VOGONS

A DOS gaming operating system for old and new machines.

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Reply 40 of 56, by gsos

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LSS10999 wrote on 2026-08-20, 08:50:

I'd like to see more useful screenshots as well as prebuilt release binaries/images in the future. Currently I'm looking at how to set up a proper build environment to experiment with it.

My targets would be mostly baremetal hardware, preferably installed on hard disk though I'd be doing initial tests using bootable USB sticks. Regarding emulated (not natively present) functionalities (video, sound, etc.) I wonder where I should look at in order to configure them?

And regarding the license, it's not recognized by GitHub (showing it as just "License"), but it appears to be WTFPL with the "NO WARRANTY" disclaimer taken from MIT added under it.

Yes I should invest some time into setting up a convenient flow. Building should be easy, the ./run.sh script should work basically out of the box (downloading bazelisk automatic). bazel-out/kernel.elf is the kernel, but you need a ext4 filesystem present.

The way I have it, I have linux running on my laptop. I build kernel.elf and copy it into /boot/retroos and add grub menu for it and /home/retroos is prepared to have BOOT/... (command.com, dn, config.sys) ULTRASND/ for midi patches, CD/ and FLOPPY/ contain any images (iso,cue, img) and then my games, borlandc etc..

So /home/retroos

drwxrwsr-x 3 priv-gerben retroos 4096 Aug 19 21:09 BOOT
lrwxrwxrwx 1 priv-gerben retroos   59 Aug 19 21:09 BORLANDC -> /home/priv-gerben/project/RetroOS/apps-proprietary/BORLANDC
lrwxrwxrwx 1 priv-gerben retroos   53 Aug 19 21:09 BP -> /home/priv-gerben/project/RetroOS/apps-proprietary/BP
lrwxrwxrwx 1 priv-gerben retroos   53 Aug 14 20:01 CD -> /home/priv-gerben/project/RetroOS/apps-proprietary/CD
lrwxrwxrwx 1 priv-gerben retroos   57 Aug 14 20:01 FLOPPY -> /home/priv-gerben/project/RetroOS/apps-proprietary/FLOPPY
drwxrwsr-x 2 priv-gerben retroos 4096 Aug 19 21:09 GAMES
drwxrwsr-x 4 priv-gerben retroos 4096 Aug 19 21:04 OS2
lrwxrwxrwx 1 priv-gerben retroos   47 Aug 19 21:09 ULTRASND -> /home/priv-gerben/project/RetroOS/apps/ultrasnd
drwxrwsr-x 4 priv-gerben retroos 4096 Aug 19 21:56 WINDOWS

I added initial OS2/WINDOWS support last evening, that's why those directories are there.

Then /home/retroos/BOOT

drwxrwsr-x 3 priv-gerben retroos   4096 Aug 19 21:09 .
drwxrwsr-x 8 priv-gerben retroos   4096 Aug 19 21:56 ..
-r-xrwxr-x 1 priv-gerben retroos  24144 Aug 19 21:09 COMMAND.COM
drwxrwsr-x 2 priv-gerben retroos   4096 Aug 19 21:09 DN
-r-xrwxr-x 1 priv-gerben retroos 437024 Aug 19 21:09 KERNEL.SYM
-r-xrwxr-x 1 priv-gerben retroos   2861 Aug 19 21:09 LOADFIX.CFG
-r-xrwxr-x 1 priv-gerben retroos   3428 Aug 19 21:09 SHELL.ELF

My /etc/grub.d/40_custom

cat /etc/grub.d/40_custom 
#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry "RetroOS (protected disk)" {
    insmod part_gpt
    insmod ext2
    insmod multiboot
    insmod efi_gop
    set gfxmode=auto
    set gfxpayload=keep
    search --no-floppy --file /boot/retroos/kernel.elf --set=root
    multiboot /boot/retroos/kernel.elf ram-overlay
    boot
}

menuentry "RetroOS (writeable disk)" {
    insmod part_gpt
    insmod ext2
    insmod multiboot
    insmod efi_gop
    set gfxmode=auto
    set gfxpayload=keep
    search --no-floppy --file /boot/retroos/kernel.elf --set=root
    multiboot /boot/retroos/kernel.elf
    boot
}

I recommend to start with the ram-overlay which causes disk writes to only affect the ram-overlay and not modify the hard disk. Maybe @inagy can tell in detail his setup, but he is booting from his raspberry pi.

Reply 41 of 56, by LSS10999

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Tried building but not successful. I'm using the commands you mentioned in the "Build" section of README.md instead of the run.sh which I suppose is more for running compiled targets...

My host is Arch Linux based. Currently I'm using rustup and bazelisk packages from pacman.

Here's the build output with "--verbose_failures" added to bazelisk arguments regarding the error.

INFO: Analyzed target //:image (90 packages loaded, 5933 targets configured).
ERROR: /data/RetroOS/kernel/BUILD.bazel:171:12: Compiling Rust bin retroos-host (1 file) [for tool] failed: (Exit 1): process_wrapper failed: error executing Rustc command (from target //kernel:retroos-host) 
  (cd /home/user/.cache/bazel/_bazel_user/a7f4c046dc473b410a4dd4e0a0b103ef/sandbox/linux-sandbox/515/execroot/_main && \
  exec env - \
    CARGO_CFG_TARGET_ARCH=x86_64 \
    CARGO_CFG_TARGET_OS=linux \
    CARGO_CRATE_NAME=retroos_host \
    CARGO_MANIFEST_DIR='${pwd}/kernel' \
    CARGO_PKG_AUTHORS='' \
    CARGO_PKG_DESCRIPTION='' \
    CARGO_PKG_HOMEPAGE='' \
    CARGO_PKG_NAME=retroos-host \
    CARGO_PKG_VERSION=0.0.0 \
    CARGO_PKG_VERSION_MAJOR=0 \
    CARGO_PKG_VERSION_MINOR=0 \
    CARGO_PKG_VERSION_PATCH=0 \
    CARGO_PKG_VERSION_PRE='' \
    LD_LIBRARY_PATH='' \
    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin \
    REPOSITORY_NAME='' \
    ZERO_AR_DATE=1 \
  bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~/util/process_wrapper/process_wrapper --arg-file bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__libc-0.2.186/_bs.linksearchpaths --subst 'pwd=${pwd}' --subst 'exec_root=${exec_root}' --subst 'output_base=${output_base}' -- bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~rust~rust_linux_x86_64__x86_64-unknown-linux-gnu__nightly_tools/rust_toolchain/bin/rustc kernel/src/main.rs '--crate-name=retroos_host' '--crate-type=bin' '--error-format=human' '--out-dir=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/kernel' '--codegen=opt-level=3' '--codegen=debuginfo=0' '--codegen=strip=debuginfo' '--remap-path-prefix=${pwd}=.' '--remap-path-prefix=${exec_root}=.' '--remap-path-prefix=${output_base}=.' '--emit=link=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/kernel/retroos-host' '--emit=dep-info' '--color=always' '--target=x86_64-unknown-linux-gnu' -L bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~rust~rust_linux_x86_64__x86_64-unknown-linux-gnu__nightly_tools/rust_toolchain/lib/rustlib/x86_64-unknown-linux-gnu/lib '--edition=2024' '-Cembed-bitcode=no' '--codegen=linker=/usr/sbin/gcc' '--codegen=link-arg=-fuse-ld=lld' '--codegen=link-arg=-B/usr/sbin' '--codegen=link-arg=-Wl,-no-as-needed' '--codegen=link-arg=-Wl,-z,relro,-z,now' '--codegen=link-arg=-pass-exit-codes' '--codegen=link-arg=-Wl,--gc-sections' '--codegen=link-arg=-Wl,--push-state,-as-needed' '--codegen=link-arg=-lstdc++' '--codegen=link-arg=-Wl,--pop-state' '--codegen=link-arg=-Wl,--push-state,-as-needed' '--codegen=link-arg=-lm' '--codegen=link-arg=-Wl,--pop-state' '-Lnative=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/third_party/unicorn/unicorn/lib' '-Lnative=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/_main~_repo_rules~lwext4' '-lstatic=unicorn' '-Clink-arg=-lunicorn' '-lstatic=lwext4_host' '-Clink-arg=-llwext4_host' '--extern=kernel=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/kernel/libkernel-345816794.rlib' '--extern=retroos_arch_interp=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/arch-interp/libretroos_arch_interp-391651502.rlib' '--extern=lib=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/lib/liblib-386233736.rlib' '--extern=vga=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/lib/libvga-505772366.rlib' '--extern=sound=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/lib/libsound-542287918.rlib' '--extern=lwext4=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/third_party/lwext4/liblwext4-861921465.rlib' '--extern=lwext4_sys=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/third_party/lwext4/liblwext4_sys-731513127.rlib' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/klog' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/lib' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/_main~_repo_rules~nuked_opl3' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/third_party/lwext4' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__bytemuck_derive-1.12.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__bytemuck-1.25.2' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__cfg-if-1.0.4' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__embedded-io-0.7.1' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__zerocopy-derive-0.8.56' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-fixed-2.0.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-io-2.0.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-path-2.0.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__noalloc-0.0.1' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__zerocopy-0.8.56' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__endian-num-0.2.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-macros-2.0.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__scopeguard-1.2.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__lock_api-0.4.14' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__bitflags-2.13.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-common-2.0.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-part-2.0.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__spin-0.12.2' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/_main~_repo_rules~bitflags' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/_main~_repo_rules~log' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/arch-abi' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/third_party/voodoo' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-iso-2.0.0' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/_main~_repo_rules~fatfs' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__rustc-demangle-0.1.27' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__unicorn-engine-sys-2.1.5' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__libc-0.2.186' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__unicorn-engine-2.1.5' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/kernel' '-Ldependency=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/arch-interp' '--sysroot=bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~rust~rust_linux_x86_64__x86_64-unknown-linux-gnu__nightly_tools/rust_toolchain' '-Cpanic=abort' '-Crelocation-model=static')
# Configuration: 9750c3709d99419e4c56edd72750e9f13bcc9895c954ae6e73a969df2f902206
# Execution platform: @@platforms//host:host

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
error: linking with `/usr/sbin/gcc` failed: exit status: 1
  |
  = note:  "/usr/sbin/gcc" "-m64" "/home/user/.cache/bazel/_bazel_user/a7f4c046dc473b410a4dd4e0a0b103ef/sandbox/linux-sandbox/515/execroot/_main/bazel-out/k8-opt-exec-ST-d57f47055a04/bin/kernel/rustcrQE2HF/symbols.o" "<17 object files omitted>" "-Wl,--as-needed" "-Wl,-Bstatic" "-lunicorn" "-llwext4_host" "<sysroot>/lib/rustlib/x86_64-unknown-linux-gnu/lib/libpanic_abort-*.rlib" "/home/user/.cache/bazel/_bazel_user/a7f4c046dc473b410a4dd4e0a0b103ef/execroot/_main/bazel-out/k8-opt-exec-ST-d57f47055a04/bin/kernel/libkernel-345816794.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/_main~_repo_rules~fatfs/libfatfs-1269675949.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/_main~_repo_rules~bitflags/libbitflags-2296606973.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/_main~_repo_rules~log/liblog-192684875.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/third_party/lwext4/liblwext4-861921465.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/third_party/voodoo/libvoodoo-409010663.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/third_party/lwext4/liblwext4_sys-731513127.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-iso-2.0.0/libhadris_iso-1173291256.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__bitflags-2.13.0/libbitflags-426805593.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-io-2.0.0/libhadris_io-3428972955.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__embedded-io-0.7.1/libembedded_io-400402238.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-common-2.0.0/libhadris_common-1965804352.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-path-2.0.0/libhadris_path-1453752966.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__zerocopy-0.8.56/libzerocopy-239233032.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__noalloc-0.0.1/libnoalloc-1333964645.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__hadris-fixed-2.0.0/libhadris_fixed-778759671.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__bytemuck-1.25.2/libbytemuck-3676478283.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/lib/libsound-542287918.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/_main~_repo_rules~nuked_opl3/libnuked_opl3-1202259879.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__spin-0.12.2/libspin-16997579.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__lock_api-0.4.14/liblock_api-1800404391.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__scopeguard-1.2.0/libscopeguard-2096412608.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/lib/{libvga-505772366,liblib-386233736}.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/klog/libklog-1506101342.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__rustc-demangle-0.1.27/librustc_demangle-1873733380.rlib" "/home/user/.cache/bazel/_bazel_user/a7f4c046dc473b410a4dd4e0a0b103ef/execroot/_main/bazel-out/k8-opt-exec-ST-d57f47055a04/bin/arch-interp/libretroos_arch_interp-391651502.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__libc-0.2.186/liblibc-4078536105.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__unicorn-engine-2.1.5/libunicorn_engine-323025378.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/rules_rust~~crate~crates__unicorn-engine-sys-2.1.5/libunicorn_engine_sys-616523268.rlib" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/arch-abi/libarch_abi-79344026.rlib" "<sysroot>/lib/rustlib/x86_64-unknown-linux-gnu/lib/{libstd-*,libobject-*,libmemchr-*,libaddr2line-*,libgimli-*,libcfg_if-*,librustc_demangle-*,libstd_detect-*,libhashbrown-*,librustc_std_workspace_alloc-*,libminiz_oxide-*,libadler2-*,libunwind-*,liblibc-*,librustc_std_workspace_core-*,liballoc-*,libcore-*,libcompiler_builtins-*}.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-L" "/home/user/.cache/bazel/_bazel_user/a7f4c046dc473b410a4dd4e0a0b103ef/sandbox/linux-sandbox/515/execroot/_main/bazel-out/k8-opt-exec-ST-d57f47055a04/bin/kernel/rustcrQE2HF/raw-dylibs" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-L" "<sysroot>/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-L" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/third_party/unicorn/unicorn/lib" "-L" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/_main~_repo_rules~lwext4" "-L" "<sysroot>/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "bazel-out/k8-opt-exec-ST-d57f47055a04/bin/kernel/retroos-host" "-Wl,--gc-sections" "-no-pie" "-Wl,-z,relro,-z,now" "-Wl,-O1" "-Wl,--strip-debug" "-nodefaultlibs" "-fuse-ld=lld" "-B/usr/sbin" "-Wl,-no-as-needed" "-Wl,-z,relro,-z,now" "-pass-exit-codes" "-Wl,--gc-sections" "-Wl,--push-state,-as-needed" "-lstdc++" "-Wl,--pop-state" "-Wl,--push-state,-as-needed" "-lm" "-Wl,--pop-state" "-lunicorn" "-llwext4_host"
  = note: some arguments are omitted. use `--verbose` to show all linker arguments
  = note: ld.lld: error: undefined symbol: __atomic_compare_exchange_16
          >>> referenced by cputlb.c
          >>>               cputlb.c.o:(helper_atomic_cmpxchgo_le_mmu_x86_64) in archive bazel-out/k8-opt-exec-ST-d57f47055a04/bin/third_party/unicorn/unicorn/lib/libunicorn.a
          collect2: error: ld returned 1 exit status
          

error: aborting due to 1 previous error

Target //:image failed to build
INFO: Elapsed time: 2.741s, Critical Path: 1.13s
INFO: 2 processes: 2 internal.
ERROR: Build did NOT complete successfully

BTW: Before this error I had another set of errors including this following one, which went away after adding "--repo_env=BAZEL_CONLYOPTS="-std=gnu17"" into bazelisk args according to this comment. Perhaps toolchains from Arch Linux is too new for the purpose requiring some additional efforts to make workflows compatible.

goption.c:169:14: error: two or more data types in declaration specifiers
  169 |     gboolean bool;
      |              ^~~~
goption.c:169:18: warning: declaration does not declare anything
  169 |     gboolean bool;
      |                  ^
goption.c: In function 'free_changes_list':
goption.c:1603:60: error: expected identifier before 'bool'
 1603 |               *(gboolean *)change->arg_data = change->prev.bool;

Reply 42 of 56, by gsos

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Hmm thanks for the report, maybe try "bazelisk build //:image --host_linkopt=-latomic " .

Reply 43 of 56, by LSS10999

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gsos wrote on 2026-08-20, 16:11:

Hmm thanks for the report, maybe try "bazelisk build //:image --host_linkopt=-latomic " .

Thanks. Build process went through. However, it seems there's something not right with the finalization part, ending with errors.

Regarding the error, it tried to run "tools/dosrt/interp_tcc.sh" which involves building a COMMAND.COM with... "TCC.EXE", using "retroos-host" which I think is compiled in the previous steps.

And the process was aborted (core dumped). The "run.log" (which I cannot find a physical copy of) printed on the console says:

---- run.log ---- Storage: ata0 (1312 MB) Block devices initialized Platform: host=Interp vga_passthrough=false firmware=Substit […]
Show full quote

---- run.log ----
Storage: ata0 (1312 MB)
Block devices initialized
Platform: host=Interp vga_passthrough=false firmware=Substitute audio=EmulatedSilent hostfs=true debug=HostStdout
Disk writes: PERSISTENT — pass `ram-overlay` to protect the disk
Threading initialized
ext4 root (1280 MB)

thread 'main' (10) panicked at kernel/src/kernel/startup.rs:359:23:
ext4 mount failed: ext4_mount failed
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Does this step of the build process require root privileges (sudo)? I'm currently running the command as normal user... though I'm afraid I need to be privileged to be able to mount or umount.

Reply 44 of 56, by gsos

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I attached command.com so you can just restrict to compiling kernel.elf and use command.com from attachment

Reply 45 of 56, by gsos

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Hmm maybe your new version of ext4 tools use new features, the dormant lwext4 lib i use not support. I pushed a branch claude/ext4-mkfs-feature-pinning , that has some updates around not using newer features

Reply 46 of 56, by LSS10999

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gsos wrote on 2026-08-20, 17:24:

Hmm maybe your new version of ext4 tools use new features, the dormant lwext4 lib i use not support. I pushed a branch claude/ext4-mkfs-feature-pinning , that has some updates around not using newer features

I'm not sure about the details. I checked the lwext4 library and it seems the repo on GitHub is at least 4 years old (with the official release being at least 10 years old).

So it's entirely possible that newer Linux kernels and extfs tools have enabled certain features by default, that were not supported by lwext4.

Reply 47 of 56, by gsos

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@LSS10999 i removed lwext4 its unmaintained and i had my own fork with bug fixes anyway. So I moved to a new ext4 implementation which should work with the new features.

Reply 48 of 56, by LSS10999

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gsos wrote on 2026-08-23, 17:58:

@LSS10999 i removed lwext4 its unmaintained and i had my own fork with bug fixes anyway. So I moved to a new ext4 implementation which should work with the new features.

After pulling current changes from master I'm able to finish building. Not sure if I should do a clean build but at least I get an "image.bin" artifact.

Should I flash this file as-is to a USB stick so I could boot it on actual system?

And can this be mounted directly with QEMU to boot? I'm using virt-manager (libvirt) for managing QEMU VMs, though.

Reply 49 of 56, by gsos

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yes is you can build image you can boot the image with qemu, use "./run.sh qemu x64 --firmware (uefi/bios) --sound (hda/ac97/sb) (--kvm) " to boot inside qemu.

I haven't build a usb storage driver, so it can't mount usb fs. This should definitely be my next feature.

I use my linux ext4 system, ie. copy the kernel to "/boot/retroos" (tools/install_kernel.sh) add a grub entry. And make a "/home/retroos" that is interrpreted as C: .

Make sure you use "protected disk" which ensures no writes go to ext4 by adding a ram-overlay over a readonly ext4 partition,

menuentry "RetroOS (protected disk)" {
insmod part_gpt
insmod ext2
insmod multiboot
insmod efi_gop
set gfxmode=auto
set gfxpayload=keep
search --no-floppy --file /retroos/kernel.elf --set=root
multiboot /retroos/kernel.elf ram-overlay
boot
}

Reply 50 of 56, by superfury

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gsos wrote on 2026-08-24, 15:58:
yes is you can build image you can boot the image with qemu, use "./run.sh qemu x64 --firmware (uefi/bios) --sound (hda/ac97/sb) […]
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yes is you can build image you can boot the image with qemu, use "./run.sh qemu x64 --firmware (uefi/bios) --sound (hda/ac97/sb) (--kvm) " to boot inside qemu.

I haven't build a usb storage driver, so it can't mount usb fs. This should definitely be my next feature.

I use my linux ext4 system, ie. copy the kernel to "/boot/retroos" (tools/install_kernel.sh) add a grub entry. And make a "/home/retroos" that is interrpreted as C: .

Make sure you use "protected disk" which ensures no writes go to ext4 by adding a ram-overlay over a readonly ext4 partition,

menuentry "RetroOS (protected disk)" {
insmod part_gpt
insmod ext2
insmod multiboot
insmod efi_gop
set gfxmode=auto
set gfxpayload=keep
search --no-floppy --file /retroos/kernel.elf --set=root
multiboot /retroos/kernel.elf ram-overlay
boot
}

Where can this latest version be found (repo)?

Also, does it support pre-SB16 real (or Dosbox/UniPCemu emulated) hardware (SB1.x, SB2.x, SB Pro, pure Adlib (or gold?), MPU-401, game blaster)?

Author of the UniPCemu emulator.
UniPCemu Git repository
UniPCemu for Android, Windows, PSP, Vita and Switch on itch.io

Reply 51 of 56, by gsos

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Yes, it should just be master branch on the repo. I'm currently not very good in keeping master healthy at all times, but it should work.

For hardware the model is, if it exist natively, (s)vga or sb/adlib/mpu-401, then use the hardware natively, ie. the ports are open/pass through and the games talk to hardware directly. For sb, it still traps some ports for recording so we can perfectly save and restore its state. The only thing we don't use natively is DMA as that is privileged and the paging can't guarantee contiguous and <16mb memory, so we have a virtualized DMA the games talk to that correctly re-pages the games virtual address ranges into actual contiguous low mem physical ranges.

If the hardware does not exist natively (for instance pure uefi GOP without VGA support or AC97/HDA soundcard) we fully emulate those and games don't know. For super vga modes, we do wrap the native BIOS so that we only support modes that we can fully emulate, this allows seamless switching dos-apps and presenting OSD monitor on top of playing games.

Reply 52 of 56, by gsos

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A few new features.
1) Added fat filesystem support, so you can boot with grub on a regular fat filesystem.
2) Added initial win 3.11 support (minesweeper and first inklings of castle of the winds)
3) Added primitive os/2 support (minesweeper)
4) The on-screen display is now more integrated with the windows/os2 GUI compositing. So you can play dos games in windowed mode. But all still in initial state
5) Added switching between native sound blaster and kernel mixing (emulated SB, emulated GUS, emulated OPL and emulated general midi) where sound blaster is the final output sink.

Worked on optimizing kernel, so that the OS can be used on old pc's. It still needs to much memory, probably need to add some page swapping to support 4mb units.

I added binary release artifacts for convenience https://github.com/gerben-stavenga/RetroOS/re … ses/tag/retroos . One kernel.elf + expected directories (boot/Dos Navigator + ultramid) and a image you can immediately use with qemu or 86box.

Reply 53 of 56, by LSS10999

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gsos wrote on Yesterday, 04:20:
A few new features. 1) Added fat filesystem support, so you can boot with grub on a regular fat filesystem. 2) Added initial wi […]
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A few new features.
1) Added fat filesystem support, so you can boot with grub on a regular fat filesystem.
2) Added initial win 3.11 support (minesweeper and first inklings of castle of the winds)
3) Added primitive os/2 support (minesweeper)
4) The on-screen display is now more integrated with the windows/os2 GUI compositing. So you can play dos games in windowed mode. But all still in initial state
5) Added switching between native sound blaster and kernel mixing (emulated SB, emulated GUS, emulated OPL and emulated general midi) where sound blaster is the final output sink.

Worked on optimizing kernel, so that the OS can be used on old pc's. It still needs to much memory, probably need to add some page swapping to support 4mb units.

I added binary release artifacts for convenience https://github.com/gerben-stavenga/RetroOS/re … ses/tag/retroos . One kernel.elf + expected directories (boot/Dos Navigator + ultramid) and a image you can immediately use with qemu or 86box.

I did a test with your QEMU image on my Arch Linux host (QEMU 11 via virt-manager) but no success. I wonder what should be the expected behavior.

I created a VM using Win7 profile as that would be closer to my actual HW targets, and more compatible to DOS/Windows stuffs. The image boots, but shortly after it switched to show some colored stuffs that look garbled and finally ended in a blank screen.

Using QXL or VGA for video makes no difference. Other options simply won't boot.

Reply 54 of 56, by gsos

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You used this image https://github.com/gerben-stavenga/RetroOS/re … ses/tag/retroos ?
This should then work out of the box (make sure image.bin is writable)

qemu-system-i386 -hda image.bin -device sb16 -display sdl

This produced your issues? Or did you build image from source on your arch-linux? I hoped my new ext4 filesystem driver was compliant with the latest versions, but i haven't tested it exhaustively.

Reply 55 of 56, by LSS10999

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gsos wrote on Yesterday, 13:54:
You used this image https://github.com/gerben-stavenga/RetroOS/re … ses/tag/retroos ? This should then work out of the box (mak […]
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You used this image https://github.com/gerben-stavenga/RetroOS/re … ses/tag/retroos ?
This should then work out of the box (make sure image.bin is writable)

qemu-system-i386 -hda image.bin -device sb16 -display sdl

This produced your issues? Or did you build image from source on your arch-linux? I hoped my new ext4 filesystem driver was compliant with the latest versions, but i haven't tested it exhaustively.

Yeah I used the image from the release. I normally don't run QEMU directly. I'm using virt-manager to create and launch the VMs.

Virt-manager only supports SPICE and VNC display methods and I mainly use SPICE. For Windows guests I use QXL (though VGA can also be used if needed by certain drivers). Not sure if the issue is with SPICE...

On the other hand, I did grab the kernel and data files to try on a real system, but it appears the kernel.elf is in a format that GRUB4DOS cannot recognize so I didn't test any further. Maybe I need to boot with GRUB2 from a Linux distro...

And a suggestion: Consider using a different folder than C:\BOOT (e.g. C:\RETROOS), as in a multiboot scenario with modern Windows like Vista/7, BOOTMGR is also installed in C:\BOOT (where C: is the boot partition and FAT32 is allowed in this case) so care must be taken not to mess up other stuffs in that folder or you may break booting of Windows (BOOTMGR).

UPDATE: Looks like I still have to use i440FX machine type. Q35 is not a good idea. I recreated the VM using FreeDOS 1.3 profile (which uses i440FX) and this time, while the colored, garbled output (presumably a boot logo) still shows, it correctly booted and I'm now in the DOS Navigator interface.

Reply 56 of 56, by gsos

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I renamed C:\BOOT to C:\RETROOS, which is indeed a better choice.

I also split the images: a boot image, rebuilt by Bazel, contains the kernel and runtime files such as DN and
COMMAND.COM. The runtime is exposed read-only, while a second image holds persistent data, including DN
settings and history.

RetroOS doesn’t support AHCI yet, which could explain why Q35 failed while i440FX worked. You can add a legacy
IDE controller to Q35 and attach both disks to it:

qemu-system-x86_64 \
-machine q35 \
-m 256 \
-device piix3-ide,id=legacy \
-drive file=boot.img,format=raw,if=none,id=boot \
-device ide-hd,drive=boot,bus=legacy.0,unit=0,bootindex=1 \
-drive file=data.img,format=raw,if=none,id=data \
-device ide-hd,drive=data,bus=legacy.0,unit=1

These filenames refer to the new two-image bundle, not the older image.bin release.

I’m still unsure what causes the garbled screen; RetroOS doesn’t display a graphical boot logo.

I also tested GRUB4DOS 0.4.6a (2020-08-09) in QEMU with the published kernel and image, and it booted into DN.
I used kernel /kernel.elf ram-overlay, followed by boot. Which GRUB4DOS version and command did you use, and
what was the exact error?

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