[ILUG] Does afio work with cdrecord?

Brian Foster blf at blf.utvinternet.ie
Fri Aug 26 18:08:47 IST 2005


  | Date: Fri, 26 Aug 2005 11:50:03 +0100
  | From: P at draigBrady.com
  | 
  | Patrick Stack wrote:
  | > I'm trying to backup my /home directory prior to upgrading FC4 using
  | > afio with cdrecord with no success.
  | > I'm using the following command which I've adapted from the example
  | > given in [ afio(1) ].
  | > find /home/patrick/* | afio -o -b -K -b 2048 -s 614400x '!cdrecord dev=0,0,0 -'
  | > 
  | > This seems to work and checks the data (-K) [ ... ]

 why do you think it “works“?
 why do you think it really is checking the data?
 what, in fact, do you think it is doing when
 checking the data?

 like Pádraig, I've never used afio(1) either,
 but I suspect at least part of the problem is
 the `-K'.  it is very likely — and the manual
 page (for v2.5) implies this — that `-K' does
 read-after-write verification.  it is unclear
 if it verifies on a sector-by-sector or image-
 by-image basis, but in either case, it cannot
 possibly work.

 to start with the obvious, `afio' has _no_idea_
 what device to read back!   and then, _if_ it is
 sector-by-sector, it clearly cannot work:  you
 cannot read a CD that is still in the process
 of being recorded.

 the example of using cdrecord(1) in afio(1) does
 not use `-K'.

  |[ ... ]
  | I've never used afio but I think the problem is
  | that cdrecord expects iso images not arbitrary data.

 eh?  AFAIK, in `-data' mode (which is the default),
 `cdrecord' simply writes a data-format CD, and does
 not give a hoot what about the format of the image.
 e.g., I have CDs that are tar(1) images, albeit I
 did not burn them and do not know if `cdrecord'
 or something else was used:  but they do prove
 data-format and ISO-9660 are not isomorphic.

 having said that, I concur Patrick should write
 ISO-9660 (Rockridge) images.  there may be only
 one file in the ISO-9660 — an `afio' archive —
 but the containing software format should be
 ISO-9660, unless there is a Very Good reason
 to the contrary.

cheers!
	-blf-
-- 
Experienced (20+ yrs) kernel/software Eng: | Brian Foster   Montpellier,
 • Unix, embedded, &tc;  • Linux;  • doc;  | blf at utvinternet.ie   FRANCE
 • IDL, automated testing, process, &tc.   |  Stop E$$o (ExxonMobile)!
Résumé (CV) http://www.blf.utvinternet.ie  |     http://www.stopesso.com



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