Hello,
l'origine de ce comportement se trouve dans la
doc officielle de tar (pas le man) : cela provient vraisemblablement du Blocking Factor (par défaut fixé à 20).
9.4.2 The Blocking Factor of an Archive
The data in an archive is grouped into blocks, which are 512 bytes. Blocks are read and written in whole number multiples called records. The number of blocks in a record (i.e., the size of a record in units of 512 bytes) is called the blocking factor. The `--blocking-factor=512-size' (`-b 512-size') option specifies the blocking factor of an archive. The default blocking factor is typically 20 (i.e., 10240 bytes), but can be specified at installation. To find out the blocking factor of an existing archive, use `tar --list --file=archive-name'. This may not work on some devices.
