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=0.4 required=5.0 tests=BAYES_00,FORGED_MUA_MOZILLA autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,1eef1e815cf70416 X-Google-NewGroupId: yes X-Google-Attributes: gida07f3367d7,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Received: by 10.204.157.134 with SMTP id b6mr4284633bkx.5.1339012965157; Wed, 06 Jun 2012 13:02:45 -0700 (PDT) Path: e27ni21119bkw.0!nntp.google.com!news2.google.com!news3.google.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: Niklas Holsti Newsgroups: comp.lang.ada Subject: Re: Distributed Systems Annex, data sharing between programs Date: Wed, 06 Jun 2012 22:02:42 +0200 Organization: Tidorum Ltd Message-ID: References: <8055acf5-188f-4b34-b4f0-83d70fee54f8@googlegroups.com> <96feb838-e0d3-4d06-abf0-79a8e74b5746@e20g2000vbm.googlegroups.com> <54af7ad7-7268-4d84-bafa-542e380a58f6@n16g2000vbn.googlegroups.com> Mime-Version: 1.0 X-Trace: individual.net r2FhAMHtcCmKAuv3dMYtowVW0m6KbCZXNGOvI9XmAf4GkQpVfwYH/Jct8h/hcPb+J5 Cancel-Lock: sha1:ochme9ZFEpZuI07Zi/BgSLtWwxY= User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 In-Reply-To: <54af7ad7-7268-4d84-bafa-542e380a58f6@n16g2000vbn.googlegroups.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Date: 2012-06-06T22:02:42+02:00 List-Id: On 12-06-06 13:40 , Maciej Sobczak wrote: > On 6 Cze, 12:09, Niklas Holsti wrote: > >>> This is what makes single-language-distributed-systems solutions kind >>> of pointless. >> >> The fact that *some* distributed systems are multi-language does not >> mean that a single-language solution is pointless. Insufficient, perhaps. > > Single-language systems (A) are a subset of multi-language systems > (B). This means that if you need the B solution anyway (and you really > need it) and it solve problem A as well, then having a separate A > solution is pointless. They don't solve the "same" problem, or not equally well. A single-language solution can offer better integration, more compile-time checks, and less effort on middleware tools (less effort by the application developer, at least). I don't agree that the Ada DSA is "pointless", although it is not used in as many applications as the multi-language interfaces. > You might still ask for it for performance reasons (it is easier to > achieve good performance if you are not constrained by artificial > common denominators), It can also offer better degree of integration, safety, logical consistency. > but this is a luxury that can be afforded only > when you have other burning problems sorted out already. > Unfortunately, this is not the case for Ada and that is why I argue > that this is an effort that is better spent elsewhere. Is a lot of effort (still) needed for the DSA? Perhaps it is, since only AdaCore support it -- or are there others? >> In your experience, are >> IDLs like CORBA used today? Or just sockets with ad-hoc protocols? > > I think that plain sockets are not very widely used by mature > development teams and instead some ready protocols are adopted with > varying degrees of completeness. CORBA is complete but huge and it > seems to be less and less popular, but there are plenty of other > solutions somewhere in this spectrum. > One of the small, but potentially useful things I have found recently > is this: > > http://msgpack.org/ > > It is not complete in the sense that it covers only the serialization > part (and even there has many limitations), but for a number of > problems seems like a nice and easy, off-hand solution. Yes, the Ada > binding is missing there. MessagePack looks potentially useful, but I also think it illustrates the drawbacks of a multi-language middleware compared to the Ada DSA, such as a limitation to low-level "physical" types. > And of course, I will benefit from the opportunity to shamelessly > mention this: > > http://inspirel.com/yami4/ Nice tutorial video. But here, too, I get the impression of working one layer below the DSA level, mostly. Usable, and good for cross-language work, but still missing some of the high-level integrity of the DSA level. -- Niklas Holsti Tidorum Ltd niklas holsti tidorum fi . @ .