Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!newsfeed101.telia.com!starscream.dk.telia.net!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: "Paul E. Bennett" Newsgroups: comp.lang.forth Subject: Re: Function Points Followup-To: comp.lang.forth Date: Mon, 27 Aug 2012 15:52:44 +0100 Organization: Hidecs Consultancy Lines: 61 Message-ID: References: <2bebf6e6-dab7-4134-904f-a57e90765fd3@googlegroups.com> <8545a450-d245-46ea-93cf-0b34a7bdbf8d@googlegroups.com> <2012Aug23.165054@mips.complang.tuwien.ac.at> <7x8vd5jvoh.fsf@ruckus.brouhaha.com> <2012Aug25.161317@mips.complang.tuwien.ac.at> <7x8vd299q5.fsf@ruckus.brouhaha.com> <503929e3$0$283$14726298@news.sunsite.dk> <7xfw7aipyk.fsf@ruckus.brouhaha.com> <86b6066f-415d-4632-a8d3-3fbc28ab01ba@n9g2000yqn.googlegroups.com> Reply-To: Paul_E.Bennett@topmail.co.uk Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7Bit X-Trace: individual.net 9HlrL4LksV7t+JyoFj9dxQROmDfxAUktxotOmHcLG+XcoH6lkter7dWMwN0QtAExe3 Cancel-Lock: sha1:+N6u7QyYO502nwrCbWaeKckwaSE= Mail-Copies-To: Paul_E.Bennett@topmail.co.uk User-Agent: KNode/0.99.01 Xref: csiph.com comp.lang.forth:15193 Mark Wills wrote: [%X] >> Writing a whole page of code at a time just has the wrong feel to doing >> the job right. Concentrate on the correctness of one function at a time, >> review the intent (as expressed in the glossary text you wrote to specify >> what was to happen) and test each word as you complete it (ensuring it >> meets the specification of the glossary). On this basis I built the >> techniques for certification of Forth code to ensure compliance with >> specification. No real hunting required for the hidden bugs as you should >> expunge them as you go to ensure they are not introduced in the first >> place. Of course, you need to really concentrate on getting the >> specification right first. > Agreed. And you also have to accept that you can't get your > documentation 100% perfect up-front. It's just a fact of life that > you'll discover something during the physical implementation that may > require you to add a new function (perhaps to handle an unanticipated > exception, for example) that will require you to re-vist and update > your documentation. This is so true too. I estimate that you will probably visit each part of the system 3 times during development (especially working on critical systems). > It's not Necessarily a design failure. It's just reality! > > We spend weeks working on up-front software documentation. Working in > the mission-critical oil and gas business, it's just a normal part of > the design process. Do you have a good grasp of the total concept at that time or is the specification still a collection of "I would like" type items? I have seen many organisations that do the up-front documentation on half baked design specs that still have lots of un-answered questions. The trick is usually to be a lot clearer about the full explicit requirements that will mean mission success early enough, even if all the fine details haven't yet emerged. This may take a number of review sessions that truly walk the problem space before the design really begins. > We're pretty good at it (we can design to SIL-1 on > our in-house designed and manufactured controllers) but we still come > across issues that we failed to anticipate, despite numerous peer > reviews and design reviews! They're never show-stoppers, but there's > always a gotcha lurking in there somewhere! There is no reason why you shouldn't deal with SIL-3 or SIL-4 requirements if you are able to improve your early design and development processes. Eliminate the systematic bugs before they get into the system design and you save a lot of time, effort and money in the later stages. -- ******************************************************************** Paul E. Bennett............... Forth based HIDECS Consultancy Mob: +44 (0)7811-639972 Tel: +44 (0)1235-510979 Going Forth Safely ..... EBA. www.electric-boat-association.org.uk.. ********************************************************************