Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA Path: utzoo!linus!philabs!cmcl2!seismo!brl-tgr!gwyn From: gwyn@brl-tgr.ARPA (Doug Gwyn ) Newsgroups: net.unix-wizards Subject: Re: Question, How portable are "off the shelf" unix applications? Message-ID: <5614@brl-tgr.ARPA> Date: Mon, 5-Nov-84 11:39:02 EST Article-I.D.: brl-tgr.5614 Posted: Mon Nov 5 11:39:02 1984 Date-Received: Wed, 7-Nov-84 00:59:34 EST References: <1213@eosp1.UUCP> Organization: Ballistic Research Lab Lines: 40 > 1. On the average, with 1 programmer of 2 years UNIX and C experience how > long will it take to port an 'off the shelf' UNIX business package? If > you have a justification for your statement I'd be interested. There is an excellent article in the November 1984 UNIX/WORLD (Vol 1 No 6, pp. 44-49) describing one business software house's experience in this. They changed from using IBM business systems to UNIX-based ones and improved their situation tremendously. My estimate is that porting a major package like a spreadsheet from one UNIX to ANY other UNIX implementation should take such a programmer no more than a few weeks. Sometimes it takes only hours, if the software is well-written and if the UNIXes are similar versions (e.g. both UNIX System V). > 2. What factors must I consider if I want to buy an 'off the self' application > and be sure I'll minimize (whatever minimization is) my porting efforts? This is hard to answer in a few words. Basically, stick to portable C and separate system-dependent functions out into carefully-chosen modules. Use libcurses for video screen manipulation. Avoid things that may not be supported on other target systems (e.g., shared memory, sockets, database managers, etc.); if you need these facilities, provide your own or be prepared to limit your porting to systems that provide them. As UNIX System V spreads more widely, it would make sense to expect its facilities to be there. If you're buying an "off the shelf" application, why would you be doing the porting work? > 3. What do you think of the statement "I can port any UNIX application in > 2 weeks"? Change that to "most applications" and I could believe it. > 4. What do you think of the statement "Porting any UNIX application will > take at least a man year of effort"? Porting any application that makes significant use of UNIX facilities to an obsolete OS could easily take a man-year. Porting from one UNIX to another is pretty easy; an application could probably be totally rewritten in less than a man-year!