diff --git a/mps/src/mpmst.h b/mps/src/mpmst.h
index e726c5502c4..ca5ecd3ccf7 100644
--- a/mps/src/mpmst.h
+++ b/mps/src/mpmst.h
@@ -1,6 +1,6 @@
 /* impl.h.mpmst: MEMORY POOL MANAGER DATA STRUCTURES
  *
- * $HopeName: MMsrc!mpmst.h(trunk.91) $
+ * $HopeName: MMsrc!mpmst.h(trunk.92) $
  * Copyright (C) 2001 Harlequin Limited.  All rights reserved.
  *
  * .design: This header file crosses module boundaries.  The relevant
@@ -280,12 +280,12 @@ typedef struct SegStruct {      /* segment structure */
   RingStruct poolRing;          /* link in list of segs in pool */
   Addr limit;                   /* limit of segment */
   unsigned depth : SHIELD_DEPTH_WIDTH; /* see impl.c.shield.def.depth */
-  AccessSet pm : AccessMAX;     /* protection mode, impl.c.shield */
-  AccessSet sm : AccessMAX;     /* shield mode, impl.c.shield */
-  TraceSet grey : TRACE_MAX;    /* traces for which seg is grey */
-  TraceSet white : TRACE_MAX;   /* traces for which seg is white */
-  TraceSet nailed : TRACE_MAX;  /* traces for which seg has nailed objects */
-  RankSet rankSet : RankMAX;    /* ranks of references in this seg */
+  AccessSet pm : AccessSetWIDTH; /* protection mode, impl.c.shield */
+  AccessSet sm : AccessSetWIDTH; /* shield mode, impl.c.shield */
+  TraceSet grey : TraceLIMIT;   /* traces for which seg is grey */
+  TraceSet white : TraceLIMIT;  /* traces for which seg is white */
+  TraceSet nailed : TraceLIMIT; /* traces for which seg has nailed objects */
+  RankSet rankSet : RankLIMIT;  /* ranks of references in this seg */
 } SegStruct;
 
 
@@ -741,9 +741,9 @@ typedef struct ArenaStruct {
   /* trace fields (impl.c.trace) */
   TraceSet busyTraces;          /* set of running traces */
   TraceSet flippedTraces;       /* set of running and flipped traces */
-  TraceStruct trace[TRACE_MAX]; /* trace structures.  See
+  TraceStruct trace[TraceLIMIT]; /* trace structures.  See
                                    design.mps.trace.intance.limit */
-  RingStruct greyRing[RankMAX]; /* ring of grey segments at each rank */
+  RingStruct greyRing[RankLIMIT]; /* ring of grey segments at each rank */
   STATISTIC_DECL(Count writeBarrierHitCount); /* write barrier hits */
   Bool clamped;                 /* prevent background activity */
   RingStruct chainRing;         /* ring of chains */
diff --git a/mps/src/mpmtypes.h b/mps/src/mpmtypes.h
index 40946a19811..949c134c59a 100644
--- a/mps/src/mpmtypes.h
+++ b/mps/src/mpmtypes.h
@@ -1,6 +1,6 @@
 /* impl.h.mpmtypes: MEMORY POOL MANAGER TYPES
  *
- * $HopeName: MMsrc!mpmtypes.h(trunk.86) $
+ * $HopeName: MMsrc!mpmtypes.h(trunk.87) $
  * Copyright (C) 2001 Harlequin Limited.  All rights reserved.
  *
  * .design: design.mps.type
@@ -247,8 +247,7 @@ typedef Addr (*FormatClassMethod)(Addr object);
 /* MPS C Interface.  (See impl.h.mps.root-methods.) */
 
 typedef Res (*RootScanMethod)(ScanState ss, void *p, size_t s);
-typedef Res (*RootScanRegMethod)(ScanState ss, Thread thread, void *p, 
-                                 size_t s);
+typedef Res (*RootScanRegMethod)(ScanState ss, Thread thread, void *p, size_t s);
 
 
 /* CONSTANTS */
@@ -261,15 +260,15 @@ typedef Res (*RootScanRegMethod)(ScanState ss, Thread thread, void *p,
 #define AccessSetEMPTY  ((AccessSet)0) /* design.mps.type.access-set */
 #define AccessREAD      ((AccessSet)(1<<0))
 #define AccessWRITE     ((AccessSet)(1<<1))
-#define AccessMAX       ((Size)2)
+#define AccessSetWIDTH  (2)
 #define RefSetEMPTY     BS_EMPTY(RefSet)
 #define RefSetUNIV      BS_UNIV(RefSet)
 #define ZoneSetEMPTY    BS_EMPTY(ZoneSet)
 #define ZoneSetUNIV     BS_UNIV(ZoneSet)
 #define TraceSetEMPTY   BS_EMPTY(TraceSet)
-#define TraceSetUNIV    ((TraceSet)((1u<<TRACE_MAX)-1))
+#define TraceSetUNIV    ((TraceSet)((1u << TraceLIMIT) - 1))
 #define RankSetEMPTY    BS_EMPTY(RankSet)
-#define RankSetUNIV     ((RankSet)((1u<<RankMAX)-1))
+#define RankSetUNIV     ((RankSet)((1u << RankLIMIT) - 1))
 #define AttrFMT         ((Attr)(1<<0))  /* design.mps.type.attr */
 #define AttrSCAN        ((Attr)(1<<1))
 #define AttrPM_NO_READ  ((Attr)(1<<2))
@@ -320,8 +319,7 @@ enum {
 enum {
   BufferFrameVALID = 1,
   BufferFramePOP_PENDING,
-  BufferFrameDISABLED,
-  BufferFrameMAX
+  BufferFrameDISABLED
 };
 
 
@@ -334,7 +332,7 @@ enum {
   RankEXACT = 1,
   RankFINAL = 2,
   RankWEAK = 3,
-  RankMAX
+  RankLIMIT
 };
 
 
@@ -397,9 +395,9 @@ enum {
 /* .message.types: Keep in sync with impl.h.mps.message.types */
 
 enum {
-  MessageTypeFinalization,
+  MessageTypeFINALIZATION,
   MessageTypeGC,
-  MessageTypeMAX
+  MessageTypeLIMIT
 };