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→PSX CD-ROM management
One of the big rules on PSX development is direct hardware access is a prohibited. Everything must go through the BIOS or the program will risk being incompatible with later systems. This means not only the from PSX to PS2, but also all the trivial hardware revisions as well. This creates a problem for the kernel. During module transitions, (For example, going from "Map" to "Battle"), the engine actually "preloads" the next module while the current one is still executing. This loading of data can't be done with a simple open() or read() BIOS syscall. Whenever you enter the BIOS, the rest of the system comes to a screeching halt until it is exited.
This problem is solved by the FF7 actually controlling the CD-ROM access itself though faster, low-level BIOS calls. The kernel can only load 8 kilobytes at a time in this "quick mode" The in In this mode the kernel also only references files by what sector of the CD-ROM the data is located on, not by filename.
