# MySQL/Writing file error (Errcode 28)

If you have received an MySQL error with the error code and don’t know what the
code means, you can use the `perror` command to display the text explanation of
the error code.

```bash
perror 28

Output:
OS error code  28:  No space left on device
```

In this case, there is no free space on the device, therefore MySQL server
wasn’t able to write data on the disk.