Filters removed from drive housing.
Stator D.C. motor assembly.
Using the icons above the drive can be seen in various stages of disassembly. Two circuit boards mounted one on top of the other make up the complete controller. The two controller boards can be seen. These are almost entirely made with discrete logic ICs. This was common in the past but is never seen today.
The top board is hinged so that it can be moved without disconnecting. Disk drive controllers are basically computers which are dedicated to controlling and monitoring the drive.
Icon 4 shows the inside of the drive itself. The drive has been removed from the caddy and the controller boards have been removed. A lid from the top of the drive has also been removed. This part of the drive is normally sealed from dust and the air inside is filtered.
A 'voice coil' motor is used to move the heads over the disk surfaces. 'Mouseover' icon 5 to see the drive with the motor and head assembly removed.
Voice coil motors are used because of their fast and accurate movement. They work in the same manner as a coil in a loud speaker does to produce sound.
The top image on the right is of the head assembly removed from the drive. The heads glide just above the surface of the disks when they are spinning and can magnatise (write) or read the magnetic surface coating on the disk. Disks like these which appear brown use oxides of iron as the magnetic media.
It is worth mentioning that '1' and '0' are not written to the disk surface. Only momentary transitions can be written and read on the magnetic surface. These have to be converted to represent the digital data.
Filters, shown in the middle right picture, are used in drives to remove any small particles that could travel between a disk and the head. The small filter protects the drive from external air. The large filter cleans air cycled within the drive removing any particulate from the disks or components themselves. These filters should last for the life of the drive and are not intended to be replaced.
The stator coils and poles are shown in the lower right picture with the disk hub and magnets removed.