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Project Norebo

Norebo is a hack to run some Project Oberon 2013 software on the Unix command line. Programs that use the GUI obviously won't work, but e.g. the compiler runs.

I probably won't be maintaining this project, so feel free to fork if you want to develop it further.


  • Runtime/ RISC5 emulator and operating system interface.
  • Oberon/ Unmodified source code from Project Oberon 2013.
  • Norebo/ Norebo-specific and new modules.
  • Bootstrap/ Pre-compiled modules to bootstrap Norebo.
  • Script to rebuild Norebo. See Norebo in action.

PO2013 image build tools

This repository also contains tools to build fresh PO2013 filesystem images. Use it like so:

./ upstream
./ upstream

...where upstream is the name of the directory where the sources should live. (Replace it with the name of your choice.) This will download the project sources, compile them, create runnable disk image build/Oberon.dsk. The CSV build manifest controls which set of files should define the resulting system. The disk image can be run on the Project Oberon RISC emulator.

Supporting Oberon modules are stored in Norebo: a virtual file system (VDiskUtil/VFile) and a static linker for the Inner Core. All this is based on code from PO2013.

File handling

New files are always created in the current directory. Old files are first looked up in the current directory and if they are not found, they are searched for in the path defined by the OBERON_PATH environment variable. Files found via OBERON_PATH are always opened read-only.


Probably many.

Files are not integrated with the garbage collector. If you don't close a file, it will remain open until Norebo exits.

Most runtime errors do not print a diagnostic message. Here's a table of exit codes:

Exit code Meaning
  1..7 | possibly a Modules error
     5 | (also) unknown command
   101 | array index out of range
   102 | type guard failure
   103 | array or string copy overflow
   104 | access via NIL pointer
   105 | illegal procedure call
   106 | integer division by zero
   107 | assertion violated


Project Norebo




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