Gran: Turismo 4 Ps4 Pkg
On a standard, retail PS4, you cannot play PS2 discs. However, the PS4 utilizes a built-in PS2 emulator (known as ps2_netemu ). Sony used this to sell "PS2 Classics" digitally.
This guide provides an educational overview of how this process works technically and the requirements involved. Gran Turismo 4 Ps4 Pkg
