Bubble memory is a type of non-risky laptop memory that uses a skinny movie of a magnetic material to carry small magnetized areas, referred to as bubbles or domains, each storing one bit of information. The fabric is organized to form a series of parallel tracks that the bubbles can move alongside underneath the action of an external magnetic field. The bubbles are read by moving them to the edge of the material, the place they can be read by a standard magnetic pickup, and then rewritten on the far edge to maintain the memory cycling by the fabric. In operation, bubble memories are just like delay-line memory programs. Bubble memory began out as a promising expertise within the 1970s, offering performance just like core memory, memory density much like laborious drives, MemoryWave and no moving parts. This led many to consider it a contender for a "universal memory" that could possibly be used for all storage wants.

The introduction of dramatically faster semiconductor memory chips in the early 1970s pushed bubble into the sluggish end of the scale and it started to be thought of mostly as a substitute for disks. The equally dramatic enhancements in exhausting-drive capacity through the early 1980s made it uncompetitive in price phrases for mass storage. Bubble memory was used for a while within the 1970s and 1980s in functions where its non-transferring nature was desirable for maintenance or shock-proofing causes. Bubble memory is basically the brainchild of a single individual, Andrew Bobeck. Bobeck had labored on many sorts of magnetics-associated projects by means of the 1960s, and two of his projects put him in a very good position for the event of bubble memory. The first was the event of the primary magnetic-core memory system driven by a transistor-primarily based controller, and the second was the event of twistor memory. Twistor is essentially a model of core memory that replaces the "cores" with a bit of magnetic tape.

The main benefit of twistor is its potential to be assembled by automated machines, as opposed to core, which was almost fully handbook. AT&T had great hopes for twistor, believing that it could drastically cut back the price of computer memory and put them in an trade main position. As an alternative, DRAM recollections got here onto the market in the early 1970s and rapidly changed all previous random-entry memory systems. Twistor ended up getting used only in a number of applications, lots of them AT&T's personal computer systems. One interesting side impact of the twistor idea was observed in production: below certain circumstances, passing a present by way of one of the electrical wires running contained in the tape would cause the magnetic fields on the tape to move within the course of the present. If used properly, it allowed the stored bits to be pushed down the tape and pop off the tip, forming a type of delay-line memory, but one where the propagation of the fields was under computer control, versus automatically advancing at a set fee outlined by the supplies used.

Nevertheless, such a system had few advantages over twistor, especially because it did not allow random entry. In 1967, Bobeck joined a crew at Bell Labs and started work on enhancing twistor. The memory density of twistor was a function of the dimensions of the wires