[tahoe-dev] [tahoe-lafs] #628: "mtime" and "ctime": I don't think that word means what you think it means.

tahoe-lafs trac at allmydata.org
Mon Feb 16 20:28:36 UTC 2009


#628: "mtime" and "ctime": I don't think that word means what you think it means.
---------------------------+------------------------------------------------
 Reporter:  zooko          |           Owner:           
     Type:  defect         |          Status:  new      
 Priority:  major          |       Milestone:  undecided
Component:  code-dirnodes  |         Version:  1.2.0    
 Keywords:                 |   Launchpad_bug:           
---------------------------+------------------------------------------------
 Tahoe has "mtime" and "ctime" associated with the edges in the filesystem
 graph (the entries in a directory).  Tahoe means by "mtime" the most
 recent time that the link was changed to point to a new node than it
 previously pointed to ("modify time"), and by "ctime" the most recent time
 that the link was created when there was previously no link under that
 name ("create time").  The traditional unix values "mtime" and "ctime"
 don't have these semantics.  In Unix, mtime is the most recent time that
 the file contents changed, and ctime is the most recent time that the
 inode changed, which means that ''either'' the file contents changed or
 else the metadata (such as owner or permission bits) changed.

 (It is a common mistake to think that "ctime" in unix means create time.)

 The tahoe semantics are certainly more useful for Tahoe than unix
 semantics would be (since we don't have owners or permission bits, and
 since "the most recent time this link was created when previously there
 was no link by that name" is potentially useful).  But if we're going to
 be deploying new semantics, let's deploy them under new names.  How about
 if we just spell it out: "create time" and "modify time".  That will also
 be understood by more people than abbreviations would.

-- 
Ticket URL: <http://allmydata.org/trac/tahoe/ticket/628>
tahoe-lafs <http://allmydata.org>
secure decentralized file storage grid


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