Data has been stored in many different ways over the years as storage media have become smaller, faster, and better. In a recent article for ACM Queue, Jessie Frazelle takes readers on a comprehensive tour of the various data storage methods used throughout computing history.
For example, in the time of Babbage's Analytical Engine, “a bit was stored as the position of a mechanical gear or lever. In the case of paper cards, a bit was stored as the presence or absence of a hole in the card at a specific place. For magnetic storage devices, such as tapes and disks, a bit is represented by the polarity of a certain area of the magnetic film,” Frazelle says.
In modern dynamic random-access memory (DRAM), she says, “a bit is often represented as two levels of electrical charge stored in a capacitor, a device that stores electrical energy in an electric field.”
As Frazelle details in this informative and entertaining article, “storage has changed a lot over time—from paper tape to metal tape, magnetic tape, rope memory, spinning disks, optical disks, flash, and others.” What remains true, she notes, is the storing of 0s and 1s, while the methods by which that is done vary greatly.
Read the complete article at ACM Queue.