Linux/PC-98 v0.2.0

Linux/PC-98 v0.2.0

This release provides three bootable PC-98 disk images:

• linux-7.1-pc98-i486-busybox.img.xz — Linux 7.1 with a static
  i486 musl/BusyBox userland.
• linux-7.1-pc98-i686-busybox.img.xz — Linux 7.1 with a static
  i686 musl/BusyBox userland.
• debian13-pc98-i686-live-cfcard.img.xz — Linux 6.12 with a
  Debian 13 i686 userland, suitable for QEMU or writing to a CF card.

This release now also includes an experimental true-i386 image for the
screen-and-keyboard console.

Highlights

• Adds reproducible Linux 7.1 BusyBox image targets for both i486 and i686.
• Fixes repeated keyboard input on physical PC-98 hardware.
• Retains the PC-98 IPL and FAT16 Linux loader used by the previous release.
• Includes the e100 driver for the Intel PRO/100 adapter found in the
  PC-9821 Ra43.
• Preserves the requested CF-card filename after extraction:
  debian13-pc98-i686-live-cfcard.img.

Requirements

These images require the PC-98-enabled
qemu-pc98 build. Upstream QEMU
does not provide the required PC-98 machine and devices.

Use an i486 guest CPU for the i486 BusyBox image:

qemu-system-i386 \
  -M pc9821 \
  -cpu 486 \
  -m 64 \
  -accel tcg \
  -drive if=ide,bus=0,unit=0,format=raw,file=linux-7.1-pc98-i486-busybox.img

Use at least a Pentium II CPU for either i686 image:

qemu-system-i386 \
  -M pc9821 \
  -cpu pentium2,-apic \
  -m 128 \
  -accel tcg \
  -drive if=ide,bus=0,unit=0,format=raw,file=debian13-pc98-i686-live-cfcard.img

The initial root password for the Debian 13 image is pc98. The BusyBox
images start an interactive root shell without a password.

Verification

Each image was tested under qemu-pc98 with TCG. The expected kernel booted,
mounted the NEC98-partitioned ext4 root filesystem, and invoked
/sbin/init. The Linux 7.1/i486 image has also booted on a physical
PC-9821 Ra43.

Verify an archive before extraction:

sha256sum -c linux-7.1-pc98-i486-busybox.img.xz.sha256
xz -dk linux-7.1-pc98-i486-busybox.img.xz

The corresponding .sha256 file is provided for every archive.

Writing the Debian image to a CF card

After carefully identifying the target device, write the decompressed image
to the whole CF card rather than to an existing partition:

xz -dc debian13-pc98-i686-live-cfcard.img.xz |
  sudo dd of=/dev/sdX bs=4M status=progress conv=fsync

Replace /dev/sdX with the correct CF-card device. This operation overwrites
the selected device.

Experimental i386 video-console image

• linux-7.1-pc98-i386-video-console.img.xz — Linux 7.1 with a static
  i386 musl/BusyBox userland for 80386-class PC-98 systems.
• Uses the GDC text screen and PC-98 keyboard only; the serial driver and
  serial console are disabled to reduce the kernel and runtime footprint.
• Displays Please press Enter to activate this console. before opening
  the root shell.
• Tested with qemu-pc98 at both 8 MiB and 4,736 KiB of guest RAM.

Use the latest qemu-pc98 executable and matching compatibility BIOS files:

qemu-system-i386 \
  -M pc9801 \
  -cpu 386 \
  -m 8M \
  -accel tcg \
  -L /path/to/qemu-pc98/pc-bios \
  -drive if=ide,bus=0,unit=0,format=raw,file=linux-7.1-pc98-i386-video-console.img \
  -serial none