Historical question, what went wrong with bubble memory?
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From: krw on 12 Nov 2006 19:54 In article <ej5ss5$fdu$1(a)panix5.panix.com>, jeffj(a)panix.com says... > I think FLASH, EEPROM and other non-volatile memories > were the death of bubble memory, > particulary when they became 5v only. The price crash on the floppy disk was the death knell for bubbles. Without that mass market they couldn't slide down the technology curve. -- Keith
From: Charles Richmond on 13 Nov 2006 13:03 Jeff Jonas wrote: > > I think FLASH, EEPROM and other non-volatile memories > were the death of bubble memory, > particulary when they became 5v only. > > >> Anyway, one problem I recall with BM was that the bubbles were > >> arranged on rings, there was one primary ring hooked to multiple > >> secondary rings. A bubble was rotated from a secondary ring to the > >> primary ring, and then moved under the read "head" (this is all from > >> memory...), which did a destructive read, and wrote it back. You > >> had to be careful to rotate the rings to a known position before > >> power off, so the memory was non-volatile, but you could scramble it > >> easily enough. > > >Oh yeah, that sounds right. You just tweaked a neuron. > >I remember thinking that you will need to devote one secondary ring > >to storing a single bit to mark the origin position. Also some of the > >secondary rings were bad so you had to skip those positions on the > >primary loop when storing/retrieving. But I see from poking about > >the web that later Intel added an extra secondary 'boot loop' to > >store both the origin marker and good/bad map which their controller > >chip would load on start up. > > I have the developer's kit of bubble module, controller chip > but the databook's somewhere else ... > so I can't look up access times, failure modes, etc. > I'm inclined to agree that > - reading or writing was an uninterruptable process due to > shifting the bubbles around the ring > (or recoverable if the position was saved) > - it needed a fair amount of power for the electromagnets > ISTM that bubble memory was like a mercury delay line...just a bunch of parallel shift registers moving bits around. Access time depended on where in the loop that the desired bits resided. Also ISTM that this would *not* scale well. Bubble memory modules were large for the late 70's, but *not* so large compared to flash memory today. -- +----------------------------------------------------------------+ | Charles and Francis Richmond richmond at plano dot net | +----------------------------------------------------------------+
From: Charles Richmond on 13 Nov 2006 13:12 krw wrote: > > In article <ej5ss5$fdu$1(a)panix5.panix.com>, jeffj(a)panix.com says... > > I think FLASH, EEPROM and other non-volatile memories > > were the death of bubble memory, > > particulary when they became 5v only. > > The price crash on the floppy disk was the death knell for bubbles. > Without that mass market they couldn't slide down the technology > curve. > The Texas Instruments Silent 700 terminal was the only device that I was aware of...that contained a bubble memory module. It also had an acoustic coupler 300 baud modem built in, and used a thermal printing mechanism. -- +----------------------------------------------------------------+ | Charles and Francis Richmond richmond at plano dot net | +----------------------------------------------------------------+
From: Andrew Swallow on 13 Nov 2006 13:20 Charles Richmond wrote: > Jeff Jonas wrote: >> I think FLASH, EEPROM and other non-volatile memories >> were the death of bubble memory, >> particulary when they became 5v only. >> >>>> Anyway, one problem I recall with BM was that the bubbles were >>>> arranged on rings, there was one primary ring hooked to multiple >>>> secondary rings. A bubble was rotated from a secondary ring to the >>>> primary ring, and then moved under the read "head" (this is all from >>>> memory...), which did a destructive read, and wrote it back. You >>>> had to be careful to rotate the rings to a known position before >>>> power off, so the memory was non-volatile, but you could scramble it >>>> easily enough. >>> Oh yeah, that sounds right. You just tweaked a neuron. >>> I remember thinking that you will need to devote one secondary ring >>> to storing a single bit to mark the origin position. Also some of the >>> secondary rings were bad so you had to skip those positions on the >>> primary loop when storing/retrieving. But I see from poking about >>> the web that later Intel added an extra secondary 'boot loop' to >>> store both the origin marker and good/bad map which their controller >>> chip would load on start up. >> I have the developer's kit of bubble module, controller chip >> but the databook's somewhere else ... >> so I can't look up access times, failure modes, etc. >> I'm inclined to agree that >> - reading or writing was an uninterruptable process due to >> shifting the bubbles around the ring >> (or recoverable if the position was saved) >> - it needed a fair amount of power for the electromagnets >> > ISTM that bubble memory was like a mercury delay line...just > a bunch of parallel shift registers moving bits around. Access > time depended on where in the loop that the desired bits resided. > Also ISTM that this would *not* scale well. Bubble memory modules > were large for the late 70's, but *not* so large compared to > flash memory today. Bubble memory's slowness meant it was never really an alternative to ram and rom but magnetic disks. Its small storage capacity meant that it could not take on hard/fixed disks and since it was not exchangeable it could not take on floppy disks. With hindsight bubble memory needed to interface by a USB port. Pity they were 30 years away. Andrew Swallow
From: russell kym horsell on 13 Nov 2006 19:42
In comp.arch Charles Richmond <richchas(a)comcast.net> wrote: .... > ISTM that bubble memory was like a mercury delay line...just > a bunch of parallel shift registers moving bits around. Access > time depended on where in the loop that the desired bits resided. > Also ISTM that this would *not* scale well. Bubble memory modules > were large for the late 70's, but *not* so large compared to It was the horseshoe magnet that took up all the space. > flash memory today. |