Question

[17rajam123]

What type of os does the ps2 run?

And what are the bios for the ps2?

Is the pcsx2 running off a visual studio compiler?

[Blyss Sarania]

The PS2 doesn't run an OS per say. It runs a very stripped down sort of pre boot environment you can say. That "OS" is stored in the BIOS. The BIOS is a chip in the PS2 that contains said "OS", as well as C runtime libraries, the PSX BIOS, some modules to interface with the hardware and a few other things. Some of that stuff(like the modules) can be soft updated on boot by a game. Many games contain updated IRX modules for this purpose for instance.

Nothing "runs off a compiler." A compiler generates code to be run on a CPU. The same code can be compiled by different compilers for different target CPUs. Assuming the code doesn't use platform specific stuff, you can compile the same code for a PC CPU and then compile it for a smartphone CPU and then compile it for a PS3.

[gregory]

The PS2 has
* a boot sequence (aka bios)
* 1 EE kernel (aka OS number 1)
* 1 IOP kernel (aka OS number 2)
* Various modules (aka peripheral drivers + common code such as the lib C).
* Others modules to "emulate/virtualize" the PSX

Actually what is wrongly named BIOS is the ROM code.