It works. Thanks for the answer. Speaking of *inferior-lisp*, there is one more thing. AServe can be told to enter the debugger when a worker thread encounters an error. In this case under CMUCL the debugger appears in the *inferior-lisp* buffer. (Under sbcl-mt it is nowhere to be found, but it is probably due to this and not SLIME related: debugger invoked on a SB-INT:SIMPLE-CONTROL-ERROR in thread 5669: attempt to RETURN-FROM a block or GO to a tag that no longer exists ) OK, *one* more thing: (defun long-running-printer () (dotimes (i 3) (prin1 i) (force-output) (sleep 2))) Now, lets wait for '1', type 't', wait for '2' to appear and then press enter: CL-USER> (long-running-printer) 01t2<enter> Error: the variable T2 is unbound. If one presses enter only after the prompt appears then: CL-USER> (long-running-printer) 0t12 NIL CL-USER> ; No value which isn't very good either. Gabor