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Anyone else have an attraction to Magnetic Bubble Memory?

C

candrews

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Jan 29, 2016
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Location
WA State, USA
Ever since hearing about magnetic bubble memory, I have wanted to make a card for my 8085 single board computer system. However first it was limited release, then it was too expensive, then it was history. Finally, I am getting around to building a bubble memory card and just got it fired up and reading today. So I was wondering if there are any other magnetic bubble memory fans out there. Probably unlikely but if there are I wanted to share this project. After polishing up the documentation and possibly making another revision of the PCB, the build files will be released just as the rest of the SBC-85 system. In the meantime, I have the project and logs on Hackaday.IO video at YouTube

regards

craig
 
Sold my Intel SDK some time ago. BM always seemed like a solution in search of a problem. A bit power-hungry when operating, requiring flaw maps and quite a bit of silicon to work--and serial storage.
 
Konami famously used bubble memory for the Gradius and TwinBee arcade boards in the mid 80s. They are known for being terribly unreliable
 
They require a bias field and a rotation field to shift the bits( not actually rotating but a sine, cosine ). The shift works by the shape of the distortions on the surface that make like a one way transfer of the bubbles. Running the coils took really powerful FETs. Of course some of today's MOS FETs are much better than the one originally used in the driver chips Intel made.
Dwight
 
As far as reliability, bubble had excellent reliability if the design implementation was good. Some of the best were the Intel iSBC256 for multibus and their iSBX. They also had a bubble option in the iPDS. Fanuc, Allen Bradley, both had excellent bubble cards.
 
I thought the last manufacturer of bubble memory stopped producing that about 15 years ago. On the other hand, if the testing results were accurate, bubble memory units should be able to survive a lot of abuse.
 
I forget the part number, but there is an intel bubble kit that has the 7110 and its five support chips. (The 7220 controller is not included in the kit since it could control eight bubble chip sets). This board basically uses one of those kits and the 7220 controller. Occasionally I see these new old stock kits come up on eBay.
 
Great video, educative and easy to follow. Last year I dumped a bubble based game (Gradius) so it could be preserved in MAME, interesting project and technology.
 
Yes, I used the Intel BPK-72 Bubble Memory Prototype Kit (http://www.decadecounter.com/vta/articleview.php?item=359) many years ago.

I wire-wrapped my own MULTIBUS-1 card and developed the boot and save software for a 286/10A CPU card.

Up to this point we had been using TU-58 tape cartridges or 9k6 serial lines to boot and save the software. This was somewhat quicker shall we say!

It was never used in the end (neither was my iSBX586 ETHERNET card and device driver) - but they proved my case when discussing things in meetings with managers (I could actually demonstrate a working prototype)...

I still have the BPK-72 in its box in the loft somewhere I think. I think I repurposed the MULTIBUS-1 prototyping card though?

Dave
 
I don't believe anyone makes them any more. Bubble, like magnetic core and magnetic wire memory was not as effected by EMP as silicon memory. Once they understood what caused the alternators in Hawaii to fail when they exploded a nuclear bomb above the atmosphere, they realized they had a problem. The military soaked up all the bubble memory, including some that was second hand, because it was only manufactured for such a short time.
It took a lot of power to make the magnetic fields for the shifting. Most of the power was wasted as heat. This made them not practical for normal commercial applications, like boot memory, compared to cheaper and lower power EPROMs. CMOS memory with battery backup was cheaper for those boot parameters that had to be updated often.
Dwight
 
edcross said:
Great video, educative and easy to follow. Last year I dumped a bubble based game (Gradius) so it could be preserved in MAME, interesting project and technology.
Click to expand...

Thanks. I plan on doing one more video on bubble memory since the technology was so short lived it is unheard of by most of the young’ns.
 
Schematics and BOM for the SBC-85 Bubble Board are nowuploaded if you are interested

Schematics and BOM for the SBC-85 Bubble Board are nowuploaded if you are interested

The schematic, some driver utilities, and BOM for the 1Mbit bubble board are up on the project website now:
http://sbc-85.com/index.php/documentation/
 
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