Bubble memory markings

From: Dwight Elvey <elvey_at_hal.com>
Date: Fri Jun 4 15:02:11 1999

Dwight Elvey <elvey_at_hal.com> wrote:
> Doug Spence <ds_spenc_at_alcor.concordia.ca> wrote:
> > Hi,
> >
> > Does anyone know what all the numbers on the backs of Intel Magnetics
> > bubble memory modules mean?
> >
> > One of the three modules that I have has a penciled-in line separating
> > every 4th digit, so it looks like maybe some kind of address, but I
> > think the modules each store 128KB and 16 bits wouldn't be enough.
> >

Hi
 I think we should clarify for Doug how you access Bubbles.
These are not like standard read/write memory. You have to treat
them more like a disk drive. The memory is organized into
a number of loops. You can only see one location on each loop
at any one time. This means that they are serial devices.
To access all of the bits on the loop, you have to clock
the chip with external magnetic fields to cause the bubble
bits to rotate around the rings. Think of it as being
something like a loop of paper tape in a tape reader.
You can read anything but only one location at a time.
 To run the coils takes quite a bit of energy. Making
the multi-phase clocks with drivers is tricky even
by todays standards. Originally, Intel made some VMOS
driver chips that were used with these bubble memories.
 This is partly why Intel gave them up. They still had
a lot on Mil applications because they are considered
to be non-volatile like core. Too much power and they
could see the end of density increases.
Dwight
Received on Fri Jun 04 1999 - 15:02:11 BST