http://bauxite.sakura.ne.jp/software/dos/freedos.htm#fdkernel
https://github.com/lpproj/fdkernel
(branch: nec98test)

This is a fork of FreeDOS development kernel, intended to handle correctly double-byte character set (DBCS) like Japanese:

• handle DBCS pathname on file manipulation (create, open, find, rename and so on)
• handle DBCS characters on input/output for character devices (not implemented yet)
• DBCS-awared NLS functions: upcase, downcase and collating

All tasks are working-in-progress and unstable (experimental).

Now FreeDOS DBCS kernel also supports not only IBM PC (compatibles) but NEC PC-9801/9821 series (and compatibles made by EPSON). The portion was based on tori's work (Another FreeDOS(98), and I (lpproj) add a little improvements:

• sync with latest fdkernel
• supports both FD (2DD/2HD/1.44M) and HD (SASI/SCSI)
• supports various sizes of sector (256 and 512 bytes for physical, up to 2048 bytes for logical)
• handle DBCS pathname
• improve compatibility with genuine (NEC) MS-DOS

Needless to say, this port is an experimental.

You can build FreeDOS DBCS kernel (ibmpc or nec98) on Windows (x86/x64) or Linux (i*86/amd64).

• OpenWatcom C/C++ (other compilers are not supported)
• nasm
• upx : The official build is recommended ("open-source" edition has less performance for compression than the official)
• GNU make (mingw32-make.exe, on Windows)

build step for FreeDOS for PC-9801/9821:

1. cd nec98 (When you want to build for IBM PC, type cd ibmpc)
2. copy config.m config.mak (on Linux, cp config.m config.mak)
3. Edit config.mak for your configuration.
4. mingw32-make clobber (on Linux, make clobber)
5. mingw32-make all (on Linux, make all)

When you don't need DBCS featues, you should modify platform.mak and remove -DDBCS