07-25-2005, 06:11 AM | #1 |
Carmudgeon
Join Date: Jul 2004
Carmudgeonly Ride: Invalid Carriage
Location: Bay Area, CA
Posts: 1,932
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Scary :speechless:
So as I creep ever-closer to the first of the BMW classes, I've started to look more *in-depth* into the operations of your average "modern" BMW. How these things manage to go down the road without grinding to an irreparable halt, I don't know. And that's the amazing thing, really - when learning more about cars, the oft-heard observation is not "Wow, it's so cool that it works that way!" but more "Damn, I can't believe they actually make all this shit work, and that it don't uselessly leave their owners on the side of the road all the time."
So what kind of madness am I talking about? Here's the BUS SYSTEM structure of our favorite bangle-fied 7-series. It has been posted before: And here it is, the legible edition: Let's zoom in on the K-CAN S and K-CAN P area (K-CAN stands for Body-Controller Area Network): Inside it , we find the following computer modules: K-CAN S - Body-CAN System Automobile body main line system AHM----TRAILER module BZM----CENTER console operating center BZMF----CENTER console operating center rear CIM----CHASSIS integration module CON----CONTROLLER DWA----ANTI-Theft alarm system IHKA----INTEGRATED heating and air conditioning LM----LIGHT module PDC----PARK distance control RDC----TYRE pressure warning system RLS----RAIN/LIGHT sensor SH----PARK heating SHD----SLIDE/TILT sunroof WIM----WIPER module K-CAN P - Body-CAN Periphery Automobile body periphery main line CAS----CAR access system HKL----TAILGATE lift PM----POWER module SMBF----PASSENGER seat module SMBFH----PASSENGER seat module rear SMFA----DRIVER seat module SMFAH----DRIVER seat module rear TMBFT----DOOR module passenger door TMBFTH----DOOR module passenger door rear TMFAT----DOOR module driver door TMFATH----DOOR module driver door rear Those aren't even the fiber-optic networks (that would be MOST and byteflight). More in the next few months. "You just ask some of the students here and they'll tell ya - how hard can it be, power window controls? You think, it's a power window - I press the button, it goes up, it goes down. There! That's it. Simple as that. Oh no, it isn't! You got regular up, down, soft up and down, one-touch up and down, you can do it with the turn of the key, the keyfob, anti-trap, disabling anti-trap for the windows AND the moonroof, two different modes when disabling it..." -BMW Instructor |
07-25-2005, 08:50 AM | #2 |
lawn boy
Join Date: Oct 2003
Carmudgeonly Ride: e46m3, f25x3,C5 Z06, C4 Vette, 06 CTD Ram, and a trailer
Location: Maryland
Posts: 14,029
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Let me know when they start hiring network admins to work on these things.
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07-25-2005, 09:18 AM | #3 | |
Mugwump
Join Date: Oct 2003
Carmudgeonly Ride: E46 330i, Chevy Colorado, Tesla Model 3
Location: NY
Posts: 17,475
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I've wondered for a long time how cars, as well as other things like planes, etc, don't fail more often as their complexity increases. In the software industry, the complexity of the software produced is well beyond the developers and testers ability to understand it completely and test it fully. Hence, software sucks ass, and crashes all the time. Why it's not the same for cars, planes, bridges, etc.. I don't know. Maybe just just spend more on testing because problems are more costly to fix than they are in software? |
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07-25-2005, 09:34 AM | #4 | ||
No more BMWs
Join Date: Apr 2005
Carmudgeonly Ride: Ram, MS3, CX-5, RX-8
Location: Glenwood, MD
Posts: 14,753
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07-25-2005, 09:47 AM | #5 | |||
Chillaxin'
Join Date: Oct 2003
Carmudgeonly Ride: '05 C50, '04 F-150
Location: CA
Posts: 6,302
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The only other thing I would add is that buses, on paper, look deceiving. There is a complex modulation/demodulation scheme involved. It is like a signal heirarchy or route, to put it simply,messages rarely get crossed or interfered with as long as mod/demod and terminations are used correctly. |
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07-25-2005, 09:54 AM | #6 |
Doctor Mudgeon
Join Date: Oct 2003
Posts: 6,433
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Don't forget that a software crash in a moving vehicle can be deadly. A software crash in most office environments is just really annoying. My guess is that vehicle systems are actually less complicated than most software packages, that they have some level of redundancy built in, and that they're tested as rigorously as possible during development. After all, it still takes manufacturers over a year to develop a new model; that's enough time to work out the kinks if everyone works hard.
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07-25-2005, 10:19 AM | #7 | |
Chillaxin'
Join Date: Oct 2003
Carmudgeonly Ride: '05 C50, '04 F-150
Location: CA
Posts: 6,302
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07-25-2005, 10:53 AM | #8 |
Chief title editor
Join Date: Oct 2003
Posts: 26,599
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Don't forget that the software running in cars is generally running on a known specific set of hardware without competition from other unknown application that may or may not be running (and specifically, running properly) all on top of a bug filled OS (for these purposes, I'm referring to ALL desktop OSs).
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OH NOES!!!!!1 MY CAR HAS T3H UND3R5T33R5555!!!!!!1oneone!!!!11 Team WTF?! What are you gonna do? |
07-25-2005, 12:53 PM | #9 | |
Solving problems
Join Date: Oct 2003
Carmudgeonly Ride: M5 / 718 GTS / Cooper S / GTI / LR4
Location: Metro Boston
Posts: 25,248
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07-25-2005, 01:12 PM | #10 | |
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Join Date: Mar 2004
Posts: 13,514
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