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???
03/21/05 16:32
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Msg Score: +1
 +1 Informative		 #90145 - Unreal Time Explosions
Responding to: ???'s previous message
Erik Malund said:
I can hardly count the software "explosions" I have seen due to insufficient attention to "atomic".

I am sure this would be one answer on "Family Feud" to "what are the causes of intermittent software failures?.

I am sure you will be pleased to know that all pre-emptive URTOSs only make this situation worse. Any regular task code can be pre-emptively suspended and another task code run. If these two tasks share data, they too can suffer the shared data problem if the operations are not atomic as well as the ones you get sharing data with an ISR. To combat this they had to invent semaphores, signals, mailboxes and the like to manage the problem. Not only that, this type of shared data problem is the direct cause of priority inversion which is what nearly buggered up the Mars Rover.

Ian

P.S. The show is called 'Family Fortunes' in the UK.


List of 38 messages in thread
TopicAuthorDate
DS5250 Lockup in ISR's With Priority            01/01/70 00:00      
   Update:            01/01/70 00:00      
      Software Bug            01/01/70 00:00      
      using what            01/01/70 00:00      
         register banks            01/01/70 00:00      
            Shared Data Problem            01/01/70 00:00      
            What stops?            01/01/70 00:00      
               timer isr stops            01/01/70 00:00      
                  Hunting down the ghost            01/01/70 00:00      
   Using different banks            01/01/70 00:00      
      Can't be            01/01/70 00:00      
         stack            01/01/70 00:00      
            more on ISRs            01/01/70 00:00      
         DS5240 has a 1k stack.            01/01/70 00:00      
            but are you using it            01/01/70 00:00      
               Stack            01/01/70 00:00      
   ISRs with Own Register Banks.            01/01/70 00:00      
      Good Questions on ISR's            01/01/70 00:00      
         Shared Data            01/01/70 00:00      
         Not a given            01/01/70 00:00      
            Variable in isr            01/01/70 00:00      
               Sometimes true            01/01/70 00:00      
                  Atomic Operations            01/01/70 00:00      
                     re explosive bytes            01/01/70 00:00      
                        Common Solutions            01/01/70 00:00      
                           Stop's the timer            01/01/70 00:00      
                              Code            01/01/70 00:00      
                        Explosions everywhere            01/01/70 00:00      
                           atomic explosions            01/01/70 00:00      
                              Unreal Time Explosions            01/01/70 00:00      
               Look at the ASM            01/01/70 00:00      
         I have had a very similar problem            01/01/70 00:00      
      ASM instructions & USING            01/01/70 00:00      
         Please do tell us....            01/01/70 00:00      
            Do I really have to?            01/01/70 00:00      
            Brian, Michael            01/01/70 00:00      
               ASM instructions & USING            01/01/70 00:00      
         probably not the case here            01/01/70 00:00      

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