OpenBSD, BSDI, and other Unix operating systems allow users to set chflags and fchflags on character and block devices.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Bsd_os | Bsdi | 3.2 (including) | 3.2 (including) |
| Freebsd | Freebsd | 3.2 (including) | 3.2 (including) |
| Openbsd | Openbsd | 2.5 (including) | 2.5 (including) |