can somone explain what iso bin cue and the rest

[jnj]

hi i'm asking what are bin iso cue you don't get any of that with psx but dreamcast you realy have to dream i brought my son a DC for chistmas and he's scraced 2 games now i go searching the web and you hear of bin etc etc
what are they all and how can i back up the other 4 games cause i can't afford to replace the other ones

Thanks To Anyone That Can Help