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The NEC PC-9800 series are 16/32-bit computers from NEC Corporation. It marked a shift away from the Z80-based PC-88 to the x86 architecture. Just like their predecessor series, they were known for their unique sound hardware by YAMAHA, and games kept the systems popular. They were likely never released outside Japan in the series lifespan, except for the APC III.


ReactOS PC-98 port is under slow development.

Help in testing

You can run ReactOS only on i586 class CPUs and above, so that means you can run it on any of the models with a Pentium CPU. Keep in mind ReactOS requires at least 64 MB of RAM. It's recommended to use NEC PC-9821Ra43 with a Celeron CPU @ 433 MHz which is the last model in the series. Currently ReactOS only supports booting from a 1.44 MB 3.5" internal floppy drive. After booting up using the diskette, FreeLoader loads a boot image from any of supported devices: IDE CD-ROM, SCSI CD-ROM or MO.

You need the following steps:

  • Check out this article to learn more about the testing process.
  • You should be able to compile ReactOS.
  • Run the following command configure -DSARCH=pc98 before compilation to set target platform as PC-98.
  • Execute ninja pc98bootfdd build target to create a bootable floppy image. The created image will be placed on /output folder/PC98/.
  • Build and burn a LiveCD/BootCD ISO image.
  • Insert the floppy disk, medium, and boot ReactOS.

Any test results will be useful to improve PC-98 port.


The PC-9800 series use a custom hardware C-bus (later models do use PCI) and a firmware that is completely different from a Standard PC BIOS, so a new HAL should be created.

In Windows 2000 there are four known HALs for this platform:

File Name Hardware ID String HAL Name
hal98up.dll nec98Notmr_up PC-9800 System Clock 10MHz
hal98tmr.dll nec98tmr_up PC-9800 System Clock 10MHz (support 2nd Timer)
hal98apc.dll nec98mps_up NEC PC-9800 APIC HAL
hal98mp.dll nec98mps_mp NEC PC-9800 MPS HAL

PC-9800 series hard disks are usually formatted with FAT12, but they use 1024 bytes per sector as opposed to the PC's 512.

Some known chipsets used on the Pentium and later PC-98s are: Intel 430FX Intel 430HX Intel 430VX Intel 430TX Intel 450KX Intel 440FX VLSI Wildcat (SuperCore 594)

Some known video adapters used in PC-98 are: Trident Microsystems TGUI 9660/938x/968x Cirrus Logic CL-GD5430 and CL-GD5446


  • Neko Project 21/W is a NEC PC-9821 series emulator that can run Windows 2000. It potentially can be used for ReactOS PC-98 port development and testing.
  • SL9821 is a NEC PC-9821 series emulator with partial compatibility with Windows 2000 (no sound, no network, IDE issues). ROM image files are required to run SL9821.
  • QEMU/9821 also exists, but it seems not maintained anymore and does not run Windows 2000.
  • DOSBox-X and MAME can emulate a wide range of PC-98 hardware.

See Also

ReactOS ports‎
In active development Intel IA-32 (x86) | AMD64 (x64)
In slow development NEC PC-98 (x86) | Xbox (x86)
Unmaintained ARM32 (armv7) | PowerPC (ppc) | OLPC (x86)
Missing ports that Windows has ARM64 (aarch64) | Intel IA-64 (Itanium) | SGI 320/540 (x86) | DEC Alpha (axp) | MIPS