The Internet Archive is a digital library that provides access to a vast collection of cultural and historical content, including books, movies, music, and video games. One of the items available on the Internet Archive is the PlayStation Portable (PSP) CHD (Compressed Hunk of Data) files, which are related to the emulation of PSP games.

Legacy Formats: If you require older compatibility for a real PSP, some archives still maintain the psp-cso-collection for standard compressed files. Requirements for Use

psp-chd-zstd-redump-part1 directory listing - Internet Archive

Space Saving: A PSP CHD can reduce the size of a standard ISO by 20% to 50%, depending on the game’s data structure.