Ftp-WG: draft-somers-ftp-mfxx-01

> 1) Dave, what MUST servers do when asked to set a modification date which
> is earlier than the creation date?
>
> Reply with an Error Code and do nothing?
> Automatically set the Creation date equal to the new Modification date?

How about crash and burn? - just kidding!

I'm not sure whether attempting to set the modification date prior to the
creation date is an error. Sure, it may be silly (or just plain stupid), but
some filing systems allow this condition to happen (I think Windows NTFS
allows it).

How about this:

If MFF is not supported, the client-PI SHOULD issue MFCT (if supported)
before MFMT. This is to avoid the possible situation where the client-PI
could set the modification date to a date before the existing creation date,
which MAY be prohibited by the NVFS. However, it MAY be possible for a
client to attempt to set the modification time prior to the creation time;
this situation may be nonsensical, it may happen, and it is RECOMMENDED that
it not be considered an error by the server-PI.***

*** My feeling is that this is only an issue for Windows users where the
file system has the concept of create and modify facts. Unix/Posix systems
only have modify, so the create fact will never be able to be modified
because MFCT will not be implemented, and MFF will not support the Create
fact. I could be wrong. Comments/Corrections welcome!

> 2) Is a change to the Creation date a Modification?  Right now there is
> vagueness as to what changes constitute "Modification" and so call for
> changes of Modification dates.  Would it be appropriate to give guidance
> on what changes SHOULD call for changes to the Modification date, or is
> that to remain outside the scope of this work?

OK. I'm thinking of adding the following:

- All facts are to be considered autonomous, and modifying any facts MUST
not cause the server-PI to update the modify fact (unless impossible to
avoid due to the operating environment). The modify fact MUST only be
modified by either MFMT or through the Modify fact to MFF.

- Given the choice, client-PIs SHOULD use MFF in preference to issuing MFCT
then MFMT.

Cheers,

David