Bubble Memory • Hacker News Board

Re: Bubble Memory

#11

Post by alnwlsn » Wed, Aug 05, 2026, 1:19 PM UTC

rwmj wrote: post #4

bayindirh wrote: post #2

I find pretty interesting that the memory is not perfect out of the fab and its defects are coded on its label, hence these defects can be loaded to the device using it as a map, so it can work around these loops while working. Now, this is even true for flash memory, but this is handled at the controller level and its dynamic during its initial "formatting" at the factory, so it's completely hidden from the host unl…

Hard disks used to come with a paper label listing their bad sectors. (They still come with a list, it's just now it is hidden in the firmware like you describe.)

I do some retro-computing every now and then and of these old drives that still work (about a 50% chance), when I format them assuming all sectors are good, they will inevitably report the same bad sectors as is on the label.

I don't really know why "bad sectors are still bad after 40 years" is so surprising to me, but there you go.

Re: Bubble Memory

#12

Post by bayindirh » Wed, Aug 05, 2026, 1:22 PM UTC

alnwlsn wrote: post #11

rwmj wrote: post #4

Earlier quoted context omitted.

Hard disks used to come with a paper label listing their bad sectors. (They still come with a list, it's just now it is hidden in the firmware like you describe.)

I do some retro-computing every now and then and of these old drives that still work (about a 50% chance), when I format them assuming all sectors are good, they will inevitably report the same bad sectors as is on the label. I don't really know why "bad sectors are still bad after 40 years" is so surprising to me, but there you go.

There's a step which "flashes" the magnetic structure on the disks during manufacturing which also allows drives to navigate the disk surface and "see" individual sectors. The bad sectors list from factory shows the points where this process has failed due to bad coating or other anomalies.

So they are not worn out sectors, they were bad (or not there) from the start. You can't rub them out, because there is not enough magnetic flux or material to store data at that address.

Re: Bubble Memory

#13

Post by cduzz » Wed, Aug 05, 2026, 1:28 PM UTC

iberator wrote: post #8

lxgr wrote: post #7

See also: https://en.wikipedia.org/wiki/Ferroelectric_RAM , which has been used in a few quite popular systems as well (e.g. the PS2 memory card supposedly uses it for some high-rewrite-count operations).

FRAM is also used in all modern MSP430 microntrollers from Texas Instruments. Amazing technology

That reminds me of core memory, which is also nonvolatile and for a long time was the primary memory of many computer systems.

I suspect "growing up" with a system where the computer itself is nonvolatile (turn it off, move it, turn it on, it's doing exactly what it was doing when it was turned off) changed the way people looked at computers vs modern systems.

It's too bad intel didn't push harder on their optane stuff. I guess it's too bad (for intel) for lots of different abandoned / failed projects.

Re: Bubble Memory

#14

Post by 4thguy » Wed, Aug 05, 2026, 1:34 PM UTC

I had initially learned about bubble memory from the Logopolis serial of Doctor Who. I actually went and looked it up after watching it because the concept sounded neat

https://tardis.fandom.com/wiki/Logopolis_(TV_story)

Re: Bubble Memory

#15

Post by GavinAnderegg » Wed, Aug 05, 2026, 1:39 PM UTC

I really enjoyed this 2025 video from The Retro Collective explaining this technology (with some rather fun arts-and-crafts examples) and showing off a Konami arcade board (sadly nonfunctional, but still cool to look at) that used it.

https://www.youtube.com/watch?v=DVJ9ED8mWt0

Re: Bubble Memory

#16

Post by intrasight » Wed, Aug 05, 2026, 2:16 PM UTC

We used Intel 7110 magnetic-bubble memory in our mobile robot. CMU early 80s. VMEbus I think it was.

Re: Bubble Memory

#17

Post by PaulHoule » Wed, Aug 05, 2026, 2:43 PM UTC

I remember a lot of talk about how transformative bubble memory was going to be circa 1980 and then quit hearing about it.

Re: Bubble Memory

#18

Post by alexpotato » Wed, Aug 05, 2026, 2:51 PM UTC

In Patriot Games by Tom Clancy, there is a scene early in the book where Jack Ryan is talking about the laptop he is using to write his book.

I don't remember the exact specs but am 100% sure he mentions that it has bubble memory.

Re: Bubble Memory

#19

Post by Dwedit » Wed, Aug 05, 2026, 2:58 PM UTC

lxgr wrote: post #7

See also: https://en.wikipedia.org/wiki/Ferroelectric_RAM , which has been used in a few quite popular systems as well (e.g. the PS2 memory card supposedly uses it for some high-rewrite-count operations).

MRAM (magnetic and non-volatile) had some applications in GBA cartridges to replace small amounts of battery-backed SRAM.

Re: Bubble Memory

#20

Post by jhallenworld » Wed, Aug 05, 2026, 3:19 PM UTC

I worked at a place that evaluated bubble memory, but didn't use it (they had the bubble memory dev. boards). But they did use CCD memory. I remember it was prone to bit errors, which would have been OK if there had been any error correction, but there was not.

https://deramp.com/downloads/mfe_archive/050-Component%20Spe...