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"... Because tar does not support encryption/compression on the inside of archives ..." That can be an advantage. Space isn't always what I want for backups -

"... Because tar does not support encryption/compression on the inside of archives ..." That can be an advantage. Space isn't always what I want for backups - I want the original data back and compression gone wrong (tar -zxvf) is just another way to loose data.

fhars 16y ago
That is exactly why the lackof in-archive compression is bad, with tar you lose tje whole rest of the archive on a single bit error, with in-archive compression you lose just the file the error is located in.
- btilly 16y ago
  Also tar's behavior gives you better compression in the common (at least on Unix) case of many small text files with related content. In other words the trade-off is exactly the opposite of what had been guessed above.
masklinn 16y ago
> That can be an advantage. Space isn't always what I want for backups Most if not all "compression" formats (and software) offer a "store" compressor which stores the data as-is, without applying any compression filter.
dagw 16y ago
The pkzip format allows you to "zip" data uncompressed if you are worried about that. Then you can trivially unpack your files using nothing but seek and read for those cases where you also accidentally misplace your last copy of unzip.
- bootload 16y ago
  "... The pkzip format allows you to "zip" data uncompressed if you are worried about that. ..." Didn't know that & must check the docs again.
  - nitrogen 16y ago
    Some Zip applications show uncompressed files as being compressed with the "Store" algorithm instead of "Deflate".
- acqq 16y ago
  It also has file description before the copy of the file data and at the second copy at the end of the whole archive, allowing fast listing of the content or location inside of the archive, exactly as the article would want. The only thing pkzip doesn't cover in the original format is unix/linux specific metadata, but maybe this was/can be added. I use info-zip when the metadata don't matter but tar when they do (but even tar has its limitations with working with unix/linux metadata).
  - dagw 16y ago
    pkzip does reserve the posibility for an arbitrary length extra field connected to each file. According to the spec (http://www.pkware.com/documents/casestudies/APPNOTE.TXT http://www.pkware.com/documents/casestudies/APPNOTE.TXT) this is for "additional information...for special needs or for specific platforms". All compatible zip tools are required to ignore all information in this field that it doesn't understand so you can basically write whatever you want there (although the spec does offer a recommended format for writing to this field). So if you write a special ACL preserving zip implementation, you can still unpack the file with any other zip implementation that knows nothing of your special version.
gaius 16y ago
tar never cared about encryption or compression because mostly you would get them "for free" in your tape library anyway. http://en.wikipedia.org/wiki/Linear_Tape-Open#Compression http://en.wikipedia.org/wiki/Linear_Tape-Open#Compression

fhars 16y ago

That is exactly why the lackof in-archive compression is bad, with tar you lose tje whole rest of the archive on a single bit error, with in-archive compression you lose just the file the error is located in.

btilly 16y ago
Also tar's behavior gives you better compression in the common (at least on Unix) case of many small text files with related content. In other words the trade-off is exactly the opposite of what had been guessed above.

masklinn 16y ago

> That can be an advantage. Space isn't always what I want for backups Most if not all "compression" formats (and software) offer a "store" compressor which stores the data as-is, without applying any compression filter.

dagw 16y ago

The pkzip format allows you to "zip" data uncompressed if you are worried about that. Then you can trivially unpack your files using nothing but seek and read for those cases where you also accidentally misplace your last copy of unzip.

bootload 16y ago
"... The pkzip format allows you to "zip" data uncompressed if you are worried about that. ..." Didn't know that & must check the docs again.
- nitrogen 16y ago
  Some Zip applications show uncompressed files as being compressed with the "Store" algorithm instead of "Deflate".
acqq 16y ago
It also has file description before the copy of the file data and at the second copy at the end of the whole archive, allowing fast listing of the content or location inside of the archive, exactly as the article would want. The only thing pkzip doesn't cover in the original format is unix/linux specific metadata, but maybe this was/can be added. I use info-zip when the metadata don't matter but tar when they do (but even tar has its limitations with working with unix/linux metadata).
- dagw 16y ago
  pkzip does reserve the posibility for an arbitrary length extra field connected to each file. According to the spec (http://www.pkware.com/documents/casestudies/APPNOTE.TXT http://www.pkware.com/documents/casestudies/APPNOTE.TXT) this is for "additional information...for special needs or for specific platforms". All compatible zip tools are required to ignore all information in this field that it doesn't understand so you can basically write whatever you want there (although the spec does offer a recommended format for writing to this field). So if you write a special ACL preserving zip implementation, you can still unpack the file with any other zip implementation that knows nothing of your special version.

gaius 16y ago

tar never cared about encryption or compression because mostly you would get them "for free" in your tape library anyway. http://en.wikipedia.org/wiki/Linear_Tape-Open#Compression http://en.wikipedia.org/wiki/Linear_Tape-Open#Compression