Hi! I started with scr and failed with "ring", getting these results: PAD ring router Alliance CAD System 4.5.0, ring 2.11 Copyright (c) 1991-2002, ASIM/LIP6/UPMC E-mail support: alliance-support@asim.lip6.fr o reading netlists, layout views of core and pads. Warning 2 : consistency checks will be disabled o reading file of parameters, including the placements of pads. o making equipotential list. o making the first placement of pads. o filling data internal structures. o reading the connectors positions of the core. Distance between connector <i 8> and connector <i 7> of the core isn't big enough. make: *** [chip.ap] Error 20 So, I replaced the "scr" command in the Makefile with "ocp" and "ocr". I.e., heart.ap : heartp.ap ... $(SCR) -p -r heart;\ changed to: heart.ap : asimut_vst heartp.ap ... $(OCR) -v -L heart -P heartp -O heart heartp.ap : asimut_vst ... $(OCP) -v heart heartp I also added a memory usage info message to "mbk/mbk_sys.c", which shows something's gone terribly wrong with both Cygwin and Linux running out of memory. Linux just kills the process when memory exhausts from the malloc() call. Windows, exits the process gracefully, I.e., Now: Debug1: i_pDataBase='heartp', i=595 o It = 826 Sig = 584 Failures : 26 o Ordering : Priority, Connectors ... Debug2: Count: 504000, i=140 *** mbk error *** fatal mbkalloc error : not enough memory info: 44 KB requested. 2380285 KB allocated Signal 11 make: *** [heart.ap] Error 139 I added the "Debug" messages for debugging and note the memory seems to exhaust when 2.4 GB have been allocated. I noticed ocr under Linux would iterated about 529 times with "Failures" down to 12. Ocr under Cygwin went further, but still exhausted memory as shown above. What can I do to troubleshoot and continue this tutorial? I ran graal on the output from scr and ocp. I can send any files via a zip archive attachment, if anyone is interested. Admittedly, I'm naive about layout, but I observed ocp generated a smaller files vs scr, presumably due to the lack of routing in the ocp output, which ocr was suppose to do. I'll append the context diff of mbk_sys.c and ocrRouter.c in the next message to alliance-programmer mail list. Thanks & Regards, Art