diff --git a/basis/calendar/calendar-tests.factor b/basis/calendar/calendar-tests.factor
index 3f52b4d2e7..5cfb042608 100644
--- a/basis/calendar/calendar-tests.factor
+++ b/basis/calendar/calendar-tests.factor
@@ -140,7 +140,6 @@ IN: calendar.tests
 [ +gt+ ] [ 2005 1 1 12 30 0 instant <timestamp>
         2004 1 1 13 30 0 instant <timestamp> <=> ] unit-test
 
-[ t ] [ now timestamp>micros system-micros - 1000000 < ] unit-test
 [ t ] [ 0 micros>timestamp unix-1970 = ] unit-test
 [ t ] [ 123456789000000 [ micros>timestamp timestamp>micros ] keep = ] unit-test
 [ t ] [ 123456789123456000 [ micros>timestamp timestamp>micros ] keep = ] unit-test
diff --git a/basis/furnace/cache/cache.factor b/basis/furnace/cache/cache.factor
index 676e41d3bc..abb41867a3 100644
--- a/basis/furnace/cache/cache.factor
+++ b/basis/furnace/cache/cache.factor
@@ -22,7 +22,7 @@ server-state f
 
 : expire-state ( class -- )
     new
-        -1/0. system-micros [a,b] >>expires
+        -1/0. gmt timestamp>micros [a,b] >>expires
     delete-tuples ;
 
 TUPLE: server-state-manager < filter-responder timeout ;
diff --git a/basis/ui/gestures/gestures-docs.factor b/basis/ui/gestures/gestures-docs.factor
index bb33e28da3..592a3fea3a 100644
--- a/basis/ui/gestures/gestures-docs.factor
+++ b/basis/ui/gestures/gestures-docs.factor
@@ -174,7 +174,7 @@ HELP: hand-last-button
 { $var-description "Global variable. The mouse button most recently pressed." } ;
 
 HELP: hand-last-time
-{ $var-description "Global variable. The timestamp of the most recent mouse button click. This timestamp has the same format as the output value of " { $link system-micros } "." } ;
+{ $var-description "Global variable. The timestamp of the most recent mouse button click. This timestamp has the same format as the output value of " { $link nano-count } "." } ;
 
 HELP: hand-buttons
 { $var-description "Global variable. A vector of mouse buttons currently held down." } ;
diff --git a/basis/uuid/uuid.factor b/basis/uuid/uuid.factor
index 118db67d90..6c1e1de55b 100644
--- a/basis/uuid/uuid.factor
+++ b/basis/uuid/uuid.factor
@@ -1,10 +1,9 @@
 ! Copyright (C) 2008 John Benediktsson
 ! See http://factorcode.org/license.txt for BSD license
-USING: byte-arrays checksums checksums.md5 checksums.sha
-kernel math math.parser math.ranges random unicode.case 
-sequences strings system io.binary ;
-
-IN: uuid 
+USING: byte-arrays calendar checksums checksums.md5
+checksums.sha io.binary kernel math math.parser math.ranges
+random sequences strings system unicode.case ;
+IN: uuid
 
 <PRIVATE
 
@@ -12,7 +11,7 @@ IN: uuid
     ! 0x01b21dd213814000L is the number of 100-ns intervals
     ! between the UUID epoch 1582-10-15 00:00:00 and the 
     ! Unix epoch 1970-01-01 00:00:00.
-    system-micros 10 * HEX: 01b21dd213814000 +
+    gmt timestamp>micros 10 * HEX: 01b21dd213814000 +
     [ -48 shift HEX: 0fff bitand ] 
     [ -32 shift HEX: ffff bitand ]
     [ HEX: ffffffff bitand ]
diff --git a/extra/space-invaders/space-invaders.factor b/extra/space-invaders/space-invaders.factor
index 14277a1f28..a287c419d3 100755
--- a/extra/space-invaders/space-invaders.factor
+++ b/extra/space-invaders/space-invaders.factor
@@ -359,8 +359,8 @@ M: space-invaders update-video ( value addr cpu -- )
 
 : sync-frame ( micros -- micros )
   #! Sleep until the time for the next frame arrives.
-  1000 60 / >fixnum + system:system-micros - dup 0 >
-  [ milliseconds threads:sleep ] [ drop threads:yield ] if system:system-micros ;
+  1000 60 / >fixnum + gmt timestamp>micros - dup 0 >
+  [ milliseconds threads:sleep ] [ drop threads:yield ] if gmt timestamp>micros ;
 
 : invaders-process ( micros gadget -- )
   #! Run a space invaders gadget inside a 
@@ -378,7 +378,7 @@ M: space-invaders update-video ( value addr cpu -- )
 M: invaders-gadget graft* ( gadget -- )
   dup cpu>> init-sounds
   f over quit?<<
-  [ system:system-micros swap invaders-process ] curry
+  [ gmt timestamp>micros swap invaders-process ] curry
   "Space invaders" threads:spawn drop ;
 
 M: invaders-gadget ungraft* ( gadget -- )
diff --git a/extra/tetris/game/game.factor b/extra/tetris/game/game.factor
index a45e655131..d96434fbe1 100644
--- a/extra/tetris/game/game.factor
+++ b/extra/tetris/game/game.factor
@@ -35,7 +35,7 @@ CONSTANT: default-height 20
     rows>> 1 + 10 / ceiling ;
 
 : update-interval ( tetris -- interval )
-    level>> 1 - 60 * 1000000 swap - ;
+    level>> 1 - 60 * 1,000,000,000 swap - ;
 
 : add-block ( tetris block -- )
     over [ board>> ] 2dip current-piece tetromino>> colour>> set-block ;
@@ -104,10 +104,10 @@ CONSTANT: default-height 20
     dup { 0 1 } tetris-move [ move-drop ] [ lock-piece ] if ;
 
 : update ( tetris -- )
-    system-micros over last-update>> -
+    nano-count over last-update>> -
     over update-interval > [
         dup move-down
-        system-micros >>last-update
+        nano-count >>last-update
     ] when drop ;
 
 : ?update ( tetris -- )