Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!udel!haven.umd.edu!mimsy!jogger.cs.umd.edu!straub From: straub@jogger.cs.umd.edu (Pablo A. Straub) Newsgroups: comp.software-eng Subject: Re: Provocative statement Message-ID: <34081@mimsy.umd.edu> Date: 6 May 91 18:53:30 GMT References: <9776@castle.ed.ac.uk> <1991Apr25.133216.20855@jyu.fi> <1991May3.195844.25823@dg-rtp.dg.com> Sender: news@mimsy.umd.edu Reply-To: straub@cs.umd.edu (Pablo A. Straub) Organization: U. of Maryland, Dept. of Computer Science, College Park, MD 20742 Lines: 22 In article <1991May3.195844.25823@dg-rtp.dg.com> cole@farmhand.rtp.dg.com (Bill Cole) writes: |>Jim Showalter writes: |> >If the bridge designer wants to have a greater security factor, |> >(s)he can specify a little thicker steel and cables than suggested |> >by standard calculations. The software designer cannot say: "This |> >system has to be really safe and secure, so let's put in 30% more |> >code!" |> |> I disagree strongly with this. It has been my experience that the |> systems that are engineered from the outset to have excellent error |> detection and correction mechanisms are quite robust and |> fault-tolerant. Often, the amount of error code that is involved CAN |> be about 30% of the total. Yes, you can engineer software robustness. But let's not stretch the analogy to far. Software is still not continuous and robustness is not achieved by adding more of the same. As Jim Showalter explained to us, program robustness is achieved by changing the design, not just adding more code. Pablo Straub