The disk electronics, also known as PCB (Printed Circuit Board), represent a crucial component of hard drives (HDD). It is responsible for controlling their operations and communicating with the computer system. The PCB contains a number of key components, including an MCU (Microcontroller Unit, serving as a processor), ROM (Read-Only Memory), RAM (Random-Access Memory, used as cache to speed up disk operations), disk motor controllers, power circuits, and in some cases, a NAND flash memory chip, especially in SSHDs (Solid-State Hybrid Drives). The PCB also includes an interface for connecting the disk to a computer.