Sirs, I was researching about old binary formats and did some tests. Meantime, I was able to run sucessfully only the QMAGIC format. Nonetheless, the OMAGIC, NMAGIC and ZMAGIC didn't work anymore. The test occurred using old slackware binaries and some new, the latter compiled by me, using cross-compiled as and ld. In any case, the QMAGIC was the only functional. After some debugging I identified (when loading a OMAGIC) that the kernel sigkill the current after this checking: http://lxr.linux.no/linux+v3.13.5/arch/x86/ia32/ia32_aout.c#L325 325 error = vm_brk(text_addr & PAGE_MASK, map_size); 326 327 if (error != (text_addr & PAGE_MASK)) { 328 send_sig(SIGKILL, current, 0); 329 return error; 330 } I suppose this happens due to changes made, in the course of time, in the memory mapping (vm_brk/do_brk), therefore the only one that still works is the QMAGIC (the aligned one). Or maybe, it's purposely. [RFC] Is important to note that when a ZMAGIC is loaded what happens is a "Segmentation fault" and not "SIGKILL". That was reported by others too: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/966472 -- Regards, Geyslan G. Bem hackingbits.com