diff --git a/mps/code/locus.c b/mps/code/locus.c
index 5a6cb9b8395..140e1d9103c 100644
--- a/mps/code/locus.c
+++ b/mps/code/locus.c
@@ -107,7 +107,7 @@ Bool GenDescCheck(GenDesc gen)
 {
   CHECKS(GenDesc, gen);
   /* nothing to check for zones */
-  /* nothing to check for capacity */
+  CHECKL(gen->capacity > 0);
   CHECKL(gen->mortality >= 0.0);
   CHECKL(gen->mortality <= 1.0);
   CHECKD_NOSIG(Ring, &gen->locusRing);
@@ -123,6 +123,7 @@ static Bool GenParamCheck(GenParamStruct *params)
 {
   CHECKL(params != NULL);
   CHECKL(params->capacity > 0);
+  CHECKL(params->capacity <= SizeMAX / 1024);
   CHECKL(params->mortality >= 0.0);
   CHECKL(params->mortality <= 1.0);
   return TRUE;
@@ -139,7 +140,7 @@ static void GenDescInit(GenDesc gen, GenParamStruct *params)
   AVER(GenParamCheck(params));
 
   gen->zones = ZoneSetEMPTY;
-  gen->capacity = params->capacity;
+  gen->capacity = params->capacity * 1024;
   gen->mortality = params->mortality;
   RingInit(&gen->locusRing);
   RingInit(&gen->segRing);
@@ -162,7 +163,7 @@ static void GenDescFinish(GenDesc gen)
   gen->sig = SigInvalid;
   RingFinish(&gen->locusRing);
   RingFinish(&gen->segRing);
-  AVER(gen->activeTraces == TraceSetEMPTY);
+  AVER(gen->activeTraces == TraceSetEMPTY); /* <design/check/#.common> */
   for (ti = 0; ti < TraceLIMIT; ++ti)
     RingFinish(&gen->trace[ti].traceRing);
 }
@@ -465,7 +466,7 @@ double ChainDeferral(Chain chain)
     GenDesc gen = &chain->gens[i];
     if (gen->activeTraces != TraceSetEMPTY)
       return DBL_MAX;
-    genTime = gen->capacity * 1024.0 - (double)GenDescNewSize(&chain->gens[i]);
+    genTime = (double)gen->capacity - (double)GenDescNewSize(&chain->gens[i]);
     if (genTime < time)
       time = genTime;
   }
@@ -864,7 +865,7 @@ void LocusInit(Arena arena)
 
   AVER(arena != NULL); /* not initialized yet. */
  
-  params.capacity = 1; /* unused */
+  params.capacity = 1; /* unused since top generation is not on any chain */
   params.mortality = 0.5;
  
   GenDescInit(&arena->topGen, &params);
diff --git a/mps/code/locus.h b/mps/code/locus.h
index 5525f242457..7c71a714dd1 100644
--- a/mps/code/locus.h
+++ b/mps/code/locus.h
@@ -43,7 +43,7 @@ typedef struct GenDescStruct *GenDesc;
 typedef struct GenDescStruct {
   Sig sig;
   ZoneSet zones;        /* zoneset for this generation */
-  Size capacity;        /* capacity in kB */
+  Size capacity;        /* capacity in bytes */
   double mortality;     /* predicted mortality */
   RingStruct locusRing; /* Ring of all PoolGen's in this GenDesc (locus) */
   RingStruct segRing; /* Ring of GCSegs in this generation */
diff --git a/mps/code/mpmst.h b/mps/code/mpmst.h
index ea6054bcdce..f68a7ce865f 100644
--- a/mps/code/mpmst.h
+++ b/mps/code/mpmst.h
@@ -434,7 +434,7 @@ typedef struct TraceStruct {
   Bool firstStretch;            /* in first stretch of band (see accessor) */
   SegFixMethod fix;             /* fix method to apply to references */
   void *fixClosure;             /* see .ss.fix-closure */
-  RingStruct genRing;           /* ring of generations condemned by trace */
+  RingStruct genRing;           /* ring of generations condemned for trace */
   STATISTIC_DECL(Size preTraceArenaReserved) /* ArenaReserved before this trace */
   Size condemned;               /* condemned bytes */
   Size notCondemned;            /* collectable but not condemned */
diff --git a/mps/code/policy.c b/mps/code/policy.c
index eabb43d2e5d..34b5e3a9b54 100644
--- a/mps/code/policy.c
+++ b/mps/code/policy.c
@@ -229,7 +229,7 @@ static Res policyCondemnChain(double *mortalityReturn, Chain chain, Trace trace)
     -- topCondemnedGen;
     gen = &chain->gens[topCondemnedGen];
     AVERT(GenDesc, gen);
-    if (GenDescNewSize(gen) >= gen->capacity * (Size)1024)
+    if (GenDescNewSize(gen) >= gen->capacity)
       break;
   }
 
diff --git a/mps/manual/source/topic/error.rst b/mps/manual/source/topic/error.rst
index 892a26b9bcf..e3df2352d7e 100644
--- a/mps/manual/source/topic/error.rst
+++ b/mps/manual/source/topic/error.rst
@@ -324,7 +324,7 @@ this documentation.
     :term:`stepper functions`.
 
 
-``locus.c: chain->activeTraces == TraceSetEMPTY``
+``locus.c: gen->activeTraces == TraceSetEMPTY``
 
     The client program called :c:func:`mps_chain_destroy`, but there
     was a garbage collection in progress on that chain. Park the arena