Re: [Gnu-arch-users] Re: patch-log sizes

[Tupshin Harper]

Thomas Zander wrote:

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> > This reminds me of a question that I've been meaning to ask for some
> > time. Is there a strong reason why it makes sense for arch to store
> > files in compressed tars as opposed to storing compressed files in
> > uncompressed tars? Specifically, the difference between a .tgz
> > containing many .txt files vs a .tar containg many .txt.gz files.
> > (Extensions used just to illustrate the fundamental nature of the files
> > in question). Presumably compression ratios would be somewhat less, but
> > accessing a limited subset of the files in the tar would be *much*
> > cheaper.
> >
> > Any thoughts? What am I missing?
> >    
>
> Did you research this; since research on my part (actually by the 
> OpenOffice group) showed that this is not cheaper at all..
>  
Your post reminded me of what I was missing. I'd forgotten that tar 
doesn't contain any index into it's contents (unlike zip), and therefore 
extracting a single file would still require a linear seek through the 
contents looking for the one file that you want to extract. CPU 
utilization would go down since you only gunzip one file, but disk 
access would be the bottleneck, and would be unaffected or be made worse 
by this strategy. Sigh...tar sucks.

-Tupshin