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altermagnetism

 

This is kinda interesting:



Might kick tech up a notch or two...


--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
 

Oh, no!
Core memory is coming back!

~SD
wn4isx
 

I just threw away a 1k (1024) magnetic core plane driven by TTL. It dated from 1968. The college of engineering was tossing it in 1976 and I thought it might be useful. Wired it to a KIM-2.? It worked by what a headache
The Chyron (TV charater generator) at the university medica center had 5 core planes, stacked, they were 2 feet by 2 feet and 3k each for a total of 9k.
The 8" floppy drive was so stupid if the system issued a command change from track 20 to track 21 it backed the haed all the way back to track zero then stepped forward 21 tracks. sounded like a supressed maching gun. We replaced it with a dumb PC [original 5 slot IBM PC] with a 5meg hard file and the production people were so happy they wanted to have it's babies.
Somewhere i have several 4" squares I cut from one of the magnetic planes.
Core plane worked amazing well given how primative it was.
I hope it's not coming back.
We had a demonstration of TI's magenetic bubble memory....that crashed everytime the engineer tried ti rurn the program.
Magnets belong in compasses and children's toys,not computer memory!
 

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Your experiences sound a lot like mine.

I too have a core memory sample but without I-O electronics.

For a job, I bought two early 8” floppy drives @ $800 each in 1977.? That is $4,000 each in today’s money!

The drives were bare.? I did my own floppy disc controller and operating system.

The customer also requested a tape backup option too.? It was noisy punching the tape.

Later I did a CRT display with my own driver and character generator.

I have a hard drive monster; the platter is about 10 inches in diameter and 3/8” thick.? Yes, almost 10mm!

It is amazing to think about the changes in 50 years!

Bertho

?

?

From: [email protected] <[email protected]> On Behalf Of wn4isx via groups.io
Sent: 17 December, 2024 7:16
To: [email protected]
Subject: Re: [electronics101] altermagnetism

?

I just threw away a 1k (1024) magnetic core plane driven by TTL. It dated from 1968. The college of engineering was tossing it in 1976 and I thought it might be useful. Wired it to a KIM-2.? It worked by what a headache

The Chyron (TV charater generator) at the university medica center had 5 core planes, stacked, they were 2 feet by 2 feet and 3k each for a total of 9k.

The 8" floppy drive was so stupid if the system issued a command change from track 20 to track 21 it backed the haed all the way back to track zero then stepped forward 21 tracks. sounded like a supressed maching gun. We replaced it with a dumb PC [original 5 slot IBM PC] with a 5meg hard file and the production people were so happy they wanted to have it's babies.

Somewhere i have several 4" squares I cut from one of the magnetic planes.

Core plane worked amazing well given how primative it was.

I hope it's not coming back.

We had a demonstration of TI's magenetic bubble memory....that crashed everytime the engineer tried ti rurn the program.

Magnets belong in compasses and children's toys,not computer memory!

_._,_._,_
 

When I was a student apprentice at EELM Computers, Kidsgrove, in the early 1960s they had dozens of ladies assembling magnetic core memories. Very fiddly work!

Leon Heller
G1HSM

wn4isx
 

My wife knits and crotchets. When I saw my first core plane memory I wondered at the manual dexterity required to wire the feritte donuts. Each donut was a bit. 7 or 8 per byte, 1020 or so bytes per pane page.
And the work had to be zero errors.
?
It makes my brain ache.
?
For those young enough to not know what the devil we are talking about...
?
There are so many things about old tech I don't miss I can't list them all.
I always thought vibrator power supplies for car radio receivers were beyond stupid.
I mean, don't you want an arcing noise source inside your receiver...to jam weak signals?
And yes I know better designs didn't have arcs and 1955 tube radios are amazinginly sensitive.
But all vibrators arc at 'end of life" which might mean they only have 1000 hours of life left.
?
Or dynamotors for HV.....brushes almost always arc.?
?
I can just see some AI choking at the word vibrator.
?
OK kidies consider a 'relay' where you wire the normally closed contacts in series with the coil.
Apply power and the relay turns on and off very rapidly.?
Use another set of contacts to provide power to a step up transformer..
Instant high voltage
Then use another set of contacts that move in synch with the switching contacts and you have synchronouse rectification, no diodes required, no diode loss (and vacuum tube diodes are the definition of loss)
Said 'relays' were most often mounted in a foam lined metal 'can' with a tube like plug so it could be replaced.
That is a vibrator from 1950.
?
BTW this is still a valid way to produce HV quick and dirty, very dirty. My first home made Geiger Counter used a relay driver until I got the transistor multivibrator to work.
?
I don't know why spell check has stopped on Groups IO. Now you see the raw writtings of a dyslexic.
?
?
?
 

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It may have been primitive, but it was exceptionally reliable - used in many spacecraft and rockets and their payloads - Pioneers 10 and 11 and Saturn V come to mind.

Magnetic bubbles are completely different technology.

Donald.

On 12/17/24 07:15, wn4isx via groups.io wrote:

I just threw away a 1k (1024) magnetic core plane driven by TTL. It dated from 1968. The college of engineering was tossing it in 1976 and I thought it might be useful. Wired it to a KIM-2.? It worked by what a headache
The Chyron (TV charater generator) at the university medica center had 5 core planes, stacked, they were 2 feet by 2 feet and 3k each for a total of 9k.
The 8" floppy drive was so stupid if the system issued a command change from track 20 to track 21 it backed the haed all the way back to track zero then stepped forward 21 tracks. sounded like a supressed maching gun. We replaced it with a dumb PC [original 5 slot IBM PC] with a 5meg hard file and the production people were so happy they wanted to have it's babies.
Somewhere i have several 4" squares I cut from one of the magnetic planes.
Core plane worked amazing well given how primative it was.
I hope it's not coming back.
We had a demonstration of TI's magenetic bubble memory....that crashed everytime the engineer tried ti rurn the program.
Magnets belong in compasses and children's toys,not computer memory!
wn4isx
 

And some of those were designed with slide rules and log tables.
Now that's primative.
Although I still have, and can use, my slide rule and I have my log tables my father used when he studied engineering pre-WWII.
?
 

On Tuesday 17 December 2024 07:15:59 am wn4isx via groups.io wrote:
I just threw away a 1k (1024) magnetic core plane driven by TTL. It dated from 1968. The college of engineering was tossing it in 1976 and I thought it might be useful. Wired it to a KIM-2.? It worked by what a headache
The Chyron (TV charater generator) at the university medica center had 5 core planes, stacked, they were 2 feet by 2 feet and 3k each for a total of 9k.
The 8" floppy drive was so stupid if the system issued a command change from track 20 to track 21 it backed the haed all the way back to track zero then stepped forward 21 tracks. sounded like a supressed maching gun. We replaced it with a dumb PC [original 5 slot IBM PC] with a 5meg hard file and the production people were so happy they wanted to have it's babies.
Somewhere i have several 4" squares I cut from one of the magnetic planes.
Core plane worked amazing well given how primative it was.
I hope it's not coming back.
We had a demonstration of TI's magenetic bubble memory....that crashed everytime the engineer tried ti rurn the program.
Magnets belong in compasses and children's toys,not computer memory!
There is some talk in one of the test equipment groups (I forget if it's HPAK or Tek) about replacing some of the currently battery backed memory (currently some kind of Dallas chip I think) with what they're calling a ferromagnetic chip, so there's something of the sort out there.

I remember years ago when some of the surplus junk places would offer a core plane for sale. I never got one, but I think it'd be kinda neat to have one hanging on the wall in here.

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

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