2023/08/06 23:37 1/7 NEC PC-9800

NEC PC-9800
The NEC PC-9800 (a.k.a. PC-9800シリーズ, Pī Shī Kyūsen
Happyaku Shirīzu or just PC-98) is a family of 16/32-bit computers
developed by NEC. The first model, the PC-9801, was released
(mostly) exclusively in Japan on October 1982, and the last model
was discontinued in 2003. Notable titles include Daisenryaku,
Romance of the Three Kingdoms, 46 Okunen Monogatari: The
Shinkaron, Policenauts and the Touhou Project. It's also home
to a lot of a certain kind of visual novels. A lot.

Check out the PC-98 model list on Wikipedia.

Aimed at business use, in an ironic twist of events it became the

dominant personal home PC in the Japanese market, with over 18
million units having being sold by 1999. It had a healthy
homebrew scene (thanks in part to its completely free licensing
scheme), with many game developers self-publishing games.
Being an x86-based computer, it was technically possible to run a
localized version of MS-DOS and thus Microsoft Windows, though
demand for this particular feature wasn't too high.

This system scrapes metadata for the “pc98” group and loads the
pc98 set from the currently selected theme, if available.

Quick reference

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

BIOS

Required BIOS files:

MD5 checksum Share file path Description

e246140dec5124c5e404869a84caefce bios/np2kai/BIOS.ROM
2af6179d7de4893ea0b705c00e9a98d6 bios/np2kai/FONT.ROM Alternative font file
caf90f22197aed6f14c471c21e64658d bios/np2kai/SOUND.ROM
e9fc3890963b12cf15d0a2eea5815b72 bios/np2kai/ITF.ROM
7da1e5b7c482d4108d22a5b09631d967 bios/np2kai/font.bmp A BMP of the raster font

Optional BIOS files:

Batocera.linux - Wiki - https://wiki.batocera.org/

Last update: 2021/12/20 12:45 systems:pc98 https://wiki.batocera.org/systems:pc98

MD5 checksum Share file path Description

bios/np2kai/bios9821.rom PC-9821 BIOS
bios/np2kai/d8000.rom
bios/np2kai/2608_BD.WAV YM2608 RYTHM sample
bios/np2kai/2608_SD.WAV YM2608 RYTHM sample
bios/np2kai/2608_TOP.WAV YM2608 RYTHM sample
bios/np2kai/2608_HH.WAV YM2608 RYTHM sample
bios/np2kai/2608_TOM.WAV YM2608 RYTHM sample
bios/np2kai/2608_RIM.WAV YM2608 RYTHM sample

ROMs

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.

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…

Floppy disk images

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).

How are these loaded? Need to test.

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

FDI
FDM

https://wiki.batocera.org/ Printed on 2023/08/06 23:37

2023/08/06 23:37 3/7 NEC PC-9800

NFD
D88
and more…

Raw CD images

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.

todo: how to do this

Emulators

RetroArch

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 configuration

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

ES setting name batocera.conf_key Description ⇒ ES option key_value

Settings that apply to all cores of this emulator
Choose which graphics API library to use. Vulkan is
GRAPHICS API pc98.gfxbackend better, when supported.
⇒ OpenGL opengl, Vulkan vulkan.
In milliseconds. Can reduce crackling/cutting out.
AUDIO LATENCY pc98.audio_latency ⇒ 256 256, 192 192, 128 128, 64 64, 32 32, 16 16, 8
8.
Improves performance at the cost of latency and more
THREADED VIDEO pc98.video_threaded video stuttering.
⇒ On true, Off false.

Batocera.linux - Wiki - https://wiki.batocera.org/

Last update: 2021/12/20 12:45 systems:pc98 https://wiki.batocera.org/systems:pc98

libretro: np2kai

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.

libretro: np2kai configuration

ES setting name
Description ⇒ ES option key_value
batocera.conf_key
Settings that apply to all systems this core supports

PC MODEL global.np2kai_model ⇒ PC-286 PC-286, PC-9801VM PC-9801VM, PC-9801VX

PC-9801VX.
Select the processor model.
⇒ Intel 80386 Intel 80386, Intel i486DX Intel i486DX,
CPU FEATURE Intel Pentium (MMX) Intel MMX Pentium, Intel Pentium 2
global.np2kai_cpu_feature Intel Pentium II, Intel Pentium 3 Intel Pentium
III, Intel Pentium 4 Intel Pentium 4, Neko Processor II
Neko Processor II.
Most games work fine with overclock multipliers up to 42x.
32x is a more conservative setting. For certain games, it is
really only feasible to use very low overclock multipliers as
OVERCLOCK MULTIPLIER
otherwise they run too fast.
global.np2kai_clk_mult
⇒ 2x 2, 4x 4, 5x 5, 6x (Recommended) 6, 8x 8, 10x 10, 12x
12, 16x 16, 20x 20, 24x 24, 30x 30, 36x 36, 40x 40, 42x 42,
52x 52, 64x 64, 76x 76, 88x 88, 100x 100.

EMULATED RAM SIZE ⇒ 1MB 1, 3MB 2, 7MB 7, 11MB 11, 13MB (Recommended)
global.np2kai_ExMemory 13, 16MB 16, 32MB 32, 64MB 64, 120MB 120, 230MB 230,
512MB 512, 1024MB 1024.
Graphic Display Controller model. In order to change its clock
GDC global.np2kai_gdc speed, refer to its specific section below.
⇒ uPD7220 uPD7220, uPD72020 uPD72020.
Some older games skipped drawing pixels every second line,
resulting in stark scanlines. Enabling this setting stretches
every second line to the next row, masking the scanlines. Do
note that game designers would have designed their
graphics with scanlines in mind, as the PC itself came with
REMOVE SCANLINES the monitor (and thus, was the standard). It is preferable to
global.np2kai_skipline turn off scanlines here and instead simulate softer scanlines
using RetroArch's shaders for a better effect. Action-oriented
games (sprites that can move up and down) are typically fine
with no scanlines whatsoever. Later games would render in
higher resolutions, resulting in no scanlines.
⇒ Full 255 lines Full 255 lines, Off False, On True.
REAL PALETTES Some games rely on this (Apros).
global.np2kai_realpal ⇒ Off False, On True.

https://wiki.batocera.org/ Printed on 2023/08/06 23:37

2023/08/06 23:37 5/7 NEC PC-9800

ES setting name
Description ⇒ ES option key_value
batocera.conf_key
26K for old games and 86K for newer games.
⇒ None None, PC9801-14 PC9801-14, PC9801-26K
PC9801-26K, PC9801-26K + 86 PC9801-26K + 86,
PC9801-86 PC9801-86, PC9801-86 + 118(B460)
PC9801-86 + 118(B460), PC9801-86 + 118(B460) +
Sound Blaster 16 PC9801-86 + 118(B460) + Sound
Blaster 16, PC9801-86 + Mate-X PCM(B460) PC9801-86
+ Mate-X PCM(B460), PC9801-86 + Mate-X PCM(B460) +
Sound Blaster 16 PC9801-86 + Mate-X PCM(B460) +
Sound Blaster 16, PC9801-86 + Chibi-oto PC9801-86 +
Chibi-oto, PC9801-86 + Speek Board PC9801-86 +
SOUND BOARD Speak Board, PC9801-86 + Sound Blaster 16 PC9801-86
global.np2kai_SNDboard + Sound Blaster 16, PC9801-118 PC9801-118,
PC9801-118 + Sound Blaster 16 PC9801-118 + Sound
Blaster 16, AMD-98 AMD-98, Chibi-oto Chibi-oto, Sound
Blaster 16 Sound Blaster 16, Speak Board Speak
Board, Spark Board Spark Board, Sound Orchestra Sound
Orchestra, Sound Orchestra-V Sound Orchestra-V,
Little Orchestra L Little Orchestra L, Multimedia
Orchestra Multimedia Orchestra, Mate-X PCM(B460)
Mate-X PCM, Mate-X PCM + Sound Blaster 16 Mate-X PCM
+ Sound Blaster 16, Otomi-chanx2 Otomi-chanx2,
Otomi-chanx2 + 86 Otomi-chanx2 + 86, WaveStar
WaveStar.
JAST SOUND To have music and not only sound in games (Owl-Zoo).
global.np2kai_jast_snd ⇒ Off False, On True.
Emulate a keyboard/mouse/joypad.
⇒ Off False, Mouse Mouse, Arrows Arrows, Arrows 3button
JOY2KEY PROFILE
Arrows 3button, Keypad Keypad, Keypad 3button
global.np2kai_joymode
Keypad 3button, Manual keyboard Manual Keyboard,
Atari Joypad Atari Joypad.

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.

GDC clock

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.

Todo: screenshots.

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.

Batocera.linux - Wiki - https://wiki.batocera.org/

Last update: 2021/12/20 12:45 systems:pc98 https://wiki.batocera.org/systems:pc98

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.

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.

Controls

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.

Troubleshooting

My game isn't auto-booting and all I see is a command prompt

Most games should handle this automatically, but some may need to be launched manually after
https://wiki.batocera.org/ Printed on 2023/08/06 23:37
2023/08/06 23:37 7/7 NEC PC-9800

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.

My video framerate is full speed, but really choppy/inconsistent

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.

I messed up my BIOS settings and need to reset them!

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.

My games are in Japanese!

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.

Further troubleshooting

For further troubleshooting, refer to the generic support pages.

From:
https://wiki.batocera.org/ - Batocera.linux - Wiki

Permanent link:
https://wiki.batocera.org/systems:pc98

Last update: 2021/12/20 12:45

Batocera.linux - Wiki - https://wiki.batocera.org/