Re: [Bug-tar] Possible tar bug

[bocek . pavel]

I used -cMf for the very first tape, than I continued with -rMf for adding new 
files, shouldn't this make the whole huge archive in correct format? I mean, 
when I set to append, it should continue using the same format as the previous 
record has, overwriting everything what was on the tape after the last record, 
shouldn't it?

> ------------ Původní zpráva ------------
> Od: Paul Eggert <address@hidden>
> Předmět: Re: [Bug-tar] Possible tar bug
> Datum: 26.12.2010 23:01:18
> ----------------------------------------
> On 12/26/2010 11:40 AM, address@hidden wrote:
> > The -r option is extactly what I want since with it the tar appends to end 
> > of
> archive.
>
> OK, but you're wearing out the tape drive unnecessarily, since it
> reads the whole tape.  It'd be much faster to seek to the end of
> the file on the tape, go back two blocks (for tar's EOF marker),
> and then start tar from there.  And it'd be even faster simply
> to append a new tar image to the tape, so that the tape contains
> multiple files.
>
> Anyway, I suspect your tape got polluted with a ustar-format
> archive; perhaps you used another version of tar, or tar with
> some unusual options, to create it in the first place; or maybe
> it just had some leftover data on it that happened to look like
> a ustar-format archive.  To avoid this problem in the future,
> please make sure you use 'tar -c' the first time you write to
> the tape, and use 'tar -r' only after the tape is safely initialized.
>
>
>