What does a bcache in Linux do?

What does a bcache in Linux do?

• "B" stands for binary coding, the bcache is an prior chaching method.
• Bcache is a advanced technology to encrypt your cache as an addition to full disc encryption.
• Bcache has nothing to do with Linux.
• Allows faster storage devices to act as caching devices for slower storage devices. 

EXPLANATION

Bcache allows one to use an SSD as a read/write cache (in writeback mode) or read cache (writethrough or writearound) for another blockdevice (generally a rotating HDD or array). For an intro to bcache itself, see the bcache homepage.