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<== Date ==> <== Thread ==>

Subject: bug in the sequencer
From: Jeff Hill <[email protected]>
To: [email protected]
Date: Fri, 22 Nov 1996 11:34:23 -0700
Hello all,

A bug has been discovered in version 1.9.2 of the sequencer.
This bug is in both 3.13 and 3.12.2 of EPICS.

Symptoms:
If there is a state in one of your sequence programs which
matches all of the following conditions then the sequence
program will immediately begin to use all available CPU
and lock out all lower priority tasks such as the CA server.

Conditions Under Which the Bug Occurs
-------------------------------------
o all delay conditions computed within the state have expired
o remain in the same state for 1.9 days (waiting on a PV state change)

Example:
{
        state low
        {
            when(v>5.0&&delay(.1))
            {
                printf("changing to high\n");
            } state high
        }
/* in the above state if v stays below 5.0 for 1.9 days
** the sequence will experience this problem */
       
Fix:
A patch has been applied to epics_R3_12_2_patches and to 3.13.

Jeff and Rozelle

PS: We would like to thank Ned Arnold for experiencing
this problem (and bringing it to our attention).

-- 
______________________________________________________________________
Jeffrey O. Hill                 Internet        [email protected]
LANL MS H820                    Voice           505 665 1831
Los Alamos, NM 87545 USA        FAX             505 665 5107


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