[Info-vax] backup /image on Windows or Unix?

[Jan-Erik Soderholm]

Bill Gunshannon wrote 2013-01-23 16:27:
> In article <kdorln$bsu$2 at dont-email.me>,
> 	Simon Clubley <clubley at remove_me.eisner.decus.org-Earth.UFP> writes:
>> On 2013-01-23, Dirk Munk <munk at home.nl> wrote:
>>> One of the nicest features of VMS is backup/image. Take a badly
>>> fragmented disk as input, and you will get a beautiful structured disk
>>> as output, all files contiguous etc.
>>>
>>> I have always been looking for utilities that can do the same in Windows
>>> and Unix, but I never found them.
>>>
>>
>> In Unix land have you considered a dump and restore sequence ?
>
> Or the fact that defragmentation is seldom if ever needed on Unix filesystems.
>
> ** /dev/ad4s1a
> ** Last Mounted on /
> ** Root file system
> 2138 files, 286668 used, 219819 free (2883 frags, 27117 blocks, 0.6% fragmentati
> on)
>
> ** /dev/ad4s1e
> ** Last Mounted on /tmp
> 18 files, 21 used, 506466 free (34 frags, 63304 blocks, 0.0% fragmentation)
>
> ** /dev/ad4s1f
> ** Last Mounted on /usr
> 511196 files, 9230891 used, 23406146 free (77194 frags, 2916119 blocks, 0.2% fra
> gmentation)
>
> ** /dev/ad4s1d
> ** Last Mounted on /var
> 28558 files, 91462 used, 2657823 free (23015 frags, 329351 blocks, 0.8% fragment
> ation)
>
> ** /dev/da0s1d
> ** Last Mounted on /archive
> 241149 files, 93064509 used, 143440310 free (9678 frags, 17928829 blocks, 0.0% f
> ragmentation)
>
> ** /dev/ar0s1d
> ** Last Mounted on /users
> 1128838 files, 150083077 used, 86421742 free (166710 frags, 10781879 blocks, 0.1
> % fragmentation)
>
> bill
>

How is that "n.n % fragmentation calculated ?