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=1.0 required=5.0 tests=BAYES_00,DATE_IN_PAST_24_48, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: a07f3367d7,1eef1e815cf70416 X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Received: by 10.68.219.170 with SMTP id pp10mr3345757pbc.1.1339700947408; Thu, 14 Jun 2012 12:09:07 -0700 (PDT) X-FeedAbuse: http://nntpfeed.proxad.net/abuse.pl feeded by 78.192.181.72 Path: l9ni50870pbj.0!nntp.google.com!news1.google.com!news4.google.com!feeder1-2.proxad.net!proxad.net!feeder1-1.proxad.net!nntpfeed.proxad.net!78.192.181.72.MISMATCH!gegeweb.42!gegeweb.eu!gegeweb.org!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: Distributed Systems Annex, data sharing between programs Date: Wed, 13 Jun 2012 15:26:52 +0200 Organization: cbb software GmbH 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> <0d661453-423c-484b-90cd-4e80ffe1db5b@6g2000vbv.googlegroups.com> <1dvxe1yiwtw0q$.6h9nlsnpe5ay$.dlg@40tude.net> <3722dc80-de67-4beb-91c8-e05dda0b8aef@googlegroups.com> Reply-To: mailbox@dmitry-kazakov.de NNTP-Posting-Host: FbOMkhMtVLVmu7IwBnt1tw.user.speranza.aioe.org Mime-Version: 1.0 X-Complaints-To: abuse@aioe.org User-Agent: 40tude_Dialog/2.0.15.1 X-Notice: Filtered by postfilter v. 0.8.2 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Date: 2012-06-13T15:26:52+02:00 List-Id: On Wed, 13 Jun 2012 03:55:47 -0700 (PDT), Marius Amado-Alves wrote: >> Our middleware supports synchronous calls, but they are implemented on top >> of an asynchronous layer as send/request + wait. (Kasakov) > > (Secret technology?) Just proprietary > This thread is fascinating. > > Make RPC based on messages (Kasakov and others) or vice versa (Obry and others)? No, our middleware is not message-oriented and generally not client-server. it uses process variables instead and has the topology of a bus. (Messaging could be a transport) > FWIW, I tend towards the latter. It's clearly the Ada way: > > Ada offers asyncronous control already. (which most likely does not work a naive reader would expect) > Distribution and synchronicity are orthogonal dimensions. Yes. With distribution come issues like quality of data and other attributes of values missing or handled differently in monolithic coherent applications. There you would simply handle poor quality as exceptional (or even a bug), raising Data_Error or Constraint_Error. In a distributed application you usually have competing sources of data and errors related to the availability of these sources. You rather store quality, timestamp etc as additional attributes instead of raising exceptions, which cannot be handled meaningfully right now and here. It is a different mindset. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de