Cache: temporary speed boost, not permanent storage

A cache holds copies of frequently used data—like web pages, images, or app files—so your system can load them faster next time. The key contrast is with permanent storage: a cache is volatile or easily cleared, whereas a backup or database is meant to persist. For example, your browser caches a website's logo so it doesn't download it again on every visit, but clearing that cache won't delete the site's actual files—just the local copy.

In exams, watch for questions that treat cache as a reliable archive. A quick elimination trick: if an option says 'cache ensures data is saved forever' or 'cache replaces the need for backups,' it's wrong. Another hint: clearing cache often logs you out of sites because session tokens are stored there temporarily. So if a scenario mentions a user seeing an old page, the fix is to clear cache—but warn them they'll need to log in again.

To remember: think of a cache as a 'shortcut folder' that speeds things up but can vanish without warning. Test yourself by asking: 'If I delete this cache, do I lose the original data?' The answer is no—only the fast copy is gone. This helps you spot traps where cache is mistaken for permanent storage.