[TUHS] When/how did ctime change from inode "creation" to "change" time?

[Rob Pike]

Or perhaps the comment was wrong?

I do remember being confused by it.

-rob


On Wed, Mar 12, 2025 at 1:19 PM Theodore Ts'o <tytso at mit.edu> wrote:

> As part of a discusion on the Linux kernel mailing list, there was an
> assertion that ctime was orginally "creation time".
>
> From the v7 sources in TUHS, we can see:
>
> struct dinode
> {
>         unsigned short  di_mode;        /* mode and type of file */
>         short   di_nlink;       /* number of links to file */
>         short   di_uid;         /* owner's user id */
>         short   di_gid;         /* owner's group id */
>         off_t   di_size;        /* number of bytes in file */
>         char    di_addr[40];    /* disk block addresses */
>         time_t  di_atime;       /* time last accessed */
>         time_t  di_mtime;       /* time last modified */
>         time_t  di_ctime;       /* time created */
> };
>
> ... although the v7 kernel sources does seem to update ctime when the
> inode metadata changes, regardless of what the coment in
> /usr/src/sys/h/ino.h might say.
>
> More interestingly, this comment seems to continue in newer versions
> up to 3BSD, and then the comments becomes "change time" in BSD 4.2,
> probably coincident with the File System Implementation?
>
> The best we can guess is that the change from "creation time" to
> "inode change time" happened sometime between 1979 and 1982.  Does
> anyone who was around can give the story about how and when this
> happened?
>
>                                         - Ted
>
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