MRAM seems set to be the next big thing for the spintronics industry. But what can we say about the fallen heroes of magnetic storage from the past?
In this Pick of The Past we use the Google Ngram viewer to chart the rise and fall of different magnetic memory technologies over the last 60 years.
Before semi-conductor memory become as dominant as it is today, the computer industry relied on a range of different magnetic technologies for memory.
Magnetism offered relatively fast, cheap and non-volatile memory when the semi-conductor industry was just getting off the ground.
I’ve used the Google Ngram Viewer to see how the trends of different magnetic memory technology changed over time. I’ve picked out drum memory, twistor memory, bubble memory and MRAM which hopefully covers pretty much all of the key magnetic memory technologies.
Looking at the plot we can see which memories were most important at different times.
Drum memory was an early success, but was clearly later surpassed by magnetic core memory, which was where things really took off. Core memory dominated the computer memory market for about 20 years, and was the memory used for the computers in the Apollo moon missions. Twistor memory was essentially a variant of core memory, and seems to have made very little impact.
If we’re going to look at memory technologies we really do need to see how they compare to the later semi-conductor memories.
As core memory faded it was SRAM and DRAM that took its place. There was a valiant attempt from bubble memory to keep the magnetic memory dream alive, but this clearly came to very little in the early to mid 80s. Interestingly, or perhaps alarmingly, there has been a flattening or falling of the conventional DRAM and SRAM memories. Perhaps this fall from grace will help the rise of MRAM, or another magnetic memory technology.
And Then Came The Hard Drive
In memory, as opposed to storage, it is clear that semi-conductors won the battle against magnets as they rose to greatness in the 1980s. In terms of long-term storage of data, however, the magnet is still king.
The hard disk drive was introduced in the late 1950s and grew to become almost synonymous with computer storage itself. This final Ngram shows just how big an impact the hard drive has had in the last few decades.
Over the years the hard drive has relied on a number of spintronic phenomena to function, such as AMR and GMR. Like DRAM, however, the reign of the hard drive may have reached its zenith. What technology, magnetic or semi-conductor, could be just around the corner to replace it?