Storage is a crucial component of a PC, responsible for storing data and the operating system. It primarily includes mechanical hard drives (HDDs) and solid-state drives (SSDs).

(1) Mechanical Hard Drive (HDD – Hard Disk Drive)

① Structure

HDDs consist of the following components:

• Platters: Rotating disks coated with a magnetic material where data is stored.
• Read/Write Heads: Components that read and write data on the platters.
• Spindle Motor: Rotates the platters at high speeds (typically 5400 RPM or 7200 RPM).
• Actuator Arm: Moves the read/write heads to different locations on the platters.
• Controller Board: Manages data access and controls motor functions.

② Working Principle

• The platters spin at high speeds while the read/write heads move across them to locate and access data.
• Data is stored and retrieved as magnetic signals.

③ Classification

④ Classification Reasons

Higher RPM results in faster data access, but also increases power consumption and noise.

(2) Solid-State Drive (SSD – Solid State Drive)

① Structure

• NAND Flash Memory: Stores data electronically instead of magnetically.
• Controller Chip: Manages read/write operations, error correction (ECC), and garbage collection (GC).
• DRAM Cache (on some SSDs): Improves speed and reduces latency.

② Working Principle

SSDs use electronic signals to read and write data, eliminating mechanical parts. This results in much faster speeds and higher durability.

③ Classification

④ Classification Reasons

• Interface determines speed: SATA is limited to 600MB/s, whereas PCIe 5.0 can reach 14,000MB/s.
• NAND technology affects lifespan and performance (SLC > MLC > TLC > QLC).