diff --git a/src/libCom/test/epicsTimerTest.cpp b/src/libCom/test/epicsTimerTest.cpp
index bcac7e38f..ae790946e 100644
--- a/src/libCom/test/epicsTimerTest.cpp
+++ b/src/libCom/test/epicsTimerTest.cpp
@@ -40,7 +40,6 @@ static const double delayVerifyOffset = 1.0; // sec
 class delayVerify : public epicsTimerNotify {
 public:
     delayVerify ( double expectedDelay, epicsTimerQueue & );
-    expireStatus expire ();
     void * operator new ( size_t size );
     void operator delete ( void *pCadaver, size_t size );
     void start ( const epicsTime &expireTime );
@@ -54,6 +53,7 @@ private:
     epicsTime beginStamp;
     epicsTime expireStamp;
     double expectedDelay;
+    expireStatus expire ( const epicsTime & );
     static tsFreeList < class delayVerify, 0x20 > freeList;
     static epicsMutex freeListMutex;
 };
@@ -62,7 +62,7 @@ static unsigned expireCount;
 static epicsEvent expireEvent;
 
 delayVerify::delayVerify ( double expectedDelayIn, epicsTimerQueue &queue ) :
-    timer ( queue.createTimer ( *this ) ), expectedDelay ( expectedDelayIn )
+    timer ( queue.createTimer() ), expectedDelay ( expectedDelayIn )
 {
 }
 
@@ -95,7 +95,7 @@ void delayVerify::checkError () const
 
 inline void delayVerify::start ( const epicsTime &expireTime )
 {
-    this->timer.start ( expireTime );
+    this->timer.start ( *this, expireTime );
 }
 
 tsFreeList < class delayVerify, 0x20 > delayVerify::freeList;
@@ -113,9 +113,9 @@ inline void delayVerify::operator delete ( void *pCadaver, size_t size )
     delayVerify::freeList.release ( pCadaver, size );
 }
 
-epicsTimerNotify::expireStatus delayVerify::expire ()
+epicsTimerNotify::expireStatus delayVerify::expire ( const epicsTime &currentTime )
 {
-    this->expireStamp = epicsTime::getCurrent ();
+    this->expireStamp = currentTime;
     if ( --expireCount == 0u ) {
         expireEvent.signal ();
     }
@@ -156,7 +156,6 @@ void testAccuracy ()
 class cancelVerify : public epicsTimerNotify {
 public:
     cancelVerify ( epicsTimerQueue & );
-    expireStatus expire ();
     void * operator new ( size_t size );
     void operator delete ( void *pCadaver, size_t size );
     void start ( const epicsTime &expireTime );
@@ -166,12 +165,13 @@ protected:
 private:
     epicsTimer &timer;
     bool failOutIfExpireIsCalled;
+    expireStatus expire ( const epicsTime & );
     static tsFreeList < class cancelVerify, 0x20 > freeList;
     static epicsMutex freeListMutex;
 };
 
 cancelVerify::cancelVerify ( epicsTimerQueue &queue ) :
-    timer ( queue.createTimer ( *this ) ), failOutIfExpireIsCalled ( false )
+    timer ( queue.createTimer () ), failOutIfExpireIsCalled ( false )
 {
 }
 
@@ -182,7 +182,7 @@ cancelVerify::~cancelVerify ()
 
 inline void cancelVerify::start ( const epicsTime &expireTime )
 {
-    this->timer.start ( expireTime );
+    this->timer.start ( *this, expireTime );
 }
 
 tsFreeList < class cancelVerify, 0x20 > cancelVerify::freeList;
@@ -206,7 +206,7 @@ inline void cancelVerify::cancel ()
     this->failOutIfExpireIsCalled = true;
 }
 
-epicsTimerNotify::expireStatus cancelVerify::expire ()
+epicsTimerNotify::expireStatus cancelVerify::expire ( const epicsTime & )
 {
     double root = 3.14159;
     for ( unsigned i = 0u; i < 10000; i++ ) {
@@ -247,7 +247,6 @@ void testCancel ()
 class periodicVerify : public epicsTimerNotify {
 public:
     periodicVerify ( epicsTimerQueue & );
-    expireStatus expire ();
     void * operator new ( size_t size );
     void operator delete ( void *pCadaver, size_t size );
     void start ( const epicsTime &expireTime );
@@ -259,12 +258,13 @@ private:
     unsigned nExpire;
     epicsTimer &timer;
     bool failOutIfExpireIsCalled;
+    expireStatus expire ( const epicsTime & );
     static tsFreeList < class periodicVerify, 0x20 > freeList;
     static epicsMutex freeListMutex;
 };
 
 periodicVerify::periodicVerify ( epicsTimerQueue &queue ) :
-    nExpire ( 0u ), timer ( queue.createTimer ( *this ) ), failOutIfExpireIsCalled ( false )
+    nExpire ( 0u ), timer ( queue.createTimer () ), failOutIfExpireIsCalled ( false )
 {
 }
 
@@ -275,7 +275,7 @@ periodicVerify::~periodicVerify ()
 
 inline void periodicVerify::start ( const epicsTime &expireTime )
 {
-    this->timer.start ( expireTime );
+    this->timer.start ( *this, expireTime );
 }
 
 tsFreeList < class periodicVerify, 0x20 > periodicVerify::freeList;
@@ -304,7 +304,7 @@ inline void periodicVerify::verifyCount ()
     assert ( this->nExpire > 1u );
 }
 
-epicsTimerNotify::expireStatus periodicVerify::expire ()
+epicsTimerNotify::expireStatus periodicVerify::expire ( const epicsTime & )
 {
     this->nExpire++;
     double root = 3.14159;
diff --git a/src/libCom/timer/epicsTimer.cpp b/src/libCom/timer/epicsTimer.cpp
index 0a20882b0..ea00674c2 100644
--- a/src/libCom/timer/epicsTimer.cpp
+++ b/src/libCom/timer/epicsTimer.cpp
@@ -43,7 +43,7 @@ protected:
 private:
     epicsTimerCallback pCallBack;
     void * pPrivate;
-    expireStatus expire ();
+    expireStatus expire ( const epicsTime & currentTime );
     static tsFreeList < epicsTimerForC > freeList;
     static epicsMutex freeListMutex;
 };
@@ -70,7 +70,7 @@ tsFreeList < epicsTimerForC > epicsTimerForC::freeList;
 epicsMutex epicsTimerForC::freeListMutex;
 
 epicsTimerForC::epicsTimerForC ( timerQueue &queue, epicsTimerCallback pCBIn, void *pPrivateIn ) :
-    timer ( *this, queue ), pCallBack ( pCBIn ), pPrivate ( pPrivateIn )
+    timer ( queue ), pCallBack ( pCBIn ), pPrivate ( pPrivateIn )
 {
 }
 
@@ -95,7 +95,7 @@ inline void epicsTimerForC::operator delete ( void *pCadaver, size_t size )
     epicsTimerForC::freeList.release ( pCadaver, size );
 }
 
-epicsTimerNotify::expireStatus epicsTimerForC::expire ()
+epicsTimerNotify::expireStatus epicsTimerForC::expire ( const epicsTime & )
 {
     ( *this->pCallBack ) ( this->pPrivate );
     return noRestart;
@@ -171,17 +171,10 @@ extern "C" void epicsShareAPI
     pQueue->destroy ();
 }
 
-extern "C" void epicsShareAPI 
+extern "C" double epicsShareAPI 
     epicsTimerQueuePassiveProcess ( epicsTimerQueuePassiveId pQueue )
 {
-    pQueue->process ();
-}
-
-extern "C" double epicsShareAPI 
-    epicsTimerQueuePassiveGetDelayToNextExpire (
-        epicsTimerQueuePassiveId pQueue )
-{
-    return pQueue->getNextExpireDelay ();
+    return pQueue->process ( epicsTime::getCurrent() );
 }
 
 extern "C" epicsTimerId epicsShareAPI epicsTimerQueuePassiveCreateTimer (
@@ -243,13 +236,13 @@ extern "C" void  epicsShareAPI epicsTimerDestroy ( epicsTimerId pTmr )
 extern "C" void  epicsShareAPI epicsTimerStartTime (
     epicsTimerId pTmr, const epicsTimeStamp *pTime )
 {
-    pTmr->start ( *pTime );
+    pTmr->start ( *pTmr, *pTime );
 }
 
 extern "C" void  epicsShareAPI epicsTimerStartDelay (
     epicsTimerId pTmr, double delaySeconds )
 {
-    pTmr->start ( delaySeconds );
+    pTmr->start ( *pTmr, delaySeconds );
 }
 
 extern "C" void  epicsShareAPI epicsTimerCancel ( epicsTimerId pTmr )
diff --git a/src/libCom/timer/epicsTimer.h b/src/libCom/timer/epicsTimer.h
index 573ec1024..109fa5c2e 100644
--- a/src/libCom/timer/epicsTimer.h
+++ b/src/libCom/timer/epicsTimer.h
@@ -20,6 +20,11 @@ of this distribution.
 
 #ifdef __cplusplus
 
+//
+// Notes:
+// 1) epicsTimer does not hold its lock when calling callbacks.
+//
+
 // code using a timer must implement epicsTimerNotify
 class epicsTimerNotify {
 public:
@@ -35,23 +40,29 @@ public:
         double delay;
     };
     // return noRestart OR return expireStatus ( restart, 30.0 /* sec */ );
-    virtual expireStatus expire () = 0;
+    virtual expireStatus expire ( const epicsTime & currentTime ) = 0;
     virtual epicsShareFunc void show ( unsigned int level ) const;
 };
 
 class epicsTimer {
 public:
     virtual ~epicsTimer () = 0;
-    virtual void start ( const epicsTime & ) = 0;
-    virtual void start ( double delaySeconds ) = 0;
+    virtual void start ( epicsTimerNotify &, const epicsTime & ) = 0;
+    virtual void start ( epicsTimerNotify &, double delaySeconds ) = 0;
     virtual void cancel () = 0;
-    virtual double getExpireDelay () const = 0;
+    struct expireInfo {
+        expireInfo ( bool active, const epicsTime &expireTime );
+        bool active;
+        epicsTime expireTime;
+    };
+    virtual expireInfo getExpireInfo () const = 0;
+    double getExpireDelay ();
     virtual void show ( unsigned int level ) const = 0;
 };
 
 class epicsTimerQueue {
 public:
-    virtual epicsTimer & createTimer ( epicsTimerNotify & ) = 0;
+    virtual epicsTimer & createTimer () = 0;
     virtual void show ( unsigned int level ) const = 0;
 protected:
     virtual ~epicsTimerQueue () = 0;
@@ -77,8 +88,7 @@ class epicsTimerQueuePassive : public epicsTimerQueue {
 public:
     static epicsShareFunc epicsTimerQueuePassive & create ( epicsTimerQueueNotify & );
     virtual ~epicsTimerQueuePassive () = 0;
-    virtual void process () = 0;
-    virtual double getNextExpireDelay () const = 0;
+    virtual double process ( const epicsTime & currentTime ) = 0; // returns delay to next expire
 };
 
 inline epicsTimerNotify::expireStatus::expireStatus ( restart_t restart ) : 
@@ -105,6 +115,27 @@ inline double epicsTimerNotify::expireStatus::expirationDelay () const
     return this->delay;
 }
 
+inline epicsTimer::expireInfo::expireInfo ( bool activeIn, 
+    const epicsTime & expireTimeIn ) :
+        active ( activeIn ), expireTime ( expireTimeIn ) 
+{
+}
+
+inline double epicsTimer::getExpireDelay ()
+{
+    epicsTimer::expireInfo info = this->getExpireInfo ();
+    if ( info.active ) {
+        double delay = info.expireTime - epicsTime::getCurrent ();
+        if ( delay < 0.0 ) {
+            delay = 0.0;
+        }
+        return delay;
+    }
+    else {
+        return - DBL_MAX;
+    }
+}
+
 extern "C" {
 #endif /* __cplusplus */
 
@@ -133,11 +164,8 @@ epicsShareFunc void epicsShareAPI
 epicsShareFunc epicsTimerId epicsShareAPI 
     epicsTimerQueuePassiveCreateTimer (
         epicsTimerQueuePassiveId queueid, epicsTimerCallback pCallback, void *pArg );
-epicsShareFunc void epicsShareAPI 
-    epicsTimerQueuePassiveProcess ( epicsTimerQueuePassiveId );
 epicsShareFunc double epicsShareAPI 
-    epicsTimerQueuePassiveGetDelayToNextExpire (
-        epicsTimerQueuePassiveId );
+    epicsTimerQueuePassiveProcess ( epicsTimerQueuePassiveId );
 epicsShareFunc void  epicsShareAPI epicsTimerQueuePassiveShow (
     epicsTimerQueuePassiveId id, unsigned int level );
 
diff --git a/src/libCom/timer/osiTimer.cpp b/src/libCom/timer/osiTimer.cpp
deleted file mode 100644
index b29e3e1d6..000000000
--- a/src/libCom/timer/osiTimer.cpp
+++ /dev/null
@@ -1,714 +0,0 @@
-/*
- *      $Id$
- *
- *      Author  Jeffrey O. Hill
- *              johill@lanl.gov
- *              505 665 1831
- *
- *      Experimental Physics and Industrial Control System (EPICS)
- *
- *      Copyright 1991, the Regents of the University of California,
- *      and the University of Chicago Board of Governors.
- *
- *      This software was produced under  U.S. Government contracts:
- *      (W-7405-ENG-36) at the Los Alamos National Laboratory,
- *      and (W-31-109-ENG-38) at Argonne National Laboratory.
- *
- *      Initial development by:
- *              The Controls and Automation Group (AT-8)
- *              Ground Test Accelerator
- *              Accelerator Technology Division
- *              Los Alamos National Laboratory
- *
- *      Co-developed with
- *              The Controls and Computing Group
- *              Accelerator Systems Division
- *              Advanced Photon Source
- *              Argonne National Laboratory
- *
- */
-
-#ifndef assert // allow use of epicsAssert.h
-#include <assert.h>
-#endif
-#include <stdio.h>
-#include <float.h>
-
-#define epicsExportSharedSymbols
-#include "osiTimer.h"
-#include "locationException.h"
-#include "errlog.h"
-
-class osiTimerThread : public epicsThreadRunable {
-public:
-    osiTimerThread (osiTimerQueue &, unsigned priority);
-    virtual ~osiTimerThread();
-private:
-    friend class osiTimer;
-    friend class osiTimerQueue;
-    epicsThread thread;
-    osiTimerQueue &queue;
-
-    virtual void run();
-};
-
-//
-// default global timer queue
-//
-osiTimerQueue osiDefaultTimerQueue ( osiTimerQueue::mtsNoManagerThread );
-
-//
-// osiTimer::osiTimer ()
-//
-// create an active timer that will expire in delay seconds
-//
-osiTimer::osiTimer (double delay, osiTimerQueue & queueIn) :
-    queue (queueIn)
-{
-	this->arm (delay);
-}
-
-//
-// osiTimer::osiTimer ()
-//
-// create an active timer that will expire in delay seconds
-//
-osiTimer::osiTimer (double delay) :
-    queue (osiDefaultTimerQueue)
-{
-	this->arm (delay);
-}
-
-//
-// osiTimer::osiTimer ()
-//
-// create an inactive timer
-//
-osiTimer::osiTimer (osiTimerQueue & queueIn) :
-curState (osiTimer::stateIdle), queue (queueIn) 
-{
-    epicsAutoMutex ( this->queue.mutex );
-	this->queue.timerLists[stateIdle].add (*this);
-}
-
-//
-// osiTimer::osiTimer ()
-//
-// create an inactive timer
-//
-osiTimer::osiTimer () :
-curState (osiTimer::stateIdle), queue (osiDefaultTimerQueue) 
-{
-    epicsAutoMutex ( this->queue.mutex );
-	this->queue.timerLists[stateIdle].add (*this);
-}
-
-//
-// osiTimer::~osiTimer()
-//
-osiTimer::~osiTimer()
-{
-    if ( this->curState == stateLimbo ) {
-        return; // queue was destroyed
-    }
-
-    epicsAutoMutex ( this->queue.mutex );
-	//
-	// signal the timer queue if this
-	// occurring during the expire call
-	// back
-	//	    
-    if (this == this->queue.pExpireTmr) {
-		this->queue.pExpireTmr = 0;
-	}
-    this->queue.timerLists[this->curState].remove(*this);
-    this->curState = stateLimbo;
-}
-
-//
-// osiTimer::cancel ()
-//
-void osiTimer::cancel ()
-{
-    if ( this->curState == stateLimbo ) {
-        return; // queue was destroyed
-    }
-
-    {
-        epicsAutoMutex ( this->queue.mutex );
-
-	    //
-	    // signal the timer queue if this
-	    // occurring during the expire call
-	    // back
-	    //	    
-        if (this == this->queue.pExpireTmr) {
-		    this->queue.pExpireTmr = 0;
-	    }
-
-        this->queue.timerLists[this->curState].remove (*this);
-        this->curState = stateIdle;
-        this->queue.timerLists[stateIdle].add (*this);
-    }
-
-    this->destroy ();
-}
-
-//
-// osiTimer::reschedule()
-// 
-// pull this timer out of the queue and reinstall
-// it with a new experation time
-//
-void osiTimer::reschedule ()
-{
-    this->reschedule ( this->delay () );
-}
-
-//
-// osiTimer::reschedule()
-// 
-// pull this timer out of the queue ans reinstall
-// it with a new experation time
-//
-void osiTimer::reschedule (double newDelay)
-{
-    if ( this->curState == stateLimbo ) {
-        return; // queue was destroyed
-    }
-
-    epicsAutoMutex ( this->queue.mutex );
-
-	//
-	// signal the timer queue if this
-	// occurring during the expire call
-	// back
-	//	    
-    if ( this == this->queue.pExpireTmr ) {
-		this->queue.pExpireTmr = 0;
-	}
-    this->queue.timerLists[this->curState].remove (*this);
-    this->curState = stateLimbo;
-    this->arm (newDelay);
-}
-
-//
-// Start the timer with delay this->delay() if inactive
-// 
-epicsShareFunc void osiTimer::activate ()
-{
-    this->activate ( this->delay () );
-}
-
-//
-// Start the timer with delay newDelay if inactive
-// 
-epicsShareFunc void osiTimer::activate ( double newDelay )
-{
-    if ( this->curState == stateLimbo ) {
-        return; // queue was destroyed
-    }
-
-    epicsAutoMutex ( this->queue.mutex );
-
-    if ( this->curState == stateIdle ) {
-	    //
-	    // signal the timer queue if this
-	    // occurring during the expire call
-	    // back
-	    //	    
-        if ( this == this->queue.pExpireTmr ) {
-		    this->queue.pExpireTmr = 0;
-	    }
-        this->queue.timerLists[this->curState].remove (*this);
-        this->curState = stateLimbo;
-        this->arm (newDelay);
-    }
-}
-
-//
-// osiTimer::arm ()
-//
-void osiTimer::arm (double initialDelay)
-{
-    bool first;
-
-#	ifdef DEBUG
-	    unsigned preemptCount = 0u;
-#	endif
-
-    {
-        epicsAutoMutex ( this->queue.mutex );
-
-        //
-        // create manager thread on demand so we dont have threads hanging
-        // around that are not used
-        //
-        if ( ! this->queue.terminateFlag && this->queue.pMgrThread == NULL ) {
-            this->queue.pMgrThread = new osiTimerThread (this->queue, this->queue.mgrThreadPriority);
-            if ( this->queue.pMgrThread == NULL ) {
-                throwWithLocation ( noMemory () );
-            }
-        }
-
-	    //
-	    // calculate absolute expiration time
-	    //
-	    this->exp = epicsTime::getCurrent () + initialDelay;
-
-	    //
-	    // insert into the pending queue
-	    //
-	    // Finds proper time sorted location using
-	    // a linear search.
-	    //
-	    // **** this should use a binary tree ????
-	    //
-	    tsDLIterBD<osiTimer> iter = this->queue.timerLists[statePending].lastIter ();
-	    while (1) {
-		    if ( ! iter.valid () ) {
-			    //
-			    // add to the beginning of the list
-			    //
-			    this->queue.timerLists[statePending].push (*this);
-                first = true;
-			    break;
-		    }
-		    if ( iter->exp <= this->exp ) {
-			    //
-			    // add after the item found that expires earlier
-			    //
-			    this->queue.timerLists[statePending].insertAfter (*this, *iter);
-                first = false;
-			    break;
-		    }
-#		    ifdef DEBUG
-		        preemptCount++;
-#		    endif
-		    --iter;
-	    }
-
-	    this->curState = osiTimer::statePending;
-
-#	    ifdef DEBUG
-	        this->show (10u);
-#	    endif
-	    
-#	    ifdef DEBUG 
-	        //
-	        // name virtual function isnt always useful here because this is
-	        // often called inside the constructor (unless we are
-	        // rearming the same timer)
-	        //
-	        printf ("Arm of \"%s\" with delay %f at %lx preempting %u\n", 
-		        this->name(), initialDelay, (unsigned long)this, preemptCount);
-    #	endif
-    }
-
-    if (first) {
-        this->queue.rescheduleEvent.signal ();
-    }
-}
-
-//
-// osiTimer::again()
-//
-bool osiTimer::again () const
-{
-	//
-	// default is to run the timer only once 
-	//
-	return false;
-}
-
-//
-// osiTimer::destroy()
-//
-void osiTimer::destroy ()
-{
-	delete this;
-}
-
-//
-// osiTimer::delay()
-//
-double osiTimer::delay () const
-{
-    throwWithLocation ( noDelaySpecified () );
-    return DBL_MAX; // never here
-}
-
-//
-// osiTimer::show()
-//
-void osiTimer::show (unsigned level) const
-{
-	epicsTime	cur = epicsTime::getCurrent ();
-	printf ("osiTimer at %p for \"%s\" with again = %d\n", 
-		static_cast <const void *> (this), this->name(), this->again());
-	if (level>=1u) {
-	    double delay = this->exp - cur;
-		printf ("\tdelay to expire = %f, state = %d\n", 
-			delay, this->curState);
-	}
-}
-
-//
-// osiTimer::name()
-// virtual base default 
-//
-const char *osiTimer::name() const
-{
-	return "osiTimer";
-}
-
-//
-// osiTimer::timeRemaining()
-//
-// return the number of seconds remaining before
-// this timer will expire
-//
-double osiTimer::timeRemaining () const
-{
-    double delay;
-
-    epicsAutoMutex ( this->queue.mutex );
-
-    switch (this->curState) {
-    case statePending:
-	    delay = this->exp - epicsTime::getCurrent();
-	    if ( delay < 0.0 ) {
-		    delay = 0.0;
-	    }
-        break;
-
-    case stateIdle:
-        delay = DBL_MAX;
-        break;
-
-    case stateExpired:
-        delay = 0.0;
-        break;
-
-    case stateLimbo:
-        errlogPrintf ("time remaning fetched on a osiTimer with no queue?\n");
-        delay = DBL_MAX; // queue was destroyed
-        break;
-
-    default:
-        errlogPrintf ("saw osiTimer in undefined state\n");
-        delay = DBL_MAX;
-        break;
-    }
-
-    return delay;
-}
-
-//
-// osiTimerQueue::osiTimerQueue ()
-//
-epicsShareFunc osiTimerQueue::osiTimerQueue ( managerThreadSelect mts, 
-                              unsigned managerThreadPriority ) :
-    pExpireTmr (0), pMgrThread (0), mgrThreadPriority (managerThreadPriority), 
-    inProcess (false), exitFlag (false)
-{
-    this->terminateFlag = ( mts != mtsCreateManagerThread );
-}
-
-//
-// osiTimerQueue::~osiTimerQueue()
-//
-osiTimerQueue::~osiTimerQueue()
-{
-	osiTimer *pTmr;
-
-    this->terminateManagerThread ();
-
-    this->mutex.lock ();
-
-	//
-	// destroy any unexpired timers
-	//
-    while ( ( pTmr = this->timerLists[osiTimer::statePending].get () ) ) {	
-		pTmr->curState = osiTimer::stateLimbo;
-		pTmr->destroy ();
-	}
-
-	//
-	// destroy any expired timers
-	//
-	while ( (pTmr = this->timerLists[osiTimer::stateExpired].get()) ) {	
-		pTmr->curState = osiTimer::stateLimbo;
-		pTmr->destroy ();
-	}
-}
-
-//
-// osiTimerQueue::terminateManagerThread ()
-//
-void osiTimerQueue::terminateManagerThread ()
-{
-    // stop current thread if started and
-    // prevent launching of thread in the future
-    this->terminateFlag = true;
-    if ( this->pMgrThread ) {
-        
-        this->rescheduleEvent.signal ();
-
-        while ( ! this->exitFlag && ! this->pMgrThread->thread.isSuspended () ) {
-            this->exitEvent.wait ( 1.0 );
-        }
-
-        {
-            epicsAutoMutex ( this->mutex );
-            if ( this->pMgrThread ) {
-                delete this->pMgrThread;
-                this->pMgrThread = 0;
-            }
-        }
-
-        // in case other threads are waiting here also
-        this->exitEvent.signal ();
-    }
-}
-
-//
-// osiTimerThread::osiTimerThread ()
-//
-osiTimerThread::osiTimerThread (osiTimerQueue &queueIn, unsigned priority) :
-    thread( *this, "osiTimerQueue",
-        epicsThreadGetStackSize (epicsThreadStackMedium), priority) , 
-    queue (queueIn)
-{
-    this->thread.start ();
-}
-
-osiTimerThread::~osiTimerThread() {};
-
-//
-// osiTimerThread::run ()
-//
-void osiTimerThread::run ()
-{
-    queue.exitFlag = false;
-    while ( ! queue.terminateFlag ) {
-        queue.privateProcess ();
-        double delay = queue.delayToFirstExpire ();
-        queue.rescheduleEvent.wait ( delay );
-    }
-    queue.exitFlag = true; 
-    queue.exitEvent.signal (); // no access to queue after exitEvent signal
-}
-
-//
-// osiTimerQueue::delayToFirstExpire ()
-//
-double osiTimerQueue::delayToFirstExpire () const
-{
-	osiTimer *pTmr;
-	double delay;
-
-    epicsAutoMutex locker ( this->mutex );
-
-    pTmr = this->timerLists[osiTimer::statePending].first ();
-	if (pTmr) {
-		delay = pTmr->timeRemaining ();
-#       ifdef DEBUG
-	        printf ("delay for %f sec for %s\n", delay, pTmr->name () );
-#       endif
-	}
-	else {
-		//
-		// no timer in the queue - return a long delay - 30 min
-		//
-		delay = 30u * epicsTime::secPerMin;
-	}
-
-	return delay; // seconds
-}
-
-//
-// osiTimerQueue::process()
-//
-void osiTimerQueue::process ()
-{
-    if ( this->terminateFlag ) {
-        this->privateProcess ();
-    }
-}
-
-void osiTimerQueue::privateProcess ()
-{
-	epicsTime cur ( epicsTime::getCurrent () );
-	osiTimer *pTmr;
-	
-    this->mutex.lock ();
-
-	// no recursion
-	if (this->inProcess) {
-        this->mutex.unlock ();
-		return;
-	}
-	this->inProcess = true;
-	
-
-	tsDLIterBD <osiTimer> iter = this->timerLists[osiTimer::statePending].firstIter ();
-	while ( iter.valid () ) {	
-		if ( iter->exp > cur ) {
-			break;
-		}
-		tsDLIterBD <osiTimer> tmp = iter;
-		++tmp;
-		this->timerLists[osiTimer::statePending].remove(*iter);
-		iter->curState = osiTimer::stateExpired;
-		this->timerLists[osiTimer::stateExpired].add(*iter);
-		iter = tmp;
-	}
-	
-	//
-	// I am careful to prevent problems if they access the
-	// above list while in an "expire()" call back
-	//
-	while ( ( pTmr = this->timerLists[osiTimer::stateExpired].get () ) ) {
-		
-		pTmr->curState = osiTimer::stateIdle;
-		this->timerLists[osiTimer::stateIdle].add (*pTmr);
-
-		//
-		// Tag current tmr so that we
-		// can detect if it was deleted
-		// during the expire call back
-		//
-		this->pExpireTmr = pTmr;
-
-        //
-        // remove lock while calling their callback
-        //
-        this->mutex.unlock ();
-
-#ifdef DEBUG
-		double diff = cur-pTmr->exp;
-		printf ("expired %lx for \"%s\" with error %f\n", 
-			(unsigned long)pTmr, pTmr->name(), diff);
-#endif
-		
-		pTmr->expire();
-
-        this-> mutex.lock();
-
-		if ( this->pExpireTmr == pTmr ) {
-			if ( pTmr->again () ) {
-                this->timerLists[osiTimer::stateIdle].remove (*pTmr);
-				pTmr->arm (pTmr->delay());
-			}
-			else {
-				pTmr->destroy ();
-			}
-		}
-		else {
-			//
-			// no recursive calls  to process allowed
-			//
-			assert (this->pExpireTmr == 0);
-		}
-	}
-	this->inProcess = false;
-
-    this->mutex.unlock();
-}
-
-//
-// osiTimerQueue::show() const
-//
-void osiTimerQueue::show(unsigned level) const
-{
-    epicsAutoMutex locker ( this->mutex );
-	printf("osiTimerQueue with %u items pending and %u items expired\n",
-		this->timerLists[osiTimer::statePending].count(), 
-        this->timerLists[osiTimer::stateExpired].count());
-    tsDLIterConstBD <osiTimer> iter = this->timerLists[osiTimer::statePending].firstIter ();
-	while ( iter.valid () ) {	
-		iter->show(level);
-		++iter;
-	}
-}
-
-extern "C" epicsShareFunc osiTimerQueueId epicsShareAPI osiTimerQueueCreate ( unsigned managerThreadPriority )
-{
-    return (osiTimerQueueId) new osiTimerQueue ( osiTimerQueue::mtsCreateManagerThread, managerThreadPriority );
-}
-
-class osiTimerForC : public osiTimer {
-	epicsShareFunc virtual void expire();
-	epicsShareFunc virtual void destroy();
-	epicsShareFunc virtual bool again() const;
-	epicsShareFunc virtual double delay() const;
-	epicsShareFunc virtual void show (unsigned level) const;
-    const osiTimerJumpTable &jt;
-    void * pPrivate;
-public:
-    osiTimerForC (const osiTimerJumpTable &jtIn, osiTimerQueue &queue, void *pPrivateIn);
-};
-
-osiTimerForC::osiTimerForC (const osiTimerJumpTable &jtIn, osiTimerQueue &queue, void *pPrivateIn) :
-    osiTimer (queue), jt (jtIn), pPrivate (pPrivateIn) {}
-
-void osiTimerForC::expire ()
-{
-    (*this->jt.expire) (this->pPrivate);
-}
-
-void osiTimerForC::destroy ()
-{
-    (*this->jt.destroy) (this->pPrivate);
-}
-
-bool osiTimerForC::again () const
-{
-    return (*this->jt.again) (this->pPrivate) ? true : false ;
-}
-
-double osiTimerForC::delay () const 
-{
-    return (*this->jt.delay) (this->pPrivate);
-}
-
-void osiTimerForC::show (unsigned level) const 
-{
-    (*this->jt.show) (this->pPrivate, level);
-}
-
-extern "C" epicsShareFunc osiTimerId epicsShareAPI osiTimerCreate (const osiTimerJumpTable *pjtIn, osiTimerQueueId queueIdIn, void *pPrivateIn)
-{
-    assert (pjtIn);
-    assert (queueIdIn);
-    return (osiTimerId) new osiTimerForC (*pjtIn, *static_cast<osiTimerQueue *>(queueIdIn), pPrivateIn);
-}
-
-extern "C" epicsShareFunc void epicsShareAPI osiTimerArm  (osiTimerId tmrIdIn, double delay)
-{
-    osiTimerForC *pTmr = static_cast<osiTimerForC *>(tmrIdIn);
-    assert (pTmr);
-    pTmr->reschedule (delay);
-}
-
-extern "C" epicsShareFunc void epicsShareAPI osiTimerCancel (osiTimerId tmrIdIn)
-{
-    osiTimerForC *pTmr = static_cast<osiTimerForC *>(tmrIdIn);
-    assert (pTmr);
-    pTmr->cancel ();
-}
-
-extern "C" epicsShareFunc double epicsShareAPI osiTimerTimeRemaining (osiTimerId idIn)
-{
-    osiTimerForC *pTmr = static_cast<osiTimerForC *> (idIn);
-    assert (pTmr);
-    return pTmr->timeRemaining ();
-}
-
-extern "C" epicsShareFunc epicsTimeStamp epicsShareAPI osiTimerExpirationDate (osiTimerId idIn)
-{
-    osiTimerForC *pTmr = static_cast<osiTimerForC *> (idIn);
-    assert (pTmr);
-    return pTmr->expirationDate ();
-}
diff --git a/src/libCom/timer/osiTimer.h b/src/libCom/timer/osiTimer.h
deleted file mode 100644
index 375bb8b09..000000000
--- a/src/libCom/timer/osiTimer.h
+++ /dev/null
@@ -1,253 +0,0 @@
-/*
- *      $Id$
- *
- *      Author  Jeffrey O. Hill
- *              johill@lanl.gov
- *              505 665 1831
- *
- *      Experimental Physics and Industrial Control System (EPICS)
- *
- *      Copyright 1991, the Regents of the University of California,
- *      and the University of Chicago Board of Governors.
- *
- *      This software was produced under  U.S. Government contracts:
- *      (W-7405-ENG-36) at the Los Alamos National Laboratory,
- *      and (W-31-109-ENG-38) at Argonne National Laboratory.
- *
- *      Initial development by:
- *              The Controls and Automation Group (AT-8)
- *              Ground Test Accelerator
- *              Accelerator Technology Division
- *              Los Alamos National Laboratory
- *
- *      Co-developed with
- *              The Controls and Computing Group
- *              Accelerator Systems Division
- *              Advanced Photon Source
- *              Argonne National Laboratory
- *
- */
-
-#ifndef osiTimerHInclude
-#define osiTimerHInclude
-
-#include "shareLib.h" /* reset share lib defines */
-#include "epicsThread.h"
-#include "epicsTime.h"
-
-#ifdef __cplusplus
-
-#include "epicsTime.h"
-#include "tsDLList.h"
-#include "epicsMutex.h"
-#include "epicsEvent.h"
-
-class osiTimerQueue;
-
-/*
- * osiTimer
- */
-class osiTimer : public tsDLNode <osiTimer> {
-public:
-    class noDelaySpecified {}; /* exception */
-    class noMemory {}; /* exception */
-
-    /*
-     * Create an active timer that will expire delay seconds after it is created
-     * or create an inactive timer respectively. 
-     *
-     * ** Warning ** default timer queue has no manager thread and is typically
-     * processed by the file descriptor manager
-     */
-    epicsShareFunc osiTimer ( double delay, osiTimerQueue & queueIn );
-    epicsShareFunc osiTimer ( double delay );
-
-    /*
-     * Create an inactive timer
-     *
-     * ** Warning ** default timer queue has no manager thread and is typically
-     * processed by the file descriptor manager
-     */
-    epicsShareFunc osiTimer ( osiTimerQueue & queueIn );
-    epicsShareFunc osiTimer ();
-
-    /*
-     * change the timers expiration to newDelay
-     * seconds after when reschedule() is called
-     */ 
-    epicsShareFunc void reschedule (double newDelay);
-
-    /*
-     * change the timers expiration to this->delay()
-     * seconds after when reschedule() is called
-     */ 
-    epicsShareFunc void reschedule ();
-
-    /*
-     * Start the timer with delay newDelay if inactive.
-     */ 
-    epicsShareFunc void activate ( double newDelay );
-
-    /*
-     * Start the timer with delay this->delay() if inactive.
-     */ 
-    epicsShareFunc void activate ();
-
-    /*
-     * inactivate the timer and call the virtual destroy()
-     * member function
-     */
-    epicsShareFunc void cancel ();
-
-    /*
-     * return the number of seconds remaining before
-     * this osiTimer will expire or the expiration date
-     * respectively
-     */
-    epicsShareFunc double timeRemaining () const; /* returns seconds, but inefficent */
-    epicsShareFunc epicsTime expirationDate () const; /* efficent */
-
-    /*
-     * called when the osiTimer expires
-     */
-    epicsShareFunc virtual void expire () = 0;
-
-    /*
-     * called if 
-     * 1) osiTimer exists and the osiTimerQueue is deleted
-     * 2) when the osiTimer expires and again() returns false
-     *
-     * osiTimer::destroy() does a "delete this"
-     *
-     * if the derived class replaces this function then it
-     * is taking responsibility for freeing (deleting)
-     * timer resources when they are nolonger needed.
-     */
-    epicsShareFunc virtual void destroy ();
-
-    /*
-     * returning true indicates that the
-     * osiTimer should be rearmed with delay
-     * "delay()" when it expires
-     *
-     * the defaut osiTimer::again() returns false
-     * (run the osiTimer once only)
-     */
-    epicsShareFunc virtual bool again () const;
-
-    /*
-     * returns the delay prior to expire
-     * for subsequent iterations (if "again()"
-     * returns true)
-     *
-     * the default osiTimer::delay() throws the 
-     * exception type noDelaySpecified, but it will 
-     * not be called unless the again() virtual 
-     * function returns true.
-     */
-    epicsShareFunc virtual double delay () const;
-
-    epicsShareFunc virtual void show (unsigned level) const;
-
-    /*
-     * for diagnostics
-     */
-    epicsShareFunc virtual const char *name () const;
-
-    epicsShareFunc virtual ~osiTimer ();
-
-private:
-    friend class osiTimerQueue;
-    enum state {statePending, stateExpired, stateIdle, 
-        numberOfTimerLists, stateLimbo};
-
-    epicsTime exp; /* experation time */
-    state curState; /* current state */
-    osiTimerQueue &queue; /* pointer to current timer queue */
-
-    /*
-     * place osiTimer in the pending queue
-     */
-    void arm (double initialDelay);
-};
-
-/*
- * osiTimerQueue
- */
-class osiTimerQueue {
-friend class osiTimer;
-friend class osiTimerThread;
-public:
-    enum managerThreadSelect { 
-        mtsNoManagerThread, // you must call the process method (or the fdManager) to expire timers
-        mtsCreateManagerThread // manager thread expires timers asnychronously
-    };
-    epicsShareFunc osiTimerQueue ( managerThreadSelect mts, 
-        unsigned managerThreadPriority = epicsThreadPriorityMin );
-    epicsShareFunc virtual ~osiTimerQueue();
-    epicsShareFunc double delayToFirstExpire () const; /* returns seconds */
-    epicsShareFunc void process ();
-    epicsShareFunc void show (unsigned level) const;
-private:
-    mutable epicsMutex mutex;
-    epicsEvent rescheduleEvent;
-    epicsEvent exitEvent;
-    tsDLList <osiTimer> timerLists [osiTimer::numberOfTimerLists];
-    osiTimer *pExpireTmr;
-    class osiTimerThread *pMgrThread;
-    unsigned mgrThreadPriority;
-    bool inProcess;
-    bool terminateFlag;
-    bool exitFlag;
-
-    void install (osiTimer &tmr, double delay);
-    void privateProcess ();
-    void terminateManagerThread ();
-};
-
-/*
- * ** Warning ** 
- * the default timer queue has no manager thread and is typically
- * processed by the file descriptor manager
- */
-epicsShareExtern osiTimerQueue osiDefaultTimerQueue;
-
-inline epicsTime osiTimer::expirationDate () const
-{
-    return this->exp;
-}
-
-#endif /* ifdef __cplusplus */
-
-#ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-
-/*
- * osiTimerJumpTable
- */
-typedef struct osiTimerJumpTable {
-    void (*expire) (void *pPrivate); /* called when timer expires */
-    void (*destroy) (void *pPrivate); /* called after expire() when again() is false */
-    int (*again) (void *pPrivate); /* rearm after expire when again() is true */
-    double (*delay) (void *pPrivate); /* rearm delay */
-    void (*show) (void *pPrivate, unsigned level); /* diagnostic */
-}osiTimerJumpTable;
-
-typedef void * osiTimerQueueId;
-/* see epicsThread.h for the range of priorities allowed here */
-epicsShareFunc osiTimerQueueId epicsShareAPI osiTimerQueueCreate (unsigned managerThreadPriority);
-
-typedef void * osiTimerId;
-epicsShareFunc osiTimerId epicsShareAPI osiTimerCreate (const osiTimerJumpTable *, osiTimerQueueId, void *pPrivate);
-epicsShareFunc void epicsShareAPI osiTimerArm  (osiTimerId, double delay);
-epicsShareFunc void epicsShareAPI osiTimerCancel (osiTimerId);
-epicsShareFunc double epicsShareAPI osiTimerTimeRemaining (osiTimerId);
-epicsShareFunc epicsTimeStamp epicsShareAPI osiTimerExpirationDate (osiTimerId);
-
-#ifdef __cplusplus
-}
-#endif /* __cplusplus */
-
-#endif /* osiTimerHInclude */
-
diff --git a/src/libCom/timer/timer.cpp b/src/libCom/timer/timer.cpp
index 2335eaff0..6e3016292 100644
--- a/src/libCom/timer/timer.cpp
+++ b/src/libCom/timer/timer.cpp
@@ -37,8 +37,8 @@ epicsMutex timer::freeListMutex;
 
 epicsTimer::~epicsTimer () {}
 
-timer::timer ( epicsTimerNotify &notifyIn, timerQueue &queueIn ) :
-    curState ( stateLimbo ), notify ( notifyIn ), queue ( queueIn )
+timer::timer ( timerQueue &queueIn ) :
+    curState ( stateLimbo ), pNotify ( 0 ), queue ( queueIn )
 {
 }
 
@@ -47,21 +47,21 @@ timer::~timer()
     this->cancel ();
 }
 
-void timer::start ( double delaySeconds )
+void timer::start ( epicsTimerNotify & notify, double delaySeconds )
 {
-    this->start ( epicsTime::getCurrent () + delaySeconds );
+    this->start ( notify, epicsTime::getCurrent () + delaySeconds );
 }
 
-void timer::start ( const epicsTime & expire )
+void timer::start ( epicsTimerNotify & notify, const epicsTime & expire )
 {
     epicsAutoMutex locker ( this->queue.mutex );
-    this->privateStart ( expire );
+    this->privateCancel ();
+    this->privateStart ( notify, expire );
 }
 
-void timer::privateStart ( const epicsTime & expire )
+void timer::privateStart ( epicsTimerNotify & notify, const epicsTime & expire )
 {
-    this->privateCancel ();
-
+    this->pNotify = & notify;
     this->exp = expire;
 
 #   ifdef DEBUG
@@ -100,12 +100,12 @@ void timer::privateStart ( const epicsTime & expire )
 
     this->curState = timer::statePending;
     
-#   ifdef DEBUG 
+#   if defined(DEBUG) && 0
         this->show ( 10u );
         this->queue.show ( 10u );
 #   endif
 
-    debugPrintf ( ("Arm of \"%s\" with delay %f at %p preempting %u\n", 
+    debugPrintf ( ("Start of \"%s\" with delay %f at %p preempting %u\n", 
         typeid ( this->notify ).name (), 
         expire - epicsTime::getCurrent (), 
         this, preemptCount ) );
@@ -113,49 +113,68 @@ void timer::privateStart ( const epicsTime & expire )
 
 void timer::cancel ()
 {
-    {
-        epicsAutoMutex locker ( this->queue.mutex );
-        this->privateCancel ();
-        // dont wait if this was called indirectly by expire ()
-        if ( this->queue.pExpireTmr == this && 
-            this->queue.processThread != epicsThreadGetIdSelf() ) {
-            this->queue.cancelPending = true;
-        }
-    }
-
-    // make certain timer expire() does not run after cancel () returns,
-    // but dont require that lock is applied while calling expire()
-    if ( this->queue.cancelPending ) {
-        while ( this->queue.cancelPending ) {
-            this->queue.cancelBlockingEvent.wait ();
-        }
-        // in case other threads are waiting
-        this->queue.cancelBlockingEvent.signal ();
-    }
+    epicsAutoMutex locker ( this->queue.mutex );
+    this->privateCancel ();
 }
 
 void timer::privateCancel ()
 {
-    if ( this->curState == statePending ) {
-        this->queue.timerList.remove ( *this );
-        this->curState = stateLimbo;
+    while ( true ) {
+        if ( this->curState == statePending ) {
+            this->queue.timerList.remove ( *this );
+            this->curState = stateLimbo;
+            this->pNotify = 0;
+        }
+        // dont wait if this was called indirectly by expire ()
+        if ( this->queue.pExpireTmr == this && 
+            this->queue.processThread != epicsThreadGetIdSelf() ) {
+            this->queue.cancelPending = true;
+            // make certain timer expire() does not run after cancel () returns,
+            // but dont require that lock is applied while calling expire()
+            {
+                epicsAutoMutexRelease autoRelease ( this->queue.mutex );
+                while ( this->queue.cancelPending ) {
+                    this->queue.cancelBlockingEvent.wait ();
+                }
+                // in case other threads are waiting
+                this->queue.cancelBlockingEvent.signal ();
+            }
+        }
+        else {
+            return;
+        }
     }
 }
 
-double timer::getExpireDelay () const
+epicsTimer::expireInfo timer::getExpireInfo () const
 {
     epicsAutoMutex locker ( this->queue.mutex );
-    return this->privateDelayToFirstExpire ();
+    if ( this->curState == statePending || this->queue.pExpireTmr == this ) {
+        return expireInfo ( true, this->exp );
+    }
+    else {
+        return expireInfo ( false, epicsTime() );
+    }
 }
 
 void timer::show ( unsigned int level ) const
 {
-    double delay = this->getExpireDelay ();
-    printf ( "%s, state = %s, delay to expire = %g\n", 
-        typeid ( this->notify ).name (), 
-        this->curState == statePending ? "pending" : "limbo",
+    epicsAutoMutex locker ( this->queue.mutex );
+    const char * pName = "<no notify attached>";
+    if ( this->pNotify ) {
+        pName = typeid ( *this->pNotify ).name ();
+    }
+    double delay;
+    if ( this->curState == statePending ) {
+        delay = this->exp - epicsTime::getCurrent();
+    }
+    else {
+        delay = -DBL_MAX;
+    }
+    printf ( "%s, state = %s, delay = %f\n",
+        pName, this->curState == statePending ? "pending" : "limbo",
         delay );
-    if ( level >= 1u ) {
-        this->notify.show ( level - 1u );
+    if ( level >= 1u && this->pNotify ) {
+        this->pNotify->show ( level - 1u );
     }
 }
diff --git a/src/libCom/timer/timerPrivate.h b/src/libCom/timer/timerPrivate.h
index 6b328cc01..900c1d1eb 100644
--- a/src/libCom/timer/timerPrivate.h
+++ b/src/libCom/timer/timerPrivate.h
@@ -43,11 +43,11 @@
 
 class timer : public epicsTimer, public tsDLNode < timer > {
 public:
-    timer ( epicsTimerNotify &, class timerQueue & );
-    void start ( const epicsTime & );
-    void start ( double delaySeconds );
+    timer ( class timerQueue & );
+    void start ( class epicsTimerNotify &, const epicsTime & );
+    void start ( class epicsTimerNotify &, double delaySeconds );
     void cancel ();
-    double getExpireDelay () const;
+    expireInfo getExpireInfo () const;
     void show ( unsigned int level ) const;
     void * operator new ( size_t size );
     void operator delete ( void *pCadaver, size_t size );
@@ -58,11 +58,10 @@ private:
     enum state { statePending = 45, stateLimbo = 78 };
     epicsTime exp; // experation time 
     state curState; // current state 
-    epicsTimerNotify &notify; // callback
+    epicsTimerNotify *pNotify; // callback
     timerQueue &queue;
-    void privateStart ( const epicsTime & );
+    void privateStart ( epicsTimerNotify & notify, const epicsTime & );
     void privateCancel ();
-    double privateDelayToFirstExpire () const;
     static tsFreeList < class timer, 0x20 > freeList;
     static epicsMutex freeListMutex;
     friend class timerQueue;
@@ -72,8 +71,7 @@ class timerQueue {
 public:
     timerQueue ( epicsTimerQueueNotify &notify );
     ~timerQueue ();
-    void process ();
-    double delayToFirstExpire () const;
+    double process ( const epicsTime & currentTime );
     void show ( unsigned int level ) const;
 private:
     mutable epicsMutex mutex;
@@ -102,7 +100,7 @@ class timerQueueActive : public epicsTimerQueueActive,
 public:
     timerQueueActive ( bool okToShare, unsigned priority );
     ~timerQueueActive () = 0;
-    epicsTimer & createTimer ( epicsTimerNotify & );
+    epicsTimer & createTimer ();
     void show ( unsigned int level ) const;
     bool sharingOK () const;
     int threadPriority () const;
@@ -149,9 +147,8 @@ extern timerQueueActiveMgr queueMgr;
 class timerQueuePassive : public epicsTimerQueuePassive {
 public:
     timerQueuePassive ( epicsTimerQueueNotify & );
-    epicsTimer & createTimer ( epicsTimerNotify & );
-    void process ();
-    double getNextExpireDelay () const;
+    epicsTimer & createTimer ();
+    double process ( const epicsTime & currentTime );
     void show ( unsigned int level ) const;
     void release ();
     timerQueue & getTimerQueue ();
@@ -177,20 +174,6 @@ inline void timer::operator delete ( void *pCadaver, size_t size )
     timer::freeList.release ( pCadaver, size );
 }
 
-inline double timer::privateDelayToFirstExpire () const
-{
-    if ( this->curState == statePending ) {
-        double delay = this->exp - epicsTime::getCurrent ();
-        if ( delay < 0.0 ) {
-            delay = 0.0;
-        }
-        return delay;
-    }
-    else {
-        return -DBL_MAX;
-    }
-}
-
 inline bool timerQueueActive::sharingOK () const
 {
     return this->okToShare;
diff --git a/src/libCom/timer/timerQueue.cpp b/src/libCom/timer/timerQueue.cpp
index 7ab8c28fb..a12684cee 100644
--- a/src/libCom/timer/timerQueue.cpp
+++ b/src/libCom/timer/timerQueue.cpp
@@ -48,39 +48,35 @@ timerQueue::~timerQueue ()
     }
 }
 
-double timerQueue::delayToFirstExpire () const
-{
-    epicsAutoMutex locker ( this->mutex );
-    timer *pTmr = this->timerList.first ();
-    if ( pTmr ) {
-        return pTmr->privateDelayToFirstExpire ();
-    }
-    else {
-        return DBL_MAX;
-    }
-}
-
-void timerQueue::process ()
-{
-    epicsTime cur ( epicsTime::getCurrent () );
-  
+double timerQueue::process ( const epicsTime & currentTime )
+{  
     {
         epicsAutoMutex locker ( this->mutex );
 
         if ( this->pExpireTmr ) {
             // if some other thread is processing the queue
             // (or if this is a recursive call)
-            return; 
+            timer *pTmr = this->timerList.first ();
+            if ( pTmr ) {
+                double delay = pTmr->exp - currentTime;
+                if ( delay < 0.0 ) {
+                    delay = 0.0;
+                }
+                return delay;
+            }
+            else {
+                return DBL_MAX;
+            }
         }
 
+        //
+        // Tag current epired tmr so that we can detect if call back
+        // is in progress when canceling the timer.
+        //
         this->pExpireTmr = this->timerList.first ();
         if ( this->pExpireTmr ) {
-            if ( cur >= this->pExpireTmr->exp ) {
+            if ( currentTime >= this->pExpireTmr->exp ) {
                 this->timerList.remove ( *this->pExpireTmr ); 
-                //
-                // Tag current epired tmr so that we can detect if call back
-                // is in progress when canceling the timer.
-                //
                 this->pExpireTmr->curState = timer::stateLimbo;
                 this->processThread = epicsThreadGetIdSelf ();
 #               ifdef DEBUG
@@ -88,13 +84,14 @@ void timerQueue::process ()
 #               endif 
             }
             else {
+                double delay = this->pExpireTmr->exp - currentTime;
                 this->pExpireTmr = 0;
-                debugPrintf ( ( "no activity process %f to next\n", this->pExpireTmr->exp - cur ) );
-                return;
+                debugPrintf ( ( "no activity process %f to next\n", delay ) );
+                return delay;
             }
         }
         else {
-            return;
+            return DBL_MAX;
         }
     }
 
@@ -106,9 +103,10 @@ void timerQueue::process ()
  
         debugPrintf ( ( "%5u expired \"%s\" with error %f sec\n", 
             N++, typeid ( this->pExpireTmr->notify ).name (), 
-            cur - this->pExpireTmr->exp ) );
+            currentTime - this->pExpireTmr->exp ) );
 
-        epicsTimerNotify::expireStatus expStat = this->pExpireTmr->notify.expire ();
+        epicsTimerNotify::expireStatus expStat = 
+            this->pExpireTmr->pNotify->expire ( currentTime );
 
         epicsAutoMutex locker ( this->mutex );
 
@@ -120,15 +118,21 @@ void timerQueue::process ()
             // cancel() waits for this
             this->cancelPending = false;
             this->cancelBlockingEvent.signal ();
+            this->pExpireTmr->pNotify = 0;
         }
         // restart as nec
         else if ( expStat.restart() ) {
-            this->pExpireTmr->privateStart ( cur + expStat.expirationDelay() );
+            this->pExpireTmr->privateStart ( 
+                *this->pExpireTmr->pNotify, 
+                currentTime + expStat.expirationDelay() );
+        }
+        else {
+            this->pExpireTmr->pNotify = 0;
         }
 
         this->pExpireTmr = this->timerList.first ();
         if ( this->pExpireTmr ) {
-            if ( cur >= this->pExpireTmr->exp ) {
+            if ( currentTime >= this->pExpireTmr->exp ) {
                 this->timerList.remove ( *this->pExpireTmr ); 
                 this->pExpireTmr->curState = timer::stateLimbo;
 #               ifdef DEBUG
@@ -136,14 +140,15 @@ void timerQueue::process ()
 #               endif 
             }
             else {
+                double delay = this->pExpireTmr->exp - currentTime;
                 this->pExpireTmr = 0;
                 this->processThread = 0;
-                return;
+                return delay;
             }
         }
         else {
             this->processThread = 0;
-            return;
+            return DBL_MAX;
         }
     }
 }
diff --git a/src/libCom/timer/timerQueueActive.cpp b/src/libCom/timer/timerQueueActive.cpp
index dbabafe98..f72ea1c8e 100644
--- a/src/libCom/timer/timerQueueActive.cpp
+++ b/src/libCom/timer/timerQueueActive.cpp
@@ -63,22 +63,17 @@ void timerQueueActive::run ()
 {
     this->exitFlag = false;
     while ( ! this->terminateFlag ) {
-        double delay = this->queue.delayToFirstExpire ();
-        if ( delay <= 0.0 ) {
-            this->queue.process ();
-        }
-        else {
-            debugPrintf ( ( "timer thread sleeping for %g sec (max)\n", delay ) );
-            this->rescheduleEvent.wait ( delay );
-        }
+        double delay = this->queue.process ( epicsTime::getCurrent() );
+        debugPrintf ( ( "timer thread sleeping for %g sec (max)\n", delay ) );
+        this->rescheduleEvent.wait ( delay );
     }
     this->exitFlag = true; 
     this->exitEvent.signal (); // no access to queue after exitEvent signal
 }
 
-epicsTimer & timerQueueActive::createTimer ( epicsTimerNotify & notify )
+epicsTimer & timerQueueActive::createTimer ()
 {
-    timer *pTmr = new timer ( notify, this->queue );
+    timer *pTmr = new timer ( this->queue );
     if ( ! pTmr ) {
         throwWithLocation ( timer::noMemory () );
     }
diff --git a/src/libCom/timer/timerQueuePassive.cpp b/src/libCom/timer/timerQueuePassive.cpp
index dec565992..87a63d40c 100644
--- a/src/libCom/timer/timerQueuePassive.cpp
+++ b/src/libCom/timer/timerQueuePassive.cpp
@@ -50,23 +50,18 @@ timerQueuePassive::timerQueuePassive ( epicsTimerQueueNotify &notifyIn ) :
 
 timerQueuePassive::~timerQueuePassive () {}
 
-epicsTimer & timerQueuePassive::createTimer ( epicsTimerNotify & notifyIn )
+epicsTimer & timerQueuePassive::createTimer ()
 {
-    timer *pTmr = new timer ( notifyIn, this->queue );
+    timer *pTmr = new timer ( this->queue );
     if ( ! pTmr ) {
         throwWithLocation ( timer::noMemory () );
     }
     return *pTmr;
 }
 
-void timerQueuePassive::process ()
+double timerQueuePassive::process ( const epicsTime & currentTime )
 {
-    this->queue.process ();
-}
-
-double timerQueuePassive::getNextExpireDelay () const
-{
-    return this->queue.delayToFirstExpire ();
+    return this->queue.process ( currentTime );
 }
 
 void timerQueuePassive::show ( unsigned int level ) const