Is there any way to play back up playstation 2 games without a mod chip

[Pazma]

or other hardware? What exactly is the purpose of a mod chip, what exactly does it do?

Thanks in advance.

[Steph j]

No need for a mod chip when you use SwapMagic. See here for details.
http://www.ecskent.co.uk/ps2/html/swap_magic.html