@PHILG2864
Fascinating video Scott. I'm still an active assembler programmer of 47 years and I fully understand the principles here but cannot imagine the pressure these people were under to get the updates right first time. Supporting old systems can be a nightmare but a barely-documented 50-year-old target with one chance and an agonisingly slow turnaround time? These people repaired the finest artefact in human history - heroes, every one of them 🙂
@laserjock509
I guess hardwiring volatile RAM to a nuclear generator is one way of turning it into non-volatile RAM.
@stevebunes9151
gobsmacked! The detail in this description of the debugging and correction is fantastic. As a hardware engineer and assembly language programmer way back in the initial eight bit uP days, what was described was simply incredibly tedious. I wish everyone could appreciate just how incredible this story is.
@wewillrockyou1986
Sending commands up to a Voyager probe and then going home for the weekend to wait for it to ping back must be the worst sleep anyone can possibly get...
@PaulLoveless-Cincinnati
This episode will be viewed 40 years from now and still be as cool as it was today.
@Creadence
One correction to the text (spoken). The unit uses "Static" (SRAM) memory not "Dynamic" (DRAM). At this point Dynamic was not used (or maybe not invented yet). These are both silicon bases, but one uses active transistors (about 6) to latch the value of each bit each time is is written to. Dynamic memory uses charge wells to store a charge for each bit. Both will loose data if power is lost (volatile). Static require more power as the transistors need to conduct current to maintain the state (correction: this is CMOS so it is true, it is not much, A bigger issue is with running the RAM, each access requires more transistors to toggle and hence more current (CMOS works this way, TTL does not). Dynamic is much smaller and uses less power, but require periodic refreshing of state (the charge state in the charge well). These charge wells are very weak and would be more susceptible to upset than SRAM (especially in the earlier version due to larger wells than we use today). See the CD4061 title for the part.10:43. Minor nit, and does not change as the focus was on magnetic core memory VS solid state (silicon, or some other semiconductor).
@RogerGarrett
As a long-ago assembly language coder who PEEKed and POKEd my way through other people's code with next to no documentation I THROUGHOULY ENJOYED this entire video. I do understand how this video might not have gotten the same level of viewership as your other videos. Delving so deeply into the problems and solutions, which no doubt is beyond most of your followers, likely loses them somewhere along the line of all the explanations. But I hope this doesn't dissuade you from doing similar deep dives in the future. Videos like this will no doubt be used by educators and viewed by engineering students far into the future, showing not only how valuable engineering is and engineers are but how enjoyable finding solutions to seemingly intractable engineering problems can be, making a career in engineering a thoroughly rewarding life.
@mrmiketopping
Thanks Scott for providing real technical detail, not the dumbed-down public version we normally get from others... Great job.
@TheSomedrewguy1
This is quality content. Imagine if the youtube algorithm would prioritise this kind of work.
@stevebunes9151
I hope everyone realizes how absolutely spectacular the voyager program was and is. Simply unreal human achievement! Engineering genius at its finest. Pretty much pre powerful micro processors and ultra high speed and high density semiconductors. Simply amazing
@gregf9160
From a Software Engineering perspective, this is heroic 🤩
@bellutta
I worked at JPL for 25 years, 15 of which driving rovers on Mars. The best part of working there is seeing how anomalies are handled. I was part of several of these (Purgatory and Spirit at Troy to name two) and it was absolutely fascinating seeing how you can use telemetry and commanding to figure out what's going on and find workarounds. The science return is surely impressive but as an engineer, I am thankful for having lived most of my career in such an awesome time and place.
@c7042-u5g
I was young and still had my wife when Voyager 1 was launched. I remember the National Geographic issue on Voyager. I'm almost 76 now and am still here like Voyager 1 is still there.
@stevemurray2003
For those of us starved of technical detail, that was a hearty meal! The V1 team did an incredible job bringing it back to life.
@RonSparks2112
As a once upon a time assembler programmer, I found this video utterly fascinating and totally remarkable. Excellent work, Scott.
@tlskillman
When in college I wrote code for the Solar WInd Experiment on I-SEE 3 spacecraft (Ogilve & Coplan GSFC-UofMD). CPU was an 1802, used because it was developed for radiation hardness. What a weird architecture, mulitple internal registers, any of which could be selected to be the program counter (pointer to next instruction). All coding was in Assembly language. They slowed the clock down to keep well within the CPU's spec. The code ran the Wein Filter that was the heart of the solar wind detection experiment. It set up and swept the voltages to select out and count particles based on their mass-charge-velocity. The counts were periodically read out of and move to the telemetry buffer where the data was shipped down to Earth. Great fun to watch this video and be back living in those primitive coding days, 50 years pre-AI ! Thanks Scott.
@DaveInPA2010
As you signed off, I was weeping. Thank you Scott. Godspeed, Voyager I.
@semidemiurge
The amount of research and effort required for this level of detail and insight is truly impressive. This is as good as it gets. Thank you
@Shantara11
Voyager 1 and 2 are among the humanity’s greatest achievements! The more I learn about these missions, the more incredible they become!
@stevenzawacki