Bob,

> Could you say a word about images to be used with j3?

The only "out-of-the-box" image that will work correctly is the one
that is supplied with the j3 release.

> What sort of problems might one encounter using anything other than
> the j3 image you refer to?

There are several change sets in the j3 image directory that make
various parts of an image compatible with j3:

  CCodeGen, Interpreter and Support
    are required to rebuild from source, and are relative to a "vanilla"
    2.8 image.  If generating a working interp.c is not an issue, then
    these can be ignored.

    They include:
      - modifications to the "preserved method list" (funtions that
        are kept even if inlined into all callers);
      - a new set of runtime compiler hooks in the Interpreter;
      - modifications to the support code for generating the primitive
        table.

  Contexts and Exceptions
    are *required* to run.  Contexts should be compatible with just
    about any image, and Exceptions with images starting somewhere in
    middle of the 2.7 update stream -- although the safest way to pull
    this into a non-2.8 image is to browse the change set code, and
    then just fiddle with things until the ExceptionTester can
    runAllTests correctly.

    These include:
      - resetting the "receiverMap" field to nil whenever certain
        changes are made to the state of a MethodContext;
      - fixes to the exceptions to make them work with reentrant
        ("copy on value") block activation.

I know that's relatively little info, but I hope it helps.

Regards,

Ian