From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: * X-Spam-Status: No, score=1.3 required=5.0 tests=BAYES_00,INVALID_MSGID, MSGID_RANDY autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,5f8432149982f35e X-Google-Attributes: gid103376,public X-Google-Thread: fca1b,5f8432149982f35e X-Google-Attributes: gidfca1b,public From: Robert Dewar Subject: Re: Ada and QNX Date: 2000/10/16 Message-ID: <8sff6h$q6c$1@nnrp1.deja.com>#1/1 X-Deja-AN: 682139590 References: <8r1i82$ri3$1@kujawiak.man.lodz.pl> <8r5pe5$h70$1@nnrp1.deja.com> <8FCDFD7EEnopenopena@63.209.170.206> <39EA6305.CD5CFE1F@ix.netcom.com> <39EA9161.6469DDE2@home.com> <39EB1BA2.B5F2BFDF@acm.org> <39EB283A.9F7B4F76@motorola.com> X-Http-Proxy: 1.0 x54.deja.com:80 (Squid/1.1.22) for client 205.232.38.14 Organization: Deja.com - Before you buy. X-Article-Creation-Date: Mon Oct 16 17:51:17 2000 GMT X-MyDeja-Info: XMYDJUIDrobert_dewar Newsgroups: comp.lang.ada,comp.os.qnx X-Http-User-Agent: Mozilla/4.61 [en] (OS/2; I) Date: 2000-10-16T00:00:00+00:00 List-Id: In article <39EB283A.9F7B4F76@motorola.com>, Igor Kovalenko wrote: > Summarizing what you and others replied, it looks like everything is > cool with Ada. Just wondering why it is not yet really resurrected and > blooming and shining in all its glory. perhaps because mere technical superiority is not enough. Remember that the really successful programming languages in terms of usage (COBOL, Visual Basic, and I guess even Excel Macro language should count) do not succeed solely because of technical excellence, but because of historical factors. After all Fortran succeeded over Algol-60, and for SURE that was not a matter of superiority of language. I also note that Windows-9X succeeded over OS/2, which is even more surprising. Technical folks always suppose that technical excellence is enough to succeed in the market place. I would have thought that the dominance of Microsoft in the operating system arena (even in the MS DOS days!) would have perhaps reminded people that this is not the case, but .... > Perhaps my personal doubts aren't that personal, huh? and perhaps they most certainly are, a lot of decisions are made on the basis of uninformed personal prejudice of the kind you exhibited. > Nobody appears to write an OS in Ada, being so good for > system level work. Actually Ada would be an excellent technical choice for writing an operating system, the reason that the current operating systems are written in some other language is mostly historical. > And by the way, many people say that GCC does not generate > good code for C Well many people say all sorts of unsupported things (you demonstrate this principle in your post), but that does not mean much. How does gcc compare with other compilers? Well it varies from target to target, it is also pretty hard to judge in some cases, since many proprietary compilers have been specialized carefully to the SPEC suite, and this has not been done for GCC. So you need to be careful what you are comparing. Even if you do use the SPEC suite to compare, gcc often does quite well in the comparison. There are certainly cases where gcc does better than other compilers, and there are cases where it does worse, and of course things are a moving target because gcc is constantly being worked on, and more and more major development depends on gcc (many large scale C users, e.g. AOL, at this stage have standardized on the use of gcc, and large system houses like HP and Sun are definitely paying attention to gcc performance). > So I'm kinda > curious how does GNAT manage to generate good code for such a more > complex language as Ada. It would be easy to satisfy your curiosity, the compiler and sources are out there. > Aside from code generation itself, how do they > manage to implement things like rendesvous in an efficient AND portable > way? Such things normally belong to system-dependent runtime libraries, > but in Ada they are part of language and having no proof I nevertheless > suspect that they are implemented by trading efficiency for portability. You suspect wrong, in fact RV is programmed using standard POSIX primitives that are typically available on all commonly used systems. Now of course RV is a fairly high level abstraction, which you use if you want to abstract at this level. If you want lower level things, then you use them in Ada (indeed there is nothing to stop you using any low level system dependent gizmo that you would use in C if you like). In general you seem a bit too willing to substitute your ill-informed guesses for facts. > It could be that I simply don't know enough and miss something. Yup, it could be :-) > Would be > glad to be enlightened :) > - igor As I say, the sources for GNAT are out there, you are welcome to work on enlightenment! Sent via Deja.com http://www.deja.com/ Before you buy.