Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!usenet.ins.cwru.edu!tut.cis.ohio-state.edu!ucbvax!VTVM1.CC.VT.EDU!VALDIS From: VALDIS@VTVM1.CC.VT.EDU (Valdis Kletnieks) Newsgroups: comp.lang.asm370 Subject: Re: disabling CTRL-BREAK (dos) Message-ID: <9105250259.AA11782@ucbvax.Berkeley.EDU> Date: 25 May 91 02:44:42 GMT Sender: daemon@ucbvax.BERKELEY.EDU Reply-To: IBM 370 Assembly Programming Discussion List Distribution: inet Organization: The Internet Lines: 34 On Fri, 24 May 91 23:29:16 GMT Wrong newsgroup. IBM mainframes are not PC's (we wish). Phil: Why would you wish that IBM mainframes were the brain-dead architecture that the PC uses? You need the '386 before you can truly multitask safely, and even if a 386 *can* go at 15MIPS, it's still useless because it spends 12 of them doing loads and stores out of the 4 registers... At the risk of starting a holy war, MS-DOS and the Intel 8x86 architecture are the single worst thing to happen to computing. Obligatory assembler question: On small machines and handhelds (6502, HP-11, stuff like that), there's a subculture involved in exploring undocumented opcodes, "synthetic programming", and the like. Does anybody out there have a war story of a "undocumented" opcode or similar feature on an IBM 360/370/etc mainframe? My personal favorite was when I was doing MUSIC hacking, and a kernel routine of mine took a branch to East Fishkill on an IBM 4341, hit a data area, and tried to execute a SIGP instruction. Oddly enough, it died on a privop exception, not the regular operation exception you'd expect. I never got brave enough to explore whether the 4341 *really* had a SIGP instruction, or whether CP's instruction simulation was doing something to me.... And is it true that a 360/44 had its SS format instructions intentionally removed to cripple it and keep it slower than the 360/50, because the 44's floating point made it so much faster? /Valdis