We have shown that digital logic can be used to create outputs based on detected physical states of matter. It also can be used directly to alter the environment. An AND circuit with two inputs TURN ON THE HEAT and TEMPERATURE BELOW 40 DEGREES could provide electrical current to heat an area that is below 40 degrees and then turn itself off.
But to perform any complex analysis of data requires the ability to store and retrieve historical data values. There are many classes of storage devices, some of which, do not require a biological agent to exist.
ECHO
We usually think of echoes as reflections of sound from solid objects. Or as Wikipedia incongruously puts it “Acoustic waves are reflected by walls or other hard surfaces, such as mountains and privacy fences. ” Light waves can also produce echoes. Laser waves because of their intense beam can send data images to the moon.
When I first worked for IBM in 1963, memory storage was very expensive and had a slow response time. One of the products I supported in the Pentagon was the 2260 terminal. It used a piece of wire stored inside a small oven (to keep the length of the wire constant) as its screen memory.
From the IBM 2260 – Wikipedia article
The 2848 stored the digital image of screens of information in an acoustic delay line. Before the introduction of integrated circuit chips, the technology was based on discrete-component individual transistors. Mainframe computers used magnetic core memory, which was too expensive for use in video display terminals. The delay line was an unusual mechanical (not electrical) spiral wire with an electromagnet on one end and a torsion rotation detector on the other (which was conceptually similar to a phonograph needle pickup). The central controller system vibrated the electromagnet like an audio-speaker voice coil. A fraction of a second later, the other end of the mechanical wire would vibrate. The vibration was converted to raster scan lines and sent to the nearby CRT display. The IBM 2848 delay line was a continuous electromechanical feedback loop.
More generally, Delay-line memory – Wikipedia, could store a string of data and feed the output back into the input. The first practical use was in WWII radar in England. Stationary objects, such as buildings and parked planes would produce echoes that clutter the screen. Echoes from these objects would be fed into the end of a tube of mercury exactly long enough for one radar scan. The output would be retrieved and inverted to remove their signal, making the detection of incoming planes easier.
Digital Memory
Digital circuits can be easily joined to create a storage cell for data. Flip-flop (electronics) – Wikipedia. An input pulse would store the data until a reset signal is sent. The NOR gate used is an OR gate with an INVERTER gate attached to the output.
Other digital storage devices include Bubble memory – Wikipedia and Programmable ROM – Wikipedia. Both of these use a “captured” electrical charge to store data.
Magnetic Memory
When I first starting working, Magnetic-core memory – Wikipedia was the medium used in mainframe computers and magnetic tape drives 9-track tape – Wikipedia.
Solid State
Of course, today almost all data is stored on a solid state device Solid-state drive – Wikipedia.
Next Chapter Communication
