Re: [T. V. Raman] read-only modes should be using buffer-disable-undo?

[Richard Stallman]

    I wasn't refering to the optimization with respect to grouping small
    chunks of output; rather, I was indicating that perhaps we could avoid
    having undo information altogether in read-only modes like man-mode.

Certainly.  If you know of any such modes that need this change,
please just say which, or else write and contribute patches.

    Further, for modes like shell-mode, it would be nice to give the
    end-user to disable the collection of undo information in modes like
    shell/comint mode; e.g. before launching a large compile.

The entire output from the compiler ought to make one small undo
entry.  There is already code to do this, to combine the various
consecutive insertion entries into a single insertion entry.

Does this actually fail for you?  If so, can you send a test case?