Data kitaalamu zinakua stored in binary form, ones or zeros (1's,0's),on or off,Actualy,hufuti data kwenye digital camera,HDD nk,bali inakua flaged(marked) as free,ambapo uko mbeleni inaweza kuja kuwa overwritten na data nyingine.
Nikisungumzia zaidi mechanisim ya disk drives kama HDD etc, zile bit of data zinakua arranged in concentric, circular paths zinazoitwa 'tracks',kila track inavunjwa katika sehemu ndogo ndogo zinazoitwa 'sectors',sasa kuna kipart cha disk drive kinastore map za sectors zilizotumika na zilizo free,kwenye os kama ,(linux hiyo map inaitwa 'ext'(extended file sytem) na windows inaitwa FAT(file allocation table) au MFT(master file table){for NTFS}),hizi sector zinakua zimebebana,'imagine chapati zilizobebana'.Sasa zikiwa overwritten sana zina evaporate tu(hapa sijui zinaenda wapi),so kwamfano ukifuta file na ukawahi kurecovery,data zako unazipata kama kawa.