BSD enforces append-only when running proper securelevel. AFAIK, Linux lacks this attribute, and root can disable the so-called "immutable" attrib.
bsd enforces append only or immutable when the flag is set, not depending on the securelevel. there are "user" and "system" flag sets. the "user" flag set can be turned off and on at any time by either the file's owner or root. the "system" flag set can be set at any time, but can only be removed when the securelevel is less than or equal to zero, and can only be set or cleared by root. -- |-----< "CODE WARRIOR" >-----| codewarrior@daemon.org * "ah! i see you have the internet twofsonet@graffiti.com (Andrew Brown) that goes *ping*!" andrew@crossbar.com * "information is power -- share the wealth."