How does hardware store information?

Memory] The high or low of the circuit level indicates 0 and 1, and the power supply is needed, and the state is lost when the power is off;

Hard disk] uses the polarity of the magnetic material in a very small area to represent 0 and 1, because the magnetic material can keep the direction of the magnetic field unchanged, so it can be saved in a power-off state, unless the external magnetic field is affected;

Disc] is engraved with a laser to change the reflective characteristics of a very small area, and the usual one cannot be erased (written at one time), such as the blue laser called the blue disc;

Flash] is used to save the state with a tiny FET, which can be maintained even after power failure, and is used in U flash drives and other equipment.

There are a lot of contents involved in the latter questions, please check them separately. Roughly speaking, they are all electronic logic devices, and there are time tubes-transistors-large-scale integrated circuits, and the volume and power consumption are also changed from large to small in this order.

This suggests that you take a look at the book about storage, not a sentence or two can be made clear, the most basic storage is indeed binary, through a switch state to save the binary state, and then form a storage unit. The relationship between electron tubes, transistors, and LSI is just a basic computer book, and the first chapter is about these.

The following questions are good, but the relationship between the latter three is not very big. What do you do?

Principle: Dynamic memory is mainly used in computers, and dynamic memory has only one input data line per chip, and only 8 address pins. In order to form a 64k address, an address formation circuit must be designed between the system address bus and the chip address lead, so that the system address bus signal can be added to the pins of the 8 addresses in a cluster.

With the help of the row latch, column latch, and decoding circuits inside the chip, the memory cells in the chip are selected, and the latching signal is also generated by the external address circuitry.

When it comes to reading data from the DRAM chip, the CPU first adds the line address to the sidepads A0-A7 and then sends out a RAS latch signal, which locks the address inside the chip by the falling edge of the signal. Then add the column address to the A0-A7 of the chip, and then send the CAS lock.

1. The unit in SRAM is a number of switches to form a trigger, which can stably store 0, 1 signals, and at the same time can change the stored values through timing and input signals.

2. DRAM, mainly according to the amount of electricity on the capacitor, when the power is large, the voltage is high to indicate 1, and vice versa means 0

The chip is made up of a lot of these cells, so it can store data.

A program is data. The circuit reads data from the memory chip, and the data of other memory cells can be modified according to the timing of the circuit and the logic operation of the circuit.

Data storage is the temporary file generated by the data flow during the machining process or the information that needs to be found during the machining process. The data is recorded in some format on a computer's internal or external storage media. The data store should be named, and this naming should reflect the composition and meaning of the information features.

The data flow reflects the data flowing in the system and exhibits the characteristics of dynamic data. Data storage reflects the data at rest in the system and exhibits the characteristics of static data.

Take hard disk storage as an example to introduce the principle:

A hard disk is a data storage device that uses magnetic media to store data on several disk plates sealed in a clean cavity of the hard disk drive. These discs are generally formed by coating the surface of the substrate with magnetic medium, and on each side of the disk, a number of concentric circles with a rotating shaft as the axis and a certain magnetic density as the interval are divided into tracks, and each track is divided into a number of sectors, and the data is stored on the hard disk according to the sectors. There is a corresponding read/write head on each face, so all the tracks in the same position of different heads form the so-called cylinder.

Traditional hard disk reads and writes are addressed by cylindrical, head, and sector (CHS addressing). The hard disk rotates at high speed after power-on, and the head located on the head arm is suspended on the surface of the disk, and can be moved between different cylinders through a stepper motor to read and write different cylinders. Therefore, if the hard disk is subjected to violent oscillation during power-on, the surface of the disk is easily scratched, and the head is also easily damaged, which will bring catastrophic consequences to the data stored on the disk.

I didn't expect the principle of database storage data to be understood in this way, it's too simple!

Copied over, hehe.

How modern hard drives work.

Today's hard drives, whether IDE or SCSI, are used"Winchester's technology has the following characteristics:1. Magnetic head, disc and kinematic mechanism sealed.

2。The surface of the plated disc plate, which is fixed and rotated at high speed, is flat and smooth. 3。

The head moves radially along the platter. 4。The magnetic head starts and stops in contact with the platter, but it is in flight and does not have direct contact with the platter when working.

Platter: A hard disk platter is a magnetic particle attached to the surface of an aluminum alloy (glass is also used for new materials). These magnetic particles are divided into concentric circles called tracks, and on the tracks of each concentric circle there are as if there are countless small magnets of any arrangement, which represent states of 0 and 1, respectively.

When these small magnets are subjected to a magnetic force from the head, the direction of their alignment changes. The magnetic force of the head is used to control the direction of a number of small magnets so that each small magnet can be used to store information.

Disk: The disk body of a hard disk is composed of multiple platters, which are stacked together in a sealed box, and they are driven by the spindle motor to rotate at a very high speed, and its speed per minute reaches 3600, 4500, 5400, 7200 or even more.

Head: The head of the hard disk is used to read or modify the state of the magnetic material on the platter, generally speaking, each magnetic surface will have a head, starting from the top, numbered from 0. When the head stops working, it is in contact with the disk, but it is in flight when it is working.

The head takes the contact start and stop method in the landing area of the platter, and the landing area does not store any data, and the head starts and stops in this area, and there is no problem of damaging any data. When the data is read, the platter rotates at high speed, and the head is in a "flying state" at a micron height from the data area of the disc due to the ingenious aerodynamic design for the head movement. It does not cause wear and tear in contact with the disc surface, and the data can be read reliably.

Motor: The motors in the hard disk are all brushless motors, which have little mechanical wear and tear under the support of high-speed bearings, and can work continuously for a long time. The high-speed rotation of the disc body produces an obvious gyroscopic effect, so the working hard disk should not be moved, otherwise it will increase the working load of the bearing.

The seek feeding motor of the hard disk head mostly adopts voice coil rotation or linear motion stepper motor, which accurately tracks the track of the platter under the adjustment of feeding clothing tracking, so there should be no impact collision when the hard disk is working, and it should be handled carefully when moving.

Image analysis of how a computer hard drive works.