Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Apollo 11 vs. USB-C Chargers (2020)

forrestheller.com

Post reply on HN
Print view View original

41–50 of 209 posts

Re: Apollo 11 vs. USB-C Chargers (2020)

#41

Post by ajsnigrutin »

codezero wrote: post #35

Weird question maybe, but does anyone keep track of quantitative or qualitative data that measures the discrepancy between consumer (commercial) and government computer technology? TBH, it's kind of amazing that a custom computer from 50 years ago has the specs of a common IC/SoC today, but those specs scale with time.

There is no difference anymore, the only difference is the scale.

Back then, consumers got nothing, governments got largge computers (room sized+), then consumers got microcomputers (desktop sized), governments got larger mainframes, consumers got PCs, government got big-box supercomputers,...

And now? Consumers get x86_64 servers, governments get x86_64 servers, and the only difference is how much money you have, how many servers can you buy and how much space, energy and cooling you need to run them.

well, "normal users" get laptops and smartphones, but geek-consumers buy servers... and yeah, I know arm is an alternative.

Re: Apollo 11 vs. USB-C Chargers (2020)

#43

Post by mcbutterbunz »

dikei wrote: post #34
jojobas wrote: post #21

Earlier quoted context omitted.

That sounds way too low. Modern fly-by-wire planes are said to have 12-way voting.

It's more complicated than that, in the link, they described it better: >> The microcontrollers, running on PowerPC processors, received three commands from the three flight strings. They act as a judge to choose the correct course of actions. If all three strings are in agreement the microcontroller executes the command, but if 1 of the 3 is bad, it will go with the strings that have previously been correct. This is…

I’m curious how often the strings are not in agreement. Is this a very rare occurrence or does it happen often?

Re: Apollo 11 vs. USB-C Chargers (2020)

#44

Post by c0pium »

codezero wrote: post #35

Weird question maybe, but does anyone keep track of quantitative or qualitative data that measures the discrepancy between consumer (commercial) and government computer technology? TBH, it's kind of amazing that a custom computer from 50 years ago has the specs of a common IC/SoC today, but those specs scale with time.

Why would you expect there to be one? It’s all the same stuff and has been for decades.

Re: Apollo 11 vs. USB-C Chargers (2020)

#45

Post by nothercastle »

hinkley wrote: post #38
nothercastle wrote: post #28

Earlier quoted context omitted.

Exactly this. A lot of the systems had built in analog computers. It’s a lot cheaper to build then now with electronics but you need more computing power to do things that were previously done mechanically

Analog computers have to be rebuilt if it turns out the program is wrong though, don’t they?

Yes though they tend to be mechanically tuned. So like a pneumatic computer or will get tuned to operate into some range of inputs and you probably bench prototype it before you mass produce it

Re: Apollo 11 vs. USB-C Chargers (2020)

#46

Post by etrautmann »

p-e-w wrote: post #36
jojobas wrote: post #21

Earlier quoted context omitted.

That sounds way too low. Modern fly-by-wire planes are said to have 12-way voting.

I don't understand this. If two or more computers fail in the same way simultaneously, isn't it much more likely that there is a systemic design problem/bug rather than some random error? But if there is a design problem, how does having more systems voting help?

The multi processor voting approach seeks to solve issues introduced by bit flips caused by radiation, not programming issues.

Re: Apollo 11 vs. USB-C Chargers (2020)

#47

Post by coder543 »

hinkley wrote: post #38
nothercastle wrote: post #28

Earlier quoted context omitted.

Exactly this. A lot of the systems had built in analog computers. It’s a lot cheaper to build then now with electronics but you need more computing power to do things that were previously done mechanically

Analog computers have to be rebuilt if it turns out the program is wrong though, don’t they?

In the context of this thread, I believe even a digital computer would have to be rebuilt if the program is wrong... :P

Unless you typically salvage digital computers from the wreckage of a failed rocket test and stick it in the next prototype. If the FCC is wrong, kaboom.

Re: Apollo 11 vs. USB-C Chargers (2020)

#48

Post by oldgradstudent »

ssgodderidge wrote: post #29

> The Anker PowerPort Atom PD 2 USB-C Wall Charger CPU is 563 times faster than the Apollo 11 Guidance Computer Wild to think the thing that charges my devices could be programmed to put a human on the moon

> Wild to think the thing that charges my devices could be programmed to put a human on the moon

With a large enough lithium battery, a charger can easily take you part of the way there.

Re: Apollo 11 vs. USB-C Chargers (2020)

#49

Post by etrautmann »

petermcneeley wrote: post #39
AnotherGoodName wrote: post #10

Pretty much all USB chips have a fully programmable CPU when you go into the data sheets. It feels silly for simple hid or charging devices but basic microcontrollers are cheap and actually save costs compared to asics.

I would also argue that this is another example of software eating the world. The role of the electrical engineer is diminished day by day.

Nah - there are lots of places where you need EEs still. Anything that interfaces with the world. Having programmability does not move most challenges out of the domain of EE. Much of it is less visible than the output of a software role perhaps.

Re: Apollo 11 vs. USB-C Chargers (2020)

#50

Post by adgjlsfhk1 »

vlovich123 wrote: post #12

Is the weight/cost calculus sufficiently improved now that it’s cheaper to shield the processor in it’s entirety rather than trying to rad harden the circuitry itself (much more expensive due to inability to use off the shelf parts & limits the ability to use newer tech)? If I recall correctly this was one of the areas being explored by the mars drone although not sure if Mars surface radiation concerns are different…

one thing worth remembering is that a bigger computer runs into a lot more radiation. the cortex m0 is about .03mm^2 vs about .2m^2 for the Apollo guidance computer. as such, the m0 will see about 6 million times less radiation.
Post reply on HN