Wirebook › Glossary › Fake-capacity drive
What is a fake-capacity USB stick or SD card (and how do you catch one)?
In one sentence: A USB stick or memory card whose controller has been set to report far more space than it really has, so files past the real size are lost or overwrite older ones.
A little more
Every USB stick and memory card has a tiny controller chip that tells the computer how big it is. On a fake, that number has been edited, so a 32 GB chip can claim to be 1 TB or more. The computer believes it, formats the full size and copies files without any error.
Once the real memory is full, the controller either throws new data away or loops back and writes over the start of the drive. Nothing complains at the time; the damage only shows when you open the files later. The only reliable check is to fill the whole drive with numbered test data and read every bit back, which is what H2testw, f3 and ValiDrive do. The amount that comes back correct is the real size.
See it in action
- BonusWhy is copying to a USB stick so slow?Send ants carrying crumbs from a laptop, over a bridge, into a USB stick and watch what really slows a copy down: a skinny USB 2 bridge, tired ants when the fast cache runs out, or paperwork for thousands of tiny files.10 min · interactive
- 8Where do deleted files and photos go?Delete a photo, empty the bin, and watch what really happens on a pretend disk: the file is forgotten, not rubbed out.7 min · interactive
Do it for real
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