-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 El 2014-08-06 a las 11:04 -0400, Anton Aylward escribió:
On 08/06/2014 10:06 AM, Carlos E. R. wrote:
That problem with .taz is that they tar up the files and then compress that resulting .tar file.
Correct. There is an alternate procedure, with cpio, to compress files first, then archive the result. If there is damage it typically only affects one file. The other way round, the problem is that you simply can not expand the gzip compression if one byte is damaged - I have been bitten by that. It is possible, though, that the location of the damage is critical, as you say, metadata vs payload. I dunno.
I have not ever seen a Linux backup utility that implements both compression and forward data recovery methods - such as used, for example, by pctools backup, back in the 80's, with good results.
Good point. But I wonder if many of those DOS/Windows tools used the separate metadata vs compressed data I spoke of?
I have recovered sucesfully backup sets done 15 years before using about 80 flopies, with damaged, bad sectors. The software was able to recover everything, after some thinking. Of course, this particular software also used code of their own to manage the flopy drive unit. They did not use msdos for it. It would be curious to learn what they did... I have the very strong feeling they changed the floppy format metadata as well. They also did tape backups, I think, but I did not have a unit at that time. Too expensive for me. - -- Cheers Carlos E. R. (from 13.1 x86_64 "Bottle" (Minas Tirith)) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iF4EAREIAAYFAlPiWUQACgkQja8UbcUWM1w9QwD/RLsZ3nZNF656nUCabo6ycagS jiCrQGpU/1cocGfxraQA/AphajTmpAlfAr0Wi6wR+69LNBmZlC9BTKSdRonuGf6z =6C4x -----END PGP SIGNATURE-----