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=0.1 required=5.0 tests=BAYES_05,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,4d8577b1627fd192 X-Google-Attributes: gid103376,public From: Robert Love Subject: Re: Ada and ISS Date: 2000/10/18 Message-ID: <60DBAE83940C03E7.BF244DC5EE3E5B00.9935FCDD8D0050E9@lp.airnews.net>#1/1 X-Deja-AN: 683158139 Sender: rlove@smtp.neosoft.com References: <8sb5b0$jo3$1@nnrp1.deja.com> X-Orig-Message-ID: NNTP-Posting-Time: Wed Oct 18 22:19:35 2000 Organization: PDQ.net (using Airnews.net!) NNTP-Proxy-Relay: library1-aux.airnews.net Abuse-Reports-To: abuse at pdq.net to report improper postings Newsgroups: comp.lang.ada Date: 2000-10-18T00:00:00+00:00 List-Id: >>>>> "David" == David Michaels writes: David> Hi Can someone please direct me to a link or a web page David> that might describe Ada's use in the International Space David> Station. I haven't seen much so far so I figure that I'm Web pages on this subject are kind of rare but let me try summarizing. The software that runs on ISS is distributed thru a 3 tiered network of computers called MDM's. They communicate with each other and the devices they control via 1553 protocol. The software that resides in these MDMs is written in Ada, almost exclusively. There is one case, the Guidance and Nav (GNC) MDMs, written in Ada but designed in a tool called MatrixX. Here the designer draws block diagrams of control algorithms and the program writes the Ada that gets compiled. Its not pretty. In the case of the other MDMs, the code is written by people and is "human readable". In all cases I know of, Boeing has written the software for the MDMs in three locations, Houston, Huntsville and Huntington Beach. Now, many of the devices commanded by the MDMs have some type of firmware controller residing in them. The ones I'm familiar with were written in C. Also used on the Space Station are a series of laptop computers called PCS that the crew use to interact with the MDMs. These run Solaris operating system, run X-Windows for displays and are programmed in C or C++. As an aside, I recently heard of a laptop problem where the display for one instrument was not being called up. Seems the programmer had overloaded some C++ function but at runtime it was ambiguous what should really be called and it picked the top entry off of the table which was not the correct function. Mission Control (MCC) can also command most of the operations on the station from Houston. I believe most of the MCC stuff is in C. There is a large contingent that wants to go to all C++. Another large segment devoted to Space Station are the simulators. There are both part task trainers(PTT) and the full task trainer (FTT). The latter is a full up simulator with cockpit mockups and is used to train both the flight crew and the mission controllers. The PTT and FTT are written in Ada by Raytheon in Houston. Only a very small portion of the code is in C or assembler. So, while Ada plays the dominant role in software that goes into orbit on Station it is by no means the sole player, or even a popular one. The cry to switch to C++ is heard often. During the assembly ops that happened Saturday I happened to be monitoring an audio loop from Mission Control where a "controller" was conducting part of a formal procedure. The device being commanded had a minor glitch and I heard one controller ask another what language the device had been programmed in. The answer was C and when the controller who asked the question got the answer he started off about how C++ was a way to "organize the code". These are not programmers but people who work in space operations. But they have acquired the mindset that everything should be in C++. That attitude seems prevalent in all aerospace arenas today. How did we get there? -- ============================================================= | Support Signature Minimalism | =============================================================