Hello everyone! Welcome to another one of my blogs.

This time, it will be about persistent storage technologies.

First one is magnetic storage of course. This includes tape, floppy disks, and our modern hard drives. It works by magnetising a platter using a writing/reading head(which is located inside hard drives or inside of the floppy drive bays), and that magnetises or reads the magnetisation of the target.
There are a few disadvantages, including lower speed, and moving parts, making it susceptible to vibrations, drops, etc. The motor rotating the disk will also eventually die, and because replacing the motor without adding any dust to the platter(effectively destroying the hard drive) is near impossible, its preety damn hard to recover the data.

Second one, we have optical storage
Optical storage works using a laser as the reading(and writing) head burning into the drive. These include CD-roms, DVD's, LaserDisks and similiar. The disadvantage of these is the very limited amount of write cycles, sometimes being only one(in case of DVD-R drives or similiar). It however has a outstanding amount of read cycles, being preety much near infinite, as long as you dont damage the drive physically. Some people at Microsoft are apparently working on an apparently glass based optical storage, that could last thousands of years and holding terabytes of data, but we have to wait for that couple of years to complete :)

Final one, solid state storage
As the name implies, this type of storage does not contain any moving parts. This includes sdcards, sata/nvme ssd's, usb thumb drives, and more. It works by having free electrons in a nand chip, where full of electrons representing 1(or 0 sometimes), and vice versa. The main advantage is speed, which can be up to multiple gigabytes every second these days.
The problem is partly in its persistency, and in its write cycles compared to magnetic storage. Every bit in solid state storage has couple of thousand write cycles, after which the drive turns into read-only mode, and after which it dies. You also need to periodically refresh the electrons, because after about 50years of the storage not being on, the data will start disapearing. SSD's are also expensivier than magnetic storage, however the gap between prices is shrinking, and some day it will propably be 0.
These disantages are not critical for almost all jobs, which is why they are almost everywhere, including servers, phones, personal computers, embeded devices, etc.

This is it for today, see you next time!