zeleznik%cs.utah.edu@wasatch.utah.edu (Mike Zeleznik) (08/24/89)
Is there a good reason why wbak uses the mod time of a file instead of its
create time for incrementals?
The problem is if you "cp -p" in from another machine, or tar stuff in, the
mod times will stay as the original (which is usually what one wants, along
with keeping the modes). But now, in general, these "new" files won't get
backed up til the next full save (unless the mod times happened to be
in the right window). I don't think this would happen with ctime.
This seems kind of a big hole for people who move things around.
I understand OmniBack uses mod times also (correct me if I am wrong).
Is there a reason for not using ctime? Thanks.
Mike
Michael Zeleznik Computer Science Dept.
University of Utah
zeleznik@cs.utah.edu Salt Lake City, UT 84112
(801) 581-5617zeleznik%cs.utah.edu@wasatch.utah.edu (Mike Zeleznik) (08/24/89)
In article <3188@wasatch.utah.edu> zeleznik%cs.utah.edu@wasatch.utah.edu (Mike Zeleznik) writes: >Is there a good reason why wbak uses the mod time of a file instead of its >create time for incrementals? > Please note: I realize mod time is the logical choice by its name. Create time just seemed to catch more common changes in the files than mod time. From what I have seen, both create and mod time are reset on append and on edit, but create time will also catch the previously mentioned common situations that mod time misses. However, as was pointed out, there are some things create time will miss (e.g., in place mods). Does mod time really end up catching more of the more common changes? Would you really need to use both to be sure of catching all changes? Thanks, Mike Michael Zeleznik Computer Science Dept. University of Utah zeleznik@cs.utah.edu Salt Lake City, UT 84112 (801) 581-5617
vijay@apollo.HP.COM (Vijay Sundaram) (08/30/89)
In article <3188@wasatch.utah.edu> zeleznik%cs.utah.edu@wasatch.utah.edu (Mike Zeleznik) writes: >Is there a good reason why wbak uses the mod time of a file instead of its >create time for incrementals? > >The problem is if you "cp -p" in from another machine, or tar stuff in, the >mod times will stay as the original (which is usually what one wants, along >with keeping the modes). But now, in general, these "new" files won't get >backed up til the next full save (unless the mod times happened to be >in the right window). I don't think this would happen with ctime. > >This seems kind of a big hole for people who move things around. > >I understand OmniBack uses mod times also (correct me if I am wrong). > >Is there a reason for not using ctime? Thanks. > >Mike > > Michael Zeleznik Computer Science Dept. > University of Utah > zeleznik@cs.utah.edu Salt Lake City, UT 84112 > (801) 581-5617 OmniBack uses the modified time (dtm) *as well as* the time the attributes were changed (dta). When you do a "cp -p" the modified time remains the same, the time of creation and use gets updated. The dta also gets updated. Since OmniBack looks at whichever was updated from {dta, dtm}, no undue penalty is incurred. -- Vijay-- ------------------------------------------------------------------------------------ Vijay Sundaram vijay%apollo.hp.com Apollo Division of Hewlett-Packard {decwrl!decvax, mit-eddie, attunix}!apollo!vijay ------------------------------------------------------------------------------------