that the 32 instructions are on a 486, so it's likely not the simple instructions the D-17B has, but I'm not going to dive into the Doom code to find out exactly what was used. Wikipedia lists the timing for the add, multiply and load instructions, so I'll arbitrarily use those. I picked an arbitrary mix of 10 adds, 12 multiplies and 10 loads. The wikipedia page says we can do two multiplies as the same time, so we'll do the timings that way. All told, we end up with a single pixel taking 4.8 milliseconds..
Assuming my guess about 4.8 milliseconds is right (which is probably wrong), we get the following:
Doom runs at 320x200, so rendering a single frame takes 310 seconds or just over 5 minutes. Doom runs as 35 fps (ideally) so 1 second of Doom takes about 3 hours to render..
The fastest listed speedrun of Doom is 4 minutes and 39 seconds. That speedrun would take 35 days on a D-17B.
Love it thanks for this!
There is one thing missing, and its the main reason i never coded the timings into my sim: read write to the disc.
Much consideration is given to this in the original programming guide as reading from a ‘sub optimal’ sector would need us to wait up to 10ms just for the drive to rotate to that sector.
I have no idea how much more time we’d need to add in for read/write. But every time a variable is read in incurs a minimum of about 80 microseconds.
Talk about putting thins in perspective.
My favorite word for this kind of rough approximation is 'guestimate' (noun to that would be a guestimation). It isn't my creation, but I can't remember where I first came across this.
Doom would take about 18 minutes to run.
Can’t wait for that Polaris vid!
Thank you for another extremely professional, extremely interesting video. Your nickname (while very funny) doesn't do your content justice.
Do you also publish on something like Nebula or similar? Your content is definitely good enough for that, and the amount of ads RUclips is showing right now on everything makes me want to quit youtube forever (it is literally just your channel and *very* few others that keep me here.)
Thanks.
You've just reminded me - I've just gone and deleted a bunch of ad breaks from the video. RUclips's automatic placement is very....liberal.
I do publish ad-free videos on Patreon, but it wouldn't be good value for money compared to something like Nebula where you'd get way more channels. I've not even thought about Nebula - if the opportunity presents itself I'd consider it (I just do this as a hobby alongside a full time job so I don't really think very hard about monetisation etc).
Btw, when I want to watch long videos ad free, I just download them using a third party service.
@@Alexander-the-ok For a pure hobby project the quality of your research and production is quite amazing. I have long been thinking about Patreon for a few channels, maybe I should finally just do that. (That'll have to wait a few months though.)
The fact that the missile could compute its location in 3d space on a globe with just gyros.. I mean it sounds right algebraically, but how tf did they manage to do it so accurately while strapped to a fucking rocket? All that rattling around..
We take GPS for granted now and I can see why the military was so interested in restricting civilian use of it in the early days. No one, short of a superpower, was going to be able to machine a guidance system so precisely. Without that hurdle though, it’s probably magnitude easier to make a functional icbm
The 3rd stage termination shapes charges "switched off" the propulsion, by allowing the motor expansion gas to go everywhere following the path of minimum resistance, but not through the narrow, high resistance, rocket muzzles. Resulting in a lost thrust for the whole rocket
equal to an engine shutdown in a liquid propellant rocket.
The solid propellant was designed to be sufficient for max possible distance, any release of pressure, due to detonation, shortened the ballistic curve
That intro 👌
Goes hard
51:06 Actually, if we're allowed to clobber those two unused middle bits then split add/subtract is particularly simple:
split add: accumulator = (accumulator & ~0x1800) + (operand & ~0x1800)
split subtract: accumulator = (accumulator | 0x1800) - (operand & ~0x1800)
This is assuming 2's complement representation is used... I'm really not sure why you went with sign-magnitude considering 2's complement is the native format of both the D-17b and modern computers (for signed integer/fixed-point arithmetic), using sign-magnitude seems like it would just make arithmetic way more complicated to implement than it needs to be.
The disk working as register reminds me of a bendix computer usagi electronic are working on.
Awesome videos bro, well done 👍
Really amazing work. The entire video was interesting & enlightening. And the Godot work was the icing on the cake. Thank you!
17:30 - Only the Atlas D used this particular type of guidance system, the Atlas E and Atlas F used a fully internal inertial guidance system just like the Polaris, Titan II and Minuteman (Although its' guidance and control circuitry was all analogue).
A very fine history of the whole topic of guidance is Donald MacKenzie's Inventing Accuracy: A Historical Sociology of Nuclear Missile Guidance (MIT Press, 1993), a bit pricey in print these days but available on the Internet Archive
Thanks. I’ll read that before I do my video on Polaris in a few months.
@@Alexander-the-ok I'm going to second the comment above. I actually came to post about inventing accuracy, really fine book that i assign in an engineering course that I teach.
This was one of the most interesting vids i have seen for ages. here is a small sum of money.
Thanks very much!