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Comment by Phlarp | Hacker News Reader

That's insane. A 3d matrix of ferrite rings suspended by wire would seem (to me) somewhat sensitive to vibrations or gforces.

Military gonna military I guess.

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For airplanes flying at high altitudes with modern computers, random bit flips from comsmic radiation is actually a very real threat that has to be considered. IIRC there's about a factor of about 300x more radiation at 30000 ft and 900x at 60000 ft.

Core memory is a lot less sensitive to this than most memory types, so it makes some sense to store the most flight critical data in such a memory.

The sensible way to deal with bit flips is a gratuitous amount of ECC.

ECC doesn't help when you have an EMP caused by an atmospheric nuclear detonation. Those are the kinds of things the design has to consider.

Makes me why we don’t count NASA under DoD similar to DARPA to help with their funding.

NASA exists to be the civilian side of the US’s aerospace ventures. The military side is the Air Force.

> NASA exists to be the civilian side of the US’s aerospace ventures. The military side is the Air Force.

Not the Space Force?

> https://www.buzzfeednews.com/article/briannasacks/trump-spac...

;-)

The point of NASA was to create an agency for non-military aerospace development, while ARPA was supposed to handle military applications.

I think Eisenhower thought that this would insulate NASA from postwar budget cuts and make its funding more secure rather than less.

In retrospect, Eisenhower was a hell of an optimist.

In addition to NASA's explicitly non-military nature, we do actually maintain some relationship with our USAF counterparts. When it makes sense to do so, we're happy to work on mutually beneficial projects.

But wouldn't that fuck up the processors as well as memory anyway?

In flight reboot

Depends if the vacuum tubes are shielded. ;)

or a lead liner? I know lead and aircraft don't mix, but a thin lead shield over just the computing boards shouldn't add too much weight, should it?

The same technology was very successfully used to fly to the moon. Cores aren’t so much suspended when they are wholly embedded in epoxy.

Stupid question, but the cores don't physically flip, do they? It's a purely electrical thing?

Yes

It's the magnetic field that flips, the ferrite cores remain in place

I think it's just clockwise vs counterclockwise.

But on the other hand core memory is very resilient against EMP and hard radiation :)

I seem to recall something along the lines of large bombers running valves as they were less prone to effects of EMP around nuclear blasts. Not sure if this perhaps something similar?

In one of the documentaries about the Vulcan raid on the Falklands (1982), one of the pilots interviewed remarked that somebody flying Avro Lancasters in WWII would have felt right at home in the cockpit of the Avro Vulcan. E.g. the navigator used mechanical clocks to keep track of when to turn, and so on.

Not sure if this was a conscious decision wrt EMP, or was it just that they were in a hurry to develop a jet bomber for delivering nukes and they reused existing stuff as much as possible.

Not in the least surprising. The Vulcan prototype, the 707, first flew in 1949. They even had a mount for the old Lancaster bomb sight - though that was mostly used for a camera.

Flight engineer and radar operator in the seats behind would have got the fancy new (for the early 50s) electronic things.

The Lancaster was loaded with the technology of the time by the end up the war e.g. they had radar navigation, radio navigation, (when it worked) a 'lock' detector for German night fighter radar

Which documentary was this? I read Vulcan 607 about ten years ago and loved it.

I'm quite sure it's this one: https://www.youtube.com/watch?v=PBJ99bIhAVk

From wiki for the MiG-25:

The majority of the on-board avionics were based on vacuum-tube technology, not solid-state electronics. Although they represented aging technology, vacuum tubes were more tolerant of temperature extremes, thereby removing the need for environmental controls in the avionics bays. With the use of vacuum tubes, the MiG-25P's original Smerch-A (Tornado, NATO reporting name "Foxfire") radar had enormous power – about 600 kilowatts. As with most Soviet aircraft, the MiG-25 was designed to be as robust as possible. The use of vacuum tubes also made the aircraft's systems resistant to an electromagnetic pulse, for example after a nuclear blast

Well, at least in that case it seems like a conscious design decision. Not sure how much of the state of the art design and tech was driven by "I like the colour" or "the supplier is in my state".

The Soviet design bureaus certainly had their irrationalities. They behaved like big, vertically-integrated companies, and preferred 'their' stuff over the other design bureaus' stuff.

Soviet gear was robust because robustness and repairability was priorities as a design criterion. It's not an automatic product of how they doled out work, or of their defense industry generally.

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