Memory bank still holds an attractive idea: A look at magnetic core memory - MRAM - manufacture which still has the potential to cut boot up and shut down times for PCs

摘要

One of the more challenging problems in the history of the development of computer technology is the storage and retrieval of information. Early solutions included the use of punched cards, or encoding onto magnetic tape or drums. In the latter case the information was usually put into the form of either of two states, a zero or a one, alternatively, a yes or a no: a binary statement. A secondary problem was the location of the data because it was stored sequentially in the early memory systems and it could not be accessed randomly. Early solutions to memory access were flip-flop circuits that used thermionic tubes and, later, transistors which were costly per bit of information. For this reason attention turned to the phenomenon of the rectangular hysteresis loop characteristic of ferrite toroids, also known as cores. See Figure 1. An important feature of core memory is that it is non-volatile and will not lose its contents when power is removed.