I tarred, and re-tarred, the same directory. 2,560 bytes of metadata is somehow lost in that simple process:
/tmp$ tar xf workArea.tar
/tmp$ tar cf workArea_copy.tar WorkArea
/tmp$ ls -l *tar
-rw-r--r-- 1 jdoe wheel 2068480 Mar 19 22:54 workArea.tar
-rw-r--r-- 1 jdoe wheel 2065920 Mar 19 23:27 workArea_copy.tar
/tmp$
How can there be data loss???
But then, I un-tarred / re-tarred workArea_copy.tar
, and there was no data loss:
/tmp$ tar xf workArea_copy.tar
/tmp$ tar cf copy_copy.tar WorkArea
/tmp$ ls -l *tar
-rw-r--r-- 1 jdoe wheel 2065920 Mar 19 23:38 copy_copy.tar
-rw-r--r-- 1 jdoe wheel 2065920 Mar 19 23:27 workArea_copy.tar
/tmp$
I noticed in the tar
verbose output of when I untarred the original workArea.tar
that some files did not have resource forks:
/tmp$ tar xfv workArea.tar
x WorkArea/
x WorkArea/kjDesc.txt // <-- where is resource fork?
x WorkArea/._engGrammar.doc
x WorkArea/engGrammar.doc
x WorkArea/._gingers.txt
x WorkArea/gingers.txt
x WorkArea/._intro.docx
x WorkArea/intro.docx
x WorkArea/._myAntenna.doc
x WorkArea/myAntenna.doc
x WorkArea/notes.txt // <-- where is resource fork?
x WorkArea/._notesKj.txt
x WorkArea/notesKj.txt
x WorkArea/._queen.xlsx
x WorkArea/queen.xlsx
x WorkArea/trans.txt // <-- where is resource fork?
x WorkArea/._url.txt
x WorkArea/url.txt
/tmp$
However, in the verbose tar
output I can see that the missing resource fork issue exists in both untarring workArea.tar
and workArea_copy.tar
. The verbose output is exactly the same.
All files in this tar file were created on my MacBook. Nothing was imported from other file systems.
- I am sure that 2,560 bytes is metadata. But what metadata?
workArea.tar
andworkArea_copy.tar
both have the same missing meta-data, yet they have difference sizes. I don't get it. - For that matter, how might some files even end-up with missing resource forks in the first place?
thanks.