Glossary term
What is SSD / HDD (Solid State Drive / Hard Disk Drive)?
SSD / HDD stands for Solid State Drive / Hard Disk Drive.
Permanent storage. SSD has no moving parts and is much faster. Example: Databases run far better on SSDs.
Learn it properly · System DesignLesson 10: Back-of-the-Envelope Estimation, Step by StepFive minutes of rough maths tells you whether you need one database or fifty. The numbers worth memorising, a seven-step recipe, and a full worked estimate for a photo-sharing app — with a calculator to try your own.