From: arne@vajhoej.dk   
      
   On 12/4/2024 10:01 AM, Arne Vajhøj wrote:   
   > On 12/4/2024 8:37 AM, Simon Clubley wrote:   
   >> What is the actual resolution of timer events queued using the   
   >> sys$setimr() system service ?   
   >>   
   >> NOTE: this is about when the timer becomes eligible to fire, not when   
   >> it actually does, given that VMS is not a hard RTOS.   
   >>   
   >> The base VMS time format is in 100ns units, but I couldn't see anything   
   >> about the units actually used when firing timer events. Is it the same   
   >> as the hopeless terminal driver timeouts, or is it 100ns, or is it   
   >> something in between ?   
   >   
   > IDS VMS Alpha 1.5 (30 years old!) says:   
   >   
   >    
   ...   
   >    
   >   
   > which I read as if that on Alpha then VMS checks for SYS$SETIMR   
   > AST's to queue every 1 millisecond.   
   >   
   > No guarantees when the AST's will actually run.   
   >   
   > And some things may have changed in newer VMS versions and   
   > newer hardware.   
      
   https://hunter.goatley.com/writing-vms-privileged-code/part-v-timer-queues/   
      
   has a lot of details.   
      
   But is about the same age as the old IDS.   
      
   Arne   
      
   --- SoupGate-DOS v1.05   
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