Historical question, what went wrong with bubble memory?
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From: =?iso-8859-1?q?Torben_=C6gidius_Mogensen?= on 20 Oct 2006 05:11 Jan Vorbr?ggen <jvorbrueggen(a)not-mediasec.de> writes: >> Wasn't bubble memory used on the onboard computer in the space >> shuttle? > > Nope. The original design used core. When the processors were > upgraded, the memory was upgraded to semiconductor memory (and much > larger capacity) as well. As core is inherently radiation-tolerant and > transistors are not, the new memory design has ECC and runs a scrubber > task in the background. This introduces an operational change: With > core, some of the GPCs were "freeze-dried" on orbit, i.e., loaded with > software (e.g., for an emergency descent) and turned off. The new > design needs to keep them running, with only the scrubber task active. I googled a bit and found that bubble memory was used on the shuttle, but not in the onboard computers. Instead, they were used in the Grid laptop computers that were brought on several mission. That may have been what I was vaguely remembering. Torben
From: CBFalconer on 20 Oct 2006 08:47 Larry__Weiss wrote: > Peter Flass wrote: >> Christopher C. Stacy wrote: >> .... snip ... >>> >>> It was used for secondary storage on a version of the TI Silent >>> 700. I think the FTD (Florist) network was based on these. >> >> This rings a bell. You have a darn good memory. > > A little web surfing reveals that the bubble memory version was > the model 765. > > I don't think I ever used that model, but I sure remember using > up a lot of thermal paper on the older Silent 700! I moved a little over a year ago, and finally threw out a stack of black plastic wrapped TI thermal paper. -- Chuck F (cbfalconer at maineline dot net) Available for consulting/temporary embedded and systems. <http://cbfalconer.home.att.net>
From: krw on 20 Oct 2006 12:28 In article <1161187649.041990.65950(a)f16g2000cwb.googlegroups.com>, dereks314(a)gmail.com says... > > kenney(a)cix.compulink.co.uk wrote: > > I can remember several years when magnetic bubble memory was > > going to be the next big thing, replacing most other forms of > > storage. It then seemed to disappear without trace. Has > > development stopped? > > > > Ken Young (original post not on my server) The cost of floppy drives fell below the cost of bubble. In the early '80s I worked on the qualification of bubble controllers. After about six months the project was canceled because floppy drives would cost $35 (they were in the $200 range at the time). > If I remember right it was very slow, very expensive, not completely > reliable and I think IBM held most if not all the patents. Being slow > might have been related to reliably reading and writing to the device. Never heard of any data integrity issues. -- Keith
From: Joseph H Allen on 23 Oct 2006 10:12 I remember CCD memory in the same era (one company I worked for used a 256 KB CCD memory card for secondary storage in an MC6809 based computer)... it certainly did have data integrity issues. -- /* jhallen(a)world.std.com (192.74.137.5) */ /* Joseph H. Allen */ int a[1817];main(z,p,q,r){for(p=80;q+p-80;p-=2*a[p])for(z=9;z--;)q=3&(r=time(0) +r*57)/7,q=q?q-1?q-2?1-p%79?-1:0:p%79-77?1:0:p<1659?79:0:p>158?-79:0,q?!a[p+q*2 ]?a[p+=a[p+=q]=q]=q:0:0;for(;q++-1817;)printf(q%79?"%c":"%c\n"," #"[!a[q-1]]);}
From: Jeff Jonas on 11 Nov 2006 20:20
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 >I also have a vague recollection, which I have not been able to >verify by poking about the web, of there being scaling limits to the >technology such that they couldn't get much beyond 1e6 bits/cm^2 NASA Tech Briefs had a followup article several years later about a 3D version of bubble memory that would've scaled up better, but nobody tooled up to make it. -- -- mejeep deMeep ferret! |