[0] Perl> $a = 0; print size $a;;
24
[0] Perl> $b = pack 'b*', 0; print size $b;;
56
[0] Perl> print Dump $a;;
SV = IV(0x3e74270) at 0x3e74278
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 0

[0] Perl> print Dump $b;;
SV = PV(0x11c110) at 0x3e6c6d8
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x3ecd828 "\0"\0
  CUR = 1
  LEN = 8