The Decay Problem

Memory decay in computer memory cells is a growing concern for everyone. This refers to the gradual loss of data stored in a computer’s memory, due to a variety of factors, such as age, temperature, and the number of read-write cycles. This can lead to data loss, corruption, and other issues.

Too many R/W cycles will cause the memory to loss its ability to save new information, but, not using it at all will affect the information that already contains… why?… let’s see:

A memory cell in a computer can be thought of as a tiny capacitor that stores a charge to represent binary data (1 or 0). The charge (electrons trapped there) on the capacitor represents the binary state of the memory cell.

In a computer memory cell, the state of the charge on the capacitor represents the data stored in the cell. When a voltage is applied to one of the plates, it changes the charge on the capacitor, representing a change in the binary state of the cell.

To read the data stored in a memory cell, the voltage on the plates is measured. If the voltage is above a certain threshold, the cell is considered to be storing a 1; if the voltage is below the threshold, the cell is considered to be storing a 0.

Over time, the charge on the capacitor can leak away, leading to memory decay and the gradual loss of data stored in the cell.

Backups:

If you do a backup on a SD card and leave it for several years, there is a chance that the data stored on the card may experience some decay over time, depending on various factors such as temperature, humidity, and the number of read-write cycles done to the memory. However, reading the memory every few months can help to reduce this decay (with a small cost).

When you read the memory on the SD card, it activates the memory cells and applies a voltage to them, which can recharge the capacitors and help to maintain the data stored in the cells. This is because reading the memory refreshes the charge on the capacitors and helps to prevent the charge from leaking away over time.

It’s important to note that this mechanism is not foolproof, and the data stored on the SD card may still experience some decay over time, even with regular reading. However, regularly reading the memory can help to minimize the risk of decay and extend the lifespan of the data stored on the card.

How to read/refresh the whole memory:

Suppose that you don´t need to read this memory so often because this memory is just for keeping your old documents… but you still want to preserve them for different purposes (e.g. backups).

You only need to do this:

pv /dev/sdx > /dev/null

changing /dev/sdX by your device, you can explore what device you want to refresh using the lsblk command