ivalentin
/
V-Gears


			
				
					
						
						
							123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475
							<html>
    <head>
        <link rel="stylesheet" href="style.css"/>
    </head>
    <body>
        <h2>Kernel Overview</h2>
        <h3>History</h3>
        <p>
            The kernel is a throwback to the very first Final Fantasy game for
            the Nintendo's original 8 bit system. The NES could only natively
            read 32 kilobytes of program ROM. To get around this incredible
            limitation, Nintendo developed "memory mappers" that allowed parts
            of the program to be switched out, or "banked" and replaced with
            other parts stored on the game cartridge.
        </p>
        <p>
            FF1 used Nintendo's "Memory Manager Controller #1" (MMC1) . This
            controller split the game into sixteen sections, each 16 kilobytes
            long. (The maximum an MMC1 program could be was 256K). This
            controller also split the accessible memory from the cartridge into
            two 16K sections. The top 16K was bankable. The bottom 16K could
            never be switched out and stayed in memory until you removed the
            cartridge.
        </p>
        <p>
            The original FF1 kernel was located in this bottom 16K of memory.
        </p>
        <p>
            First and foremost the kernel contained the main program loop. It
            handled all the low level functions for the game. Some of these
            included controlling interrupts, banking in and out the appropriate
            part of the game, jumping control to a particular module, playing
            the music, and other tasks.
        </p>
        <p>
            As the Final Fantasy franchise grew, so did the size of the games.
            They all still retained the kernel/module system. During the
            backporting process, this did cause a few headaches. For example,
            Final Fantasy 6 was originally developed for the Super Nintendo.
            When it's menu module was banked in, it was done with electronic
            bank switching. The later PSX port banked the data from the CD-ROM,
            which caused an unexpected lag that one wasn't used to. On the PC
            version for FF7, them menu system was simply integrated into the
            main executable.
        </p>
        <h3>Kernel Functionality</h3>
        <p>
            The Kernel is a threaded multitasking program that manages the
            whole system. It uses a simple software based memory manager that
            handles both RAM and video memory for all the modules in the game.
            Assisting the kernel are many statically linked Psy-Q libraries. In
            the case of the PC port, the Psy-Q libs were replaced with a PC
            equivalent. For example the SEQ player was replaced with a MIDI
            player, Both accomplish the same tasks, just with different formats
            and execution strategies. The table below is a generic
            representation of how the kernel sits in relation to the other
            aspects of the program.

        </p>
        <p>
            <table id='kernel-functionality'>
                <tr><td>User</td></tr>
                <tr><td>Module</td></tr>
                <tr>
                    <td>
                        Kernel
                        <span id='kernel-psyq'>Psy-Q libraries</span>
                    </td>
                </tr>
                <tr><td>PSX BIOS</td></tr>
                <tr><td>Hardware</td></tr>
            </table>
        </p>
    </body>
</html>