Software → Operating Systems
Disk I/O
Reading from or writing to persistent storage devices such as SSDs or hard disks.
Motivation
Disk I/O solves the problem of reading and writing persistent data, but it is usually much slower than memory access.
Where it fits
Disk I/O belongs to operating systems, storage, databases, and performance engineering.
Mental model
Disk I/O is communication with persistent storage; performance depends heavily on access patterns, buffering, and batching.
Common mistakes
- Treating disk access like memory access.
- Ignoring sequential vs random access patterns.
Related concepts
Disk I/O connects to file system, database, write-ahead log, B-Tree, LSM-Tree, and latency.