dd bs [was: Re: Help]

[V13]

On Thursday 23 July 2009, Christos Ricudis wrote:
> dd if=/dev/sda of=/tmp/sda-image-original.img bs=16384
>
> (bs σημαινει block size. Το 16384 ειναι καλο νουμερο για δισκους).

Erotisi kriseos: Os gnoston to na baleis os bs ena mikro noymero timoreitai me 
mastigoma. To na baleis omos ena megalo noymero (prosopika protimo to 1024000) 
den exei akribos ta idia apotelesmata me to na baleis kati san to 16384? 
Logika o kernel spaei ta writes opos nomizei opote to apotelesma einai to 
idio. An nai tote glitoneis apo to mazoxismo ton diereseon me to 16384 (esto 
kai an ginontai me apla right-shift :P). To mono problima poy mporo na 
fantasto einai na kanei h dd write() gia 1024000 bytes kai na grafontai (p.x.) 
ta 1023000 oste na menoyn 1000 bytes gia grapsimo kai na xreiazetai kai 
deytero write(). Me 1MB writes den nomizo na symbainei kati tetoio. To strace 
deixnei:

write(1,"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
1024000) = 1024000

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