ANSWERS : Technology

I have really wanted to do this but I could never find those pesky rings!

Comments

[seanroberts]

I think i am going to get: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330433810462&rvr_id=&crlp=1_263602_263622&UA=WVS%3F&GUID=bb6efd981260a0aad2c2bf02fff80f71&itemid=330433810462&ff4=263602_263622#ht_500wt_1154 This will work right? It will change states when current running through wire magnetizes it.

[steveastrouk]

Looks ideal to me.

[seanroberts]

What I am worried about though is if the will change the polarity of their magnetic field in the way necessary for magnetic core memory. I don't know if cores were purpose built with specific material properties but I am hoping they weren't and that all small ferrite toroids will work.

[steveastrouk]

I'll ask my father, who is an expert on ferrite properties. Steve

[seanroberts]

Thanks, that would be of great help!

[steveastrouk]

Right, I asked. "Only HARD ferrites are used for core memory - they have a virtually square BH curve. Hard ferrites exhibit permanent magnetism, soft ones don't." Steve

[steveastrouk]

If I were you, I'd look at buying some old core memory and re-energising it, rather than sewing my own. Steve

[seanroberts]

I can't find old core memory either. What do you mean by re-energizing it? Do the toroids become demagnetized or something?

[steveastrouk]

http://cgi.ebay.co.uk/USSR-Soviet-military-ferrite-core-memory-HUGE-CORES-/220616557908?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item335dc58554

[Re-design]

Too bad that one appears to have been damaged.

[steveastrouk]

Yes, but its got cores on it. The one the same guys had sold that was intact went for over 150 USD ! That means the 4 boards I have from a computer that was broken up at University must be worth a fortune by now. Steve

[Re-design]

Yes, I forgot the original quest was for the cores.

[steveastrouk]

http://cgi.ebay.com/VINTAGE-RAW-FERRITE-CORES-CORE-MEMORY-BOARD-SEALED-/300433477482?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item45f33b0f6a

[Re-design]

Gosh. Those are sure tiny little things. I'll bet the people sewing those things went bonkers after a while.

[steveastrouk]

According to some of the sources about the Apollo guidance computer, the core rope memory of the AGC was know as LOL memory, for Little OId Lady memory - it was hand stitched by, well, little ol d ladies who could follow a knitting pattern !

[seanroberts]

Ya, I heard that on a discovery channel show about the apollo missions from someone being interviewed who actually worked on the mission.

[Re-design]

I had heard something very similar.

[kelseymh]

Fascinating. From the picture, I calculate that they're exactly 1/33 inch in diameter (1/13 cm). That seems a slightly non-obvious form factor to choose.

[steveastrouk]

I mean make the old electronics work, the core should work forever. Steve

[Burf]

All of the new fluorescent bulbs I've opened up have one in the circuit board. I once saw an Instructable for opening the things up. I presume it is still available through the Search function above.

[steveastrouk]

http://cgi.ebay.com/VINTAGE-RAW-FERRITE-CORES-CORE-MEMORY-BOARD-SEALED-/300433477482?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item45f33b0f6a

[steveastrouk]

http://cgi.ebay.com/VINTAGE-IBM-MAGNETIC-CORE-STORAGE-MEMORY-PLANE_W0QQitemZ230484371620QQcategoryZ4193QQcmdZViewItemQQ_trksidZp4340.m263QQ_trkparmsZalgo%3DSIC%26its%3DI%252BC%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%252BDDSIC%26otn%3D20%26pmod%3D250637176355%26ps%3D63%26clkid%3D7982020868259349499

[Jayefuu]

Cor that sounds like a lot of work!

[steveastrouk]

Do you mean core that sounds like a lot of work ? ! Steve

[Jayefuu]

Yes but I was being coreful not to make the pun tooooooo obvious.