NEC PC-9800

• Emulator: RetroArch
• Core: libretro: np2kai
• Folder: /userdata/roms/pc98
• Accepted ROM formats: .d98, .zip, .98d, .fdi, .fdd, .2hd, .tfd, .d88, .88d, .hdm, .xdf, .dup, .cmd, .hdi, .thd, .nhd, .hdd, .hdn, .m3u

Required BIOS files:

Optional BIOS files:

Place your NEC PC-9800 ROMs in /userdata/roms/pc98.

Software for the PC-98 was delivered typically via floppy disk drives (you remember those, right?) which would then install their software onto the hard-drive. For this reason, PC-98 ROMs can come in either their original floppy disk image (to be installed) or the game data as it was post-installation (an image of the hard-drive). If given the choice, it is easier to work with hard-drive images.

Using hard-drive images is pretty simple, just load the single file and play. Batocera will take care of most of the configuration for you.

List of formats PC-98 hard-drive images typically come in:

• HDI
• HDM
• NHD
• 2HD
• and more…

These are harder to work with as they require all of the floppy disk images for that particular piece of software (typically, most software was distributed on multiple floppy disks due to their limited storage).

List of formats PC-98 floppy disk images typically come in:

• FDI
• FDM
• NFD
• D88
• and more…

These are rare but sometimes the only method available to rip the game at the time was to put all the raw data onto a CD image. Games in this format cannot be loaded by NPIIKai, and must be put into either a HDI by a PC-98 hard-disk image exploring tool or something else.

RetroArch (formerly SSNES), is a ubiquitous frontend that can run multiple “cores”, which are essentially the emulators themselves. The most common cores use the libretro API, so that's why cores run in RetroArch in Batocera are referred to as “libretro: (core name)”. RetroArch aims to unify the feature set of all libretro cores and offer a universal, familiar interface independent of platform.

RetroArch offers a Quick Menu accessed by pressing [HOTKEY] + which can be used to alter various things like RetroArch and core options, and controller mapping. Most RetroArch related settings can be altered from Batocera's EmulationStation.

Standardized features available to all libretro cores: pc98.videomode, pc98.ratio, pc98.smooth, pc98.shaders, pc98.decoration, pc98.game_translation

Neko Project II Kai is a fork of the original Neko Project II PC-98 emulator. Currently the definitive PC-98 emulator, in libretro form.

The NP2 menu can be opened by pressing [L2], however this shouldn't be required as Batocera can handle the configuration of the important settings in its PER SYSTEM ADVANCED OPTIONS. It's still fun to look at for that retro Windows look, though.

If a particular game isn't working (or is displaying double images), most of the time it's the GDC clock that needs to be adjusted. Thankfully, there are only two modes, so even though the menu is in Japanese it should be easy to tell them apart.

1. Open the game.
2. During the PC-98's booting procedure, hold down the [End] key. This will open up the PC-98's BIOS menu. In case you missed it, you can restart ( [HOTKEY] + ) to try again.
3. Select ディップスイッチ２ using the arrow keys and press Enter.
4. Select the GDC option and press the right arrow key to switch to 2.5MHz (the default setting is 5Mhz).
5. To return, select 終了 (the bottom-most option) and press Enter. Go to 終了 again and select it to reboot the PC-98 system.

Most games would default to assuming the player only had a mouse and keyboard, so the default Joy2Key profiles (with the Z and X keys bound to the controller's face) should be sufficient. In the case that a game requires the full set of keys, the “Manual Keyboard” Joy2Key profile should be used (along with a real keyboard, the Batocera RetroPad doesn't have enough buttons unfortunately).

Here are the default NEC PC-9800's controls shown on a Batocera RetroPad:

Batocera Retropad	Joy2Key Arrows	Joy2Key Keypad	Joy2Key Mouse
	Z key	Z key	Mouse Left-click
	X key	X key	Mouse Right-click
	Left Control key	Left Control key
	Space key	Space key
[START]	Return key	Return key
[SELECT]	Escape key	Escape key
D-pad Up	↑ key	Keypad 8 key (↑)	Move cursor up
D-pad Down	↓ key	Keypad 2 key (↓)	Move cursor down
D-pad Left	← key	Keypad 4 key (←)	Move cursor left
D-pad Right	→ key	Keypad 6 key (→)	Move cursor right
[L1]	Backspace key	Backspace key	Increase cursor speed
[R1]	Right Shift key	Right Shift key
[R2]	Open the NP2 menu	Open the NP2 menu

The original PC-98 mice did not have a middle-click, so the middle-click here (should you use it) will also open the NP2 menu.

Most games should handle this automatically, but some may need to be launched manually after being loaded. The process is surprisingly similar to MS-DOS.

1. Type DIR /p and press [Enter]. A list of files on the disc should be displayed.
   1. In order to navigate into subfolders, type cd <FOLDERNAME> and press [Enter].
2. Search for the game's executable file. Typically it is a BAT file named an abbreviation/shortening of the game's title.
3. Type this filename in and press [Enter]. Cross your fingers. If it didn't work, try other files until you find the one that does.

The PC-98 ran at a very unusual framerate of around 55Hz, which doesn't fit in nicely with 50Hz nor 60Hz displays. Luckily, if you have a display that supports variable refresh rate (like Freesync) then it should be easy enough to just activate that option within RetroArch to achieve the exact same framerates as the original machines did.

In case you need to return your BIOS settings back to default, simply open the BIOS menu and press the Home key. This will restore everything to their default values.

Well it is a Japanese computer. A small amount of PC-98 games have English fan-translations available, others may be found by using a search engine.

In case there isn't a translation available for your game yet, you can always use Batocera/RetroArch's AI game translation option, to varying degrees of success. Japanese-to-English is one of the more difficult translations for the AI to do.

For further troubleshooting, refer to the generic support pages.