Michael Wiktowy wrote:
On 10/29/07, Robin Laing <Robin.Laing@xxxxxxxxxxxxxxx> wrote:
I would love an open source program that does what RAR files do. With
the addition of PAR2 files, the RAR files or compressed files can be
repaired.
...
The problem is RAR is used heavily in usenet. RAR is not only a
compression tool but a splitter and a great archiving tool.
FWIW, there is a rpm "par2cmdline" that generates and works with par2
files. This is part of Fedora.
From what I have read about rar, all the rar pieces are simply one
archive that has been binary chopped up into n pieces. You can do that
with any archive with the "split" command and then "cat" them back
together. I have done that to chop up a large disk image to avoid the
2GB/file limit on FAT32 external backup drives:
dd if=/dev/partition_to_be_read_from | gzip -c \
| split -b 2000m - /mnt/usb/image_name.img.gz.
Then to combine them:
cat /mnt/usb/image_name.img.gz.* \
| gzip -dc | dd of=/dev/partition_to_be_written_to
/Mike
True but rar will also create parity blocks to check and repair the
split files.
As I understand it, RAR is a form of RAID for archiving files on
different media. It then started getting used on usenet for sending
large bin files. Vary useful as you can check and repair the files.
From http://en.wikipedia.org/wiki/RAR_(file_format)
"Variable amounts of redundancy (“recovery record”) can be added to an
archive, making it more resistant to corruption. Even if parts of an
archive are damaged, it is possible to fully recover the stored data if
a large enough recovery record exists."
Can this be done with gz?
Of course a gz file could be run through par2 and have redundancy blocks
created. I guess this could then be done with any file allowing pgp
encrypted files to be repaired.
--
Robin Laing
