Date: Tue, 28 Feb 2012 12:47:28 +0000 From: Anton Shterenlikht <mexas@bristol.ac.uk> To: Jerome Herman <jherman@dichotomia.fr> Cc: freebsd-questions@freebsd.org Subject: Re: posix compliance Message-ID: <20120228124728.GA57348@mech-cluster241.men.bris.ac.uk> In-Reply-To: <4F4CC8D1.4070000@dichotomia.fr> References: <20120228091746.GA48977@mech-cluster241.men.bris.ac.uk> <4F4CB09B.7010806@herveybayaustralia.com.au> <20120228110323.GA56536@mech-cluster241.men.bris.ac.uk> <20120228062537.31ac74c0@scorpio> <20120228113213.GA56638@mech-cluster241.men.bris.ac.uk> <4F4CC8D1.4070000@dichotomia.fr>
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On Tue, Feb 28, 2012 at 01:30:09PM +0100, Jerome Herman wrote: > On 28/02/2012 12:32, Anton Shterenlikht wrote: > >On Tue, Feb 28, 2012 at 06:25:37AM -0500, Jerry wrote: > >>On Tue, 28 Feb 2012 11:03:23 +0000 > >>Anton Shterenlikht articulated: > >> > >>>On Tue, Feb 28, 2012 at 08:46:51PM +1000, Da Rock wrote: > >>>>On 02/28/12 19:17, Anton Shterenlikht wrote: > >>>>>I'm putting together a small presentation > >>>>>about FreeBSD for our IT support staff. > >>>>> > >>>>>Is fbsd POSIX compliant? Fully? Partially? > >>>>> > >>>>>The info here is a bit out of date: > >>>>> > >>>>>http://www.freebsd.org/projects/c99/index.html > >>>>Looking at the doc its not that out of date. Just check the 9.x > >>>>column. > >>>Oh.. I see. I only looked in the top table. > >>> > >>>Still, I don't get an idea from the table of > >>>how close FreeBSD is to full POSIX compliance. > >>>I guess that's the aim, isn't it? > >>The answer is rather simple. In your presentation you would simple > >>indicate that FreeBSD is not fully compliant. You then have the option > >>of making copies of all the pages referenced in the above URL and > >>including them in the presentation packet you are supplying to the group > >>or simply referring them to the above URL. Figuring out which is more > >>impressive I'll leave up to you. > >sorry to be a pain. > > > >Are we talking 10%, 50%, 90% complete? > > > >Does the above page include all tasks > >that need to be completed? In other words, > >if all tasks on the above page are ticked, > >does this aumtomatically give 100% compliance, > >or is it not that simple? > > > It is not that simple, POSIX is more a set of norms than a norm by > itself. There are Posix aspects that are not in FreeBSD and probably > never will be, other aspects that do exist in FreeBSD but you should > definitly not use them as they are painfull to use or flawed or both > (Posix capabilities for exemple). Also there are systems that do support > a fair part of Posix, but which are just a pain to use in a Posix > compatible environment, basically requiring you to code quite a lot of > tools to have a Posix environment. Basically Windows Server supports > quite a good deal of Posix norms, and it works well for small projects > or simple programs, but if you want to create a Posix compliant > distributed datastore you are in for a hell of a ride. Linux is becoming > basically the same, in that more and more core system tools have > dependencies on Linux specific API. (And I won't talk about MacOS X) > A good way of making a presentation would be to first look at what > aspects of Posix you need and try to find out where these aspect are > best supported. > Now a simple and true enough answer would be to say that FreeBSD has one > of the broader _and most usable_ Posix support, second only to Solaris. > (Way better than AIX and on par with HP-UX in my humble opinion). It is > mostly true in the sense that FreeBSD does support quite a lot of Posix > norms including the latest ones. It is false int the sense that AIX, > HP-UX IRIX and quite alot of others have a 100% certified compliance for > some (quite old now) Posix norms. CF : > http://en.wikipedia.org/wiki/POSIX > http://en.wikipedia.org/wiki/Single_UNIX_Specification#BSD_descendants > > At one point FreeBSD was very close to be fully Posix compliant with > norm 1.e, then norm 1.e was more or less thrown out the windows, and > posix norming system pretty much imploded at this time. > > So basically it is quite hard to answer without first knowing exactly > why you need Posix compliance. It is also worth noting that porting an > application from one fully compliant OS to another is not always easier > than porting from that OS to a non compliant one. Quite a lot of > problems can arise in slightly different interpretations of the norm, > and quite a lot of assumption that are correct under one system will > require carefull tweaking and lib binding in another. > Another thing that is worth noting is that Posix norming system is > dying, I do not know of one system that has compliance above UNIX03, a > norm written in 2001... A very helpful reply, thanks -- Anton Shterenlikht Room 2.6, Queen's Building Mech Eng Dept Bristol University University Walk, Bristol BS8 1TR, UK Tel: +44 (0)117 331 5944 Fax: +44 (0)117 929 4423
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