Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!ucsd!sdcc6!mplvax!cdl From: cdl@mplvax.EDU (Carl Lowenstein) Newsgroups: comp.sys.apple Subject: Re: multitasking, softswitch, etc. Message-ID: <841@mplvax.EDU> Date: 30 Mar 89 16:23:09 GMT References: <8903181259.aa27052@SMOKE.BRL.MIL> <10183@bloom-beacon.MIT.EDU> Reply-To: cdl@mplvax.ucsd.edu.UUCP (Carl Lowenstein) Organization: U.C. San Diego, Marine Physical Laboratory Lines: 17 In article jac@paul.rutgers.edu (J. A. Chandross) writes: >An Apple with a RocketChip (plug, plug) or a Zip Chip, or a Transwarp, etc >is a kick-ass machine compared to the early PDP-11's. The early 11's took >tens of microseconds to add 2 sixteen bit numbers, and yet could still run >a *real* operating system with *multitasking*. Not really pertinent to comp.sys.apple, but the early PDP-11's weren't quite that slow. 2.6 microseconds for a 2-operand register-to-register instructions, 1.5 for 1-operand. Plus memory access time if needed, about 1.1 microseconds for each. This is the 11/20 I am referring to. Some of the cheaper microprogrammed versions that came out after that were slower. -- carl lowenstein marine physical lab u.c. san diego {decvax|ucbvax} !ucsd!mplvax!cdl cdl@mplvax.ucsd.edu