solid state drives
Solid-State Drives (SSD's)?
No
hard
SSD
SSD
Stepper motor
There is software that will overwrite data on the hard drive. Personally, I would dismantle the laptop, remove the drives, strip the drives and smash the platters. There is little value in selling old computers.
A spindle on a watch is a small cylindrical component that supports the hands of the watch. It acts as a pivot point for the hands to rotate around, allowing them to move smoothly and accurately to indicate the time. The spindle is connected to the movement of the watch, which drives the hands.
Most of the enclosure is made out of a metallic alloy however the main part of a hard drive, which stores the data magnetically, is called the platter. In a hard drive there are normally several platters. Platters can store data on both sides requiring a head (reader) for each side. The core of the platters are typically made using an aluminum or glass and ceramic substrate shaped into a disk. Then the disk is coated with a thin layer of a mostly nonmagnetic metallic alloy and on top of this is a protective carbon-based overcoat. Both of these layers are applied in the same process which is called sputtering. The next layer of the disk is a nanometer thin polymeric lubricant applied by dipping the disk into a solvent solution. The surface of the disk needs to be flawlessly smooth so that the disk head can rapidly move over the surface. Scott
Traditional magnetic hard drives use platters that spin and a magnetic head that applies negative and positive charges to the platters to record data in 1s and 0s. SSD drives are essentially flash drives similar to what is used in iPods. "Switches" in each memory "bank" are turned on and off with an electrical signal to record the data in 1s and 0s. SSD is faster because it does not have to "seek" for the location of the data on the hard drive.
Hard drives have movable parts as result their life time is limited be durability of metals and alloys which are used for the production. The ferromagnetic films on platters have limited lifetime too. And eventually start to decay.
Sort of. More importantly, steppers and spindle drives are both examples of synchonous AC motors with a magnetised rotor and AC-excited stator windings.