Re: freshly installed SW not found

From	William Unruh <unruh@invalid.ca>
Newsgroups	alt.os.linux
Subject	Re: freshly installed SW not found
Date	2019-03-02 07:08 +0000
Organization	A noiseless patient Spider
Message-ID	<q5da66$8vf$1@dont-email.me> (permalink)
References	(6 earlier) <op.zxznlbyza3w0dxdave@hodgins.homeip.net> <q5cfp2$rfr$1@dont-email.me> <op.zxzz16nca3w0dxdave@hodgins.homeip.net> <q5cud4$s7b$1@dont-email.me> <op.zx0ajfcja3w0dxdave@hodgins.homeip.net>

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On 2019-03-02, David W. Hodgins <dwhodgins@nomail.afraid.org> wrote:
> On Fri, 01 Mar 2019 22:47:49 -0500, William Unruh <unruh@invalid.ca> wrote:
>
>> On 2019-03-02, David W. Hodgins <dwhodgins@nomail.afraid.org> wrote:
>>> The first time it's run, yes. It stores the md5 hash values in a file in
>>> the /root directory. After that it only needs to calculate them for new
>>> or changed files.
>
>> But the only way you know if the file is changed is to run the md5hash.
>> That is not fast. Youhave to run the hash on every file every time.
>
> It has options for how to do the comparison. One option is to only
> check the filename, date, and time haven't changed. Another option
> is to do as you've said, and recalculate the hash for every file.
> It's the user's choice.

Agreed. But if you have compressed the file, then the date/time has
changed. Now you could of course set the date/time to the date/time of
the previous file, but that leaves just the length of the compressed
file as the comparison, and that is really very weak. There is a good
chance that the file has changed, but the compressed length has not
changed, and you will not save a change that should be saved. 
Ie, it becomes important that you do the hash as a comparison if you do
not want to loose changes, and that takes a long time for a large file. 
A backup which does not backup some changes is pretty ropy.
Or you could do a traversal of the filesystem again, and set the
time/date of the compressed file the same as the time/date of the
orginal. But you still have to compress the file before you know if it
is the same length as the previous one-- again a long process. And this
now has to be done for every file on the system. 

>
>
>>> Correct, which is the point of including that statement. The decisions
>>> of how to handle backups are very subjective. My point is simply that
>>> there are options available, which people are free to choose to use, if
>>> they suits their needs.
>
>> Of course, but they should be aware of the costs beforehand.
>
> On that I fully agree.
>
> Regards, Dave Hodgins
>

Thread

freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-26 19:47 +0100
  Re: freshly installed SW not found "J.O. Aho" <user@example.net> - 2019-02-26 20:28 +0100
    Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-26 21:51 +0100
      Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-02-26 21:46 +0000
        Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-27 12:52 +0100
          Re: freshly installed SW not found Aragorn <thorongil@telenet.be> - 2019-02-27 12:44 +0000
            Re: freshly installed SW not found Dan Purgert <dan@djph.net> - 2019-02-27 13:27 +0000
            Re: freshly installed SW not found Richard Kettlewell <invalid@invalid.invalid> - 2019-02-27 15:16 +0000
            Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-27 16:59 +0100
              Re: freshly installed SW not found Dan Purgert <dan@djph.net> - 2019-02-27 16:02 +0000
                Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-27 20:46 +0100
                Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-02-27 20:18 +0000
                Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-28 12:47 +0100
                Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-02-28 18:32 +0000
                Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-03-01 01:14 +0100
                Re: freshly installed SW not found "Carlos E.R." <robin_listas@es.invalid> - 2019-03-01 01:54 +0100
                Re: freshly installed SW not found Jasen Betts <jasen@xnet.co.nz> - 2019-03-01 03:09 +0000
                Re: freshly installed SW not found Aragorn <thorongil@telenet.be> - 2019-02-27 20:21 +0000
                Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-02-27 23:02 +0000
                Re: freshly installed SW not found Richard Kettlewell <invalid@invalid.invalid> - 2019-02-27 23:24 +0000
                Re: freshly installed SW not found Jasen Betts <jasen@xnet.co.nz> - 2019-02-28 04:46 +0000
                Re: freshly installed SW not found Dan Purgert <dan@djph.net> - 2019-02-28 10:59 +0000
                Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-28 18:51 +0100
                Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-02-28 18:24 +0000
                Re: freshly installed SW not found Dan Purgert <dan@djph.net> - 2019-03-01 13:49 +0000
                Re: freshly installed SW not found "Carlos E.R." <robin_listas@es.invalid> - 2019-03-01 18:22 +0100
                Re: freshly installed SW not found Aragorn <thorongil@telenet.be> - 2019-03-01 19:06 +0000
                Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-03-03 01:08 +0100
                Re: freshly installed SW not found Aragorn <thorongil@telenet.be> - 2019-03-03 00:14 +0000
                Re: freshly installed SW not found Dan Purgert <dan@djph.net> - 2019-03-03 13:00 +0000
                Re: freshly installed SW not found Dan Purgert <dan@djph.net> - 2019-03-03 12:46 +0000
                Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-02-28 18:15 +0000
              Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-02-27 16:38 +0000
                Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-27 20:51 +0100
              Re: freshly installed SW not found Jasen Betts <jasen@xnet.co.nz> - 2019-02-28 04:39 +0000
        Re: freshly installed SW not found "Carlos E.R." <robin_listas@es.invalid> - 2019-02-27 14:30 +0100
      Re: freshly installed SW not found "J.O. Aho" <user@example.net> - 2019-02-27 07:05 +0100
      Re: freshly installed SW not found "Carlos E.R." <robin_listas@es.invalid> - 2019-02-27 14:29 +0100
        Re: freshly installed SW not found Paul <nospam@needed.invalid> - 2019-02-27 08:50 -0500
          Re: freshly installed SW not found "Carlos E.R." <robin_listas@es.invalid> - 2019-02-28 00:05 +0100
        Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-27 16:56 +0100
        Re: freshly installed SW not found Chris <ithinkiam@gmail.com> - 2019-03-01 14:58 +0000
      Re: freshly installed SW not found Chris <ithinkiam@gmail.com> - 2019-03-01 15:04 +0000
        Re: freshly installed SW not found "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2019-03-01 10:50 -0500
          Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-03-01 18:40 +0000
            Re: freshly installed SW not found "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2019-03-01 14:40 -0500
              Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-03-01 23:38 +0000
                Re: freshly installed SW not found "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2019-03-01 19:09 -0500
                Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-03-02 03:47 +0000
                Re: freshly installed SW not found "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2019-03-01 22:55 -0500
                Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-03-02 07:08 +0000
                Re: freshly installed SW not found "Carlos E.R." <robin_listas@es.invalid> - 2019-03-02 11:27 +0100
                Re: freshly installed SW not found Paul <nospam@needed.invalid> - 2019-03-02 04:10 -0500
                Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-03-02 16:29 +0000
                Re: freshly installed SW not found Paul <nospam@needed.invalid> - 2019-03-02 11:54 -0500
                Re: freshly installed SW not found "Carlos E.R." <robin_listas@es.invalid> - 2019-03-02 11:24 +0100
                Re: freshly installed SW not found Jasen Betts <jasen@xnet.co.nz> - 2019-03-02 00:28 +0000
                Re: freshly installed SW not found "Carlos E.R." <robin_listas@es.invalid> - 2019-03-02 11:31 +0100
                Re: freshly installed SW not found Aragorn <thorongil@telenet.be> - 2019-03-02 11:31 +0000
                Re: freshly installed SW not found Melzzzzz <Melzzzzz@zzzzz.com> - 2019-03-02 11:34 +0000
                Re: freshly installed SW not found Aragorn <thorongil@telenet.be> - 2019-03-02 11:48 +0000
                Re: freshly installed SW not found Melzzzzz <Melzzzzz@zzzzz.com> - 2019-03-02 12:15 +0000
                Re: freshly installed SW not found "Carlos E.R." <robin_listas@es.invalid> - 2019-03-02 23:15 +0100
                Re: freshly installed SW not found Chris Elvidge <chris@mshome.net> - 2019-03-03 00:33 +0000
                Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-03-03 01:38 +0100
                Compressed filesystems [Was: Re: freshly installed SW not found] "Carlos E.R." <robin_listas@es.invalid> - 2019-03-03 13:11 +0100
                Re: Compressed filesystems [Was: Re: freshly installed SW not found] Soviet_Mario <SovietMario@CCCP.MIR> - 2019-03-03 19:49 +0100
                Re: Compressed filesystems [Was: Re: freshly installed SW not found] "Carlos E.R." <robin_listas@es.invalid> - 2019-03-03 21:17 +0100
                Re: freshly installed SW not found Dan Purgert <dan@djph.net> - 2019-03-03 12:49 +0000
                Re: freshly installed SW not found Melzzzzz <Melzzzzz@zzzzz.com> - 2019-03-03 12:35 +0000
            Re: freshly installed SW not found "Carlos E.R." <robin_listas@es.invalid> - 2019-03-02 11:22 +0100
  Re: freshly installed SW not found Wildman <best_lay@yahoo.com> - 2019-02-26 13:31 -0600
    Re: freshly installed SW not found Wildman <best_lay@yahoo.com> - 2019-02-26 15:42 -0600
      Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-02-26 21:51 +0000
  Re: freshly installed SW not found "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2019-02-26 14:36 -0500
    Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-26 21:58 +0100
      Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-02-26 21:49 +0000
        Re: freshly installed SW not found Soviet_Mario <SovietMario@CCCP.MIR> - 2019-02-27 12:54 +0100
  Re: freshly installed SW not found William Unruh <unruh@invalid.ca> - 2019-02-26 19:51 +0000

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