diff --git a/c/Makefile.a6nt b/c/Makefile.a6nt
index 4b8c301056..e14c7eae88 100644
--- a/c/Makefile.a6nt
+++ b/c/Makefile.a6nt
@@ -51,13 +51,13 @@ csrc=statics.c segment.c alloc.c symbol.c intern.c gcwrapper.c gc-oce.c gc-ocd.c
  number.c schsig.c io.c new-io.c print.c fasl.c vfasl.c stats.c\
  foreign.c prim.c prim5.c flushcache.c\
  windows.c\
- schlib.c thread.c expeditor.c scheme.c compress-io.c
+ schlib.c thread.c expeditor.c scheme.c compress-io.c random.c
 
 cobj=statics.obj segment.obj alloc.obj symbol.obj intern.obj gcwrapper.obj gc-oce.obj gc-ocd.obj\
  number.obj schsig.obj io.obj new-io.obj print.obj fasl.obj vfasl.obj stats.obj\
  foreign.obj prim.obj prim5.obj flushcache.obj\
  windows.obj\
- schlib.obj thread.obj expeditor.obj scheme.obj compress-io.obj
+ schlib.obj thread.obj expeditor.obj scheme.obj compress-io.obj random.obj
 
 hsrc=system.h types.h version.h globals.h externs.h compress-io.h segment.h gc.c thread.h sort.h itest.c
 
diff --git a/c/Makefile.i3nt b/c/Makefile.i3nt
index 7180bcfb2b..78a7e2786b 100644
--- a/c/Makefile.i3nt
+++ b/c/Makefile.i3nt
@@ -50,13 +50,13 @@ csrc=statics.c segment.c alloc.c symbol.c intern.c gcwrapper.c gc-oce.c gc-ocd.c
  number.c schsig.c io.c new-io.c print.c fasl.c vfasl.c stats.c\
  foreign.c prim.c prim5.c flushcache.c\
  windows.c\
- schlib.c thread.c expeditor.c scheme.c compress-io.c
+ schlib.c thread.c expeditor.c scheme.c compress-io.c random.c
 
 cobj=statics.obj segment.obj alloc.obj symbol.obj intern.obj gcwrapper.obj gc-oce.obj gc-ocd.obj\
  number.obj schsig.obj io.obj new-io.obj print.obj fasl.obj vfasl.obj stats.obj\
  foreign.obj prim.obj prim5.obj flushcache.obj\
  windows.obj\
- schlib.obj thread.obj expeditor.obj scheme.obj compress-io.obj
+ schlib.obj thread.obj expeditor.obj scheme.obj compress-io.obj random.obj
 
 hsrc=system.h types.h version.h globals.h externs.h compress-io.h segment.h gc.c thread.h sort.h itest.c
 
diff --git a/c/Makefile.ta6nt b/c/Makefile.ta6nt
index bead44f61a..09083c91b6 100644
--- a/c/Makefile.ta6nt
+++ b/c/Makefile.ta6nt
@@ -51,13 +51,13 @@ csrc=statics.c segment.c alloc.c symbol.c intern.c gcwrapper.c gc-oce.c gc-ocd.c
  number.c schsig.c io.c new-io.c print.c fasl.c vfasl.c stats.c\
  foreign.c prim.c prim5.c flushcache.c\
  windows.c\
- schlib.c thread.c expeditor.c scheme.c compress-io.c
+ schlib.c thread.c expeditor.c scheme.c compress-io.c random.c
 
 cobj=statics.obj segment.obj alloc.obj symbol.obj intern.obj gcwrapper.obj gc-oce.obj gc-ocd.obj\
  number.obj schsig.obj io.obj new-io.obj print.obj fasl.obj vfasl.obj stats.obj\
  foreign.obj prim.obj prim5.obj flushcache.obj\
  windows.obj\
- schlib.obj thread.obj expeditor.obj scheme.obj compress-io.obj
+ schlib.obj thread.obj expeditor.obj scheme.obj compress-io.obj random.obj
 
 hsrc=system.h types.h version.h globals.h externs.h compress-io.h segment.h gc.c thread.h sort.h itest.c
 
diff --git a/c/Makefile.ti3nt b/c/Makefile.ti3nt
index df82918024..3002f3ee66 100644
--- a/c/Makefile.ti3nt
+++ b/c/Makefile.ti3nt
@@ -50,13 +50,13 @@ csrc=statics.c segment.c alloc.c symbol.c intern.c gcwrapper.c gc-oce.c gc-ocd.c
  number.c schsig.c io.c new-io.c print.c fasl.c vfasl.c stats.c\
  foreign.c prim.c prim5.c flushcache.c\
  windows.c\
- schlib.c thread.c expeditor.c scheme.c compress-io.c
+ schlib.c thread.c expeditor.c scheme.c compress-io.c random.c
 
 cobj=statics.obj segment.obj alloc.obj symbol.obj intern.obj gcwrapper.obj gc-oce.obj gc-ocd.obj\
  number.obj schsig.obj io.obj new-io.obj print.obj fasl.obj vfasl.obj stats.obj\
  foreign.obj prim.obj prim5.obj flushcache.obj\
  windows.obj\
- schlib.obj thread.obj expeditor.obj scheme.obj compress-io.obj
+ schlib.obj thread.obj expeditor.obj scheme.obj compress-io.obj random.obj
 
 hsrc=system.h types.h version.h globals.h externs.h compress-io.h segment.h gc.c thread.h sort.h itest.c
 
diff --git a/c/Mf-base b/c/Mf-base
index afe5fde202..74c8b4896b 100644
--- a/c/Mf-base
+++ b/c/Mf-base
@@ -34,7 +34,7 @@ KernelLibLinkLibs=${zlibLib} ${LZ4Lib}
 
 kernelsrc=statics.c segment.c alloc.c symbol.c intern.c gcwrapper.c gc-ocd.c gc-oce.c\
  number.c schsig.c io.c new-io.c print.c fasl.c vfasl.c stats.c foreign.c prim.c prim5.c flushcache.c\
- schlib.c thread.c expeditor.c scheme.c compress-io.c
+ schlib.c thread.c expeditor.c scheme.c compress-io.c random.c
 
 kernelobj=${kernelsrc:%.c=%.$o} ${mdobj}
 
diff --git a/c/externs.h b/c/externs.h
index 4e50cc7aff..6ffbaf5c13 100644
--- a/c/externs.h
+++ b/c/externs.h
@@ -420,5 +420,12 @@ extern char *S_windows_getcwd(char *buffer, int maxlen);
 extern void S_expeditor_init PROTO((void));
 #endif /* FEATURE_EXPEDITOR */
 
+/* random.c */
+uptr S_random_state_next_integer PROTO((ptr s, uptr n));
+double S_random_state_next_double PROTO((ptr s));
+void S_random_state_init PROTO((ptr s, UINT x));
+IBOOL S_random_state_check PROTO((double x10, double x11, double x12,
+                                  double x20, double x21, double x22));
+
 /* statics.c */
 extern void scheme_statics();
diff --git a/c/prim5.c b/c/prim5.c
index 414a12dfed..98d1fd84a8 100644
--- a/c/prim5.c
+++ b/c/prim5.c
@@ -1596,6 +1596,10 @@ void S_prim5_init() {
     Sforeign_symbol("(cs)s_float", (void *)s_float);
     Sforeign_symbol("(cs)s_flrandom", (void *)s_flrandom);
     Sforeign_symbol("(cs)s_fxrandom", (void *)s_fxrandom);
+    Sforeign_symbol("(cs)s_random_state_next_integer", (void *)S_random_state_next_integer);
+    Sforeign_symbol("(cs)s_random_state_next_double", (void *)S_random_state_next_double);
+    Sforeign_symbol("(cs)s_random_state_init", (void *)S_random_state_init);
+    Sforeign_symbol("(cs)s_random_state_check", (void *)S_random_state_check);
     Sforeign_symbol("(cs)s_integer_length", (void *)S_integer_length);
     Sforeign_symbol("(cs)s_big_first_bit_set", (void *)S_big_first_bit_set);
     Sforeign_symbol("(cs)s_make_code", (void *)s_make_code);
diff --git a/c/random.c b/c/random.c
new file mode 100644
index 0000000000..d496d3a369
--- /dev/null
+++ b/c/random.c
@@ -0,0 +1,188 @@
+#include "system.h"
+
+/*
+  Based on
+
+   Implementation of SRFI-27 core generator in C for Racket.
+   dvanhorn@cs.uvm.edu
+
+  and
+
+   54-BIT (double) IMPLEMENTATION IN C OF THE "MRG32K3A" GENERATOR
+   ===============================================================
+
+   Sebastian.Egner@philips.com, Mar-2002, in ANSI-C and Scheme 48 0.57
+
+   This code is a C-implementation of Pierre L'Ecuyer's MRG32k3a generator.
+   The code uses (double)-arithmetics, assuming that it covers the range
+   {-2^53..2^53-1} exactly (!). The code of the generator is based on the
+   L'Ecuyer's own implementation of the generator. Please refer to the
+   file 'mrg32k3a.scm' for more information about the method.
+*/
+
+/* Representation is arecord with 6 `double` fields: */
+
+#define RANDSTATEX10(x) (((double*)&RECORDINSTIT(x, 0))[0])
+#define RANDSTATEX11(x) (((double*)&RECORDINSTIT(x, 0))[1])
+#define RANDSTATEX12(x) (((double*)&RECORDINSTIT(x, 0))[2])
+#define RANDSTATEX20(x) (((double*)&RECORDINSTIT(x, 0))[3])
+#define RANDSTATEX21(x) (((double*)&RECORDINSTIT(x, 0))[4])
+#define RANDSTATEX22(x) (((double*)&RECORDINSTIT(x, 0))[5])
+
+/* The Generator
+   =============
+*/
+
+/* moduli of the components */
+#define Im1 0xffffff2f
+#define Im2 0xffffa6bb
+#define m1 4294967087.0
+#define m2 4294944443.0
+
+/* recursion coefficients of the components */
+#define a12  1403580.0
+#define a13n  810728.0
+#define a21   527612.0
+#define a23n 1370589.0
+
+/* normalization factor 1/(m1 + 1) */
+#define norm 2.328306549295728e-10
+
+/* the actual generator */
+
+static double mrg32k3a(ptr s) { /* (double), in {0..m1-1} */
+  double x10, x20, y;
+  iptr   k10, k20;
+
+  /* component 1 */
+  x10  = a12*(RANDSTATEX11(s)) - a13n*(RANDSTATEX12(s));
+  k10  = (iptr)(x10 / m1);
+  x10 -= k10 * m1;
+  if (x10 < 0.0)
+    x10 += m1;
+  RANDSTATEX12(s) = RANDSTATEX11(s);
+  RANDSTATEX11(s) = RANDSTATEX10(s);
+  RANDSTATEX10(s) = x10;
+
+  /* component 2 */
+  x20  = a21*(RANDSTATEX20(s)) - a23n*(RANDSTATEX22(s));
+  k20  = (iptr)(x20 / m2);
+  x20 -= k20 * m2;
+  if (x20 < 0.0)
+    x20 += m2;
+  RANDSTATEX22(s) = RANDSTATEX21(s);
+  RANDSTATEX21(s) = RANDSTATEX20(s);
+  RANDSTATEX20(s) = x20;
+
+  /* combination of component */
+  y = x10 - x20;
+  if (y < 0.0)
+    y += m1;
+  return y;
+}
+
+/**************************************************/
+
+/* The number `n` must be no more than 4294967087 */
+uptr S_random_state_next_integer(ptr s, uptr n)
+{
+  double  x, q, qn, xq;
+
+  /* generate result in {0..n-1} using the rejection method */
+  q  = (double)( (uptr)(m1 / (double)n) );
+  qn = q * n;
+  do {
+    x = mrg32k3a(s);
+  } while (x >= qn);
+  xq = x / q;
+
+  /* return result */
+  return (uptr)xq;
+}
+
+double S_random_state_next_double(ptr s)
+{
+  double  x;
+  x = mrg32k3a(s);
+  return (x + 1.0) * norm;
+}
+
+/**************************************************/
+
+static UINT _random_m(UINT *_x)
+{
+  UINT x, y;
+  x = *_x;
+  y = x & 0xFFFF;
+  x = (30903 * y) + (x >> 16);
+  *_x = x;
+  return y;
+}
+
+static int _random_n(UINT *_x, int n)
+{
+  return ((_random_m(_x) << 16) + _random_m(_x)) % n;
+}
+
+static void sch_srand_half(UINT x, ptr s)
+{
+  /* Due to integer overflow, this doesn't match the Scheme implementation!
+     We use "int" instead of "long" to make the overflow consistent
+     across platforms (since "long" is sometimes 64 bits). */
+  UINT z;
+  z = _random_n(&x, Im1-1);
+  RANDSTATEX10(s) = (double)(1 + (((UINT)RANDSTATEX10(s) + z) % (Im1 - 1)));
+  z = _random_n(&x, Im1);
+  RANDSTATEX11(s) = (double)(((UINT)RANDSTATEX11(s) + z) % Im1);
+  z = _random_n(&x, Im1);
+  RANDSTATEX12(s) = (double)(((UINT)RANDSTATEX12(s) + z) % Im1);
+  z = _random_n(&x, Im2-1);
+  RANDSTATEX20(s) = (double)(1 + (((UINT)RANDSTATEX20(s) + z) % (Im2 - 1)));
+  z = _random_n(&x, Im2);
+  RANDSTATEX21(s) = (double)(((UINT)RANDSTATEX21(s) + z) % Im2);
+  z = _random_n(&x, Im2);
+  RANDSTATEX22(s) = (double)(((UINT)RANDSTATEX22(s) + z) % Im2);
+
+  /* Due to the mismatch, maybe it's possible that we can hit a degeneracy?
+     Double-check, just in case... */
+  if (!RANDSTATEX10(s) && !RANDSTATEX11(s) && !RANDSTATEX12(s))
+    RANDSTATEX10(s) = 1;
+  if (!RANDSTATEX20(s) && !RANDSTATEX21(s) && !RANDSTATEX22(s))
+    RANDSTATEX20(s) = 1;
+}
+
+void S_random_state_init(ptr s, UINT x)
+{
+  /* Initial values are from Sebastian Egner's implementation: */
+  RANDSTATEX10(s) = 1062452522.0;
+  RANDSTATEX11(s) = 2961816100.0;
+  RANDSTATEX12(s) = 342112271.0;
+  RANDSTATEX20(s) = 2854655037.0;
+  RANDSTATEX21(s) = 3321940838.0;
+  RANDSTATEX22(s) = 3542344109.0;
+
+  sch_srand_half(x & 0xFFFF, s);
+  sch_srand_half((x >> 16) & 0xFFFF, s);
+}
+
+/**************************************************/
+
+IBOOL S_random_state_check(double x10, double x11, double x12,
+                           double x20, double x21, double x22)
+{
+#define CHECK_RS_FIELD(x, top) if ((x < 0.0) || (x > ((top) - 1))) return 0;
+
+  CHECK_RS_FIELD(x10, Im1)
+  CHECK_RS_FIELD(x11, Im1)
+  CHECK_RS_FIELD(x12, Im1)
+  CHECK_RS_FIELD(x20, Im2)
+  CHECK_RS_FIELD(x21, Im2)
+  CHECK_RS_FIELD(x22, Im2)
+
+  if ((x10 == 0.0) && (x11 == 0.0) && (x12 == 0.0))
+    return 0;
+  if ((x20 == 0.0) && (x21 == 0.0) && (x22 == 0.0))
+    return 0;
+
+  return 1;
+}
diff --git a/csug/numeric.stex b/csug/numeric.stex
index 29c673315d..a49531824d 100644
--- a/csug/numeric.stex
+++ b/csug/numeric.stex
@@ -1419,6 +1419,86 @@ random seed to the argument.
     (eqv? (random 1.0) r1))) ;=> #t
 \endschemedisplay
 
+%----------------------------------------------------------------------------
+\entryheader
+\formdef{make-pseudo-random-generator}{\categoryprocedure}{(make-pseudo-random-generator)}
+\returns a fresh pseudo-random generator
+\listlibraries
+\endnoskipentryheader
+
+\noindent
+Creates a pseduo-random generator state for use with
+\scheme{pseduo-random-generator-next!}. This generator use a more
+modern algorithm than \scheme{random} and generates number sequences
+that better approximate true randomness.
+
+The initial state of the pseduo-random generator is based on the
+current time, which is good enough for generating variability in most
+programs but not good enough for security purposes.
+
+%----------------------------------------------------------------------------
+\entryheader
+\formdef{pseudo-random-generator?}{\categoryprocedure}{(pseudo-random-generator? \var{val})}
+\returns a boolean
+\listlibraries
+\endnoskipentryheader
+
+\noindent
+Checks whether \var{val} is a pseudo-random generator state.
+
+%----------------------------------------------------------------------------
+\entryheader
+\formdef{pseudo-random-generator-next!}{\categoryprocedure}{(pseudo-random-generator-next! \var{prgen})}
+\formdef{pseudo-random-generator-next!}{\categoryprocedure}{(pseudo-random-generator-next! \var{prgen} \var{below-int})}
+\returns a pseduo-random number
+\listlibraries
+\endnoskipentryheader
+
+\noindent
+\var{prgen} must be a psuedo-random generator state. If \var{below-int} is
+provided, it must be a positive, exact integer.
+
+Steps a pseduo-random generator to produce a number. The result is an
+inexact number between \scheme{0.0} (inclusive) and \scheme{1.0}
+(exclusive) if \var{below-int} is not provided. If \scheme{below-int} is
+provided, the result is an exact integer between \scheme{0} (inclusive)
+and \scheme{below-int} (exclusive).
+
+%----------------------------------------------------------------------------
+\entryheader
+\formdef{pseudo-random-generator-seed!}{\categoryprocedure}{(pseudo-random-generator-seed! \var{prgen} \var{seed-int})}
+\returns unspecified
+\listlibraries
+\endnoskipentryheader
+
+\noindent
+\var{prgen} must be a psuedo-random generator state, and \var{seed-int} must
+be a positive, exact integer.
+
+Sets the state of a pseduo-random generator using only 31 or so bits
+of \var{seed-int}. This procedure is useful for initializing the state
+of a pseduo-random generator to one of a small number of known states
+for triggering predicatble output, but it is not a good way to put a
+generator into an unpredictable state.
+
+%----------------------------------------------------------------------------
+\entryheader
+\formdef{pseudo-random-generator->vector}{\categoryprocedure}{(pseudo-random-generator->vector \var{prgen})}
+\formdef{vector->pseudo-random-generator}{\categoryprocedure}{(vector->pseudo-random-generator \var{vec})}
+\formdef{vector->pseudo-random-generator!}{\categoryprocedure}{(vector->pseudo-random-generator! \var{prgen} \var{vec})}
+\returns unspecified
+\listlibraries
+\endnoskipentryheader
+
+\noindent
+\var{prgen} must be a psuedo-random generator state, and \var{vec} must
+be a vector previously produced by \scheme{pseudo-random-generator->vector}.
+
+\scheme{pseudo-random-generator->vector} converts the current state of
+a pseduo-random generator to a vector of numbers, \scheme{vector->pseudo-random-generator}
+creates a fresh pseudo-random generator with the same state, and
+\scheme{vector->pseudo-random-generator!}
+changes an existing pseudo-random generator to have the same state.
 
 
 \section{Miscellaneous Numeric Operations\label{SECTNUMERICMISC}}
diff --git a/makefiles/Mf-install.in b/makefiles/Mf-install.in
index 9e66ef8711..fe5ea645c7 100644
--- a/makefiles/Mf-install.in
+++ b/makefiles/Mf-install.in
@@ -62,7 +62,7 @@ InstallLZ4Target=
 #                 no changes should be needed below this point                #
 ###############################################################################
 
-Version=csv9.5.3.2
+Version=csv9.5.3.3
 Include=boot/$m
 PetiteBoot=boot/$m/petite.boot
 SchemeBoot=boot/$m/scheme.boot
diff --git a/mats/5_3.ms b/mats/5_3.ms
index 50c913aab2..f01c883559 100644
--- a/mats/5_3.ms
+++ b/mats/5_3.ms
@@ -2567,6 +2567,80 @@
       #t)
  )
 
+(mat pseudo-random-generator
+    (pseudo-random-generator? (make-pseudo-random-generator))
+    (not (pseudo-random-generator? 10))
+    (not (pseudo-random-generator? (vector 1 2 3)))
+
+    (error? (pseudo-random-generator-next! 10))
+    (error? (pseudo-random-generator-next! (vector 1 2 3)))
+
+    (error? (pseudo-random-generator-next! (make-pseudo-random-generator) "apple"))
+    (error? (pseudo-random-generator-next! (make-pseudo-random-generator) 0))
+    (error? (pseudo-random-generator-next! (make-pseudo-random-generator) -10))
+    (error? (pseudo-random-generator-next! (make-pseudo-random-generator) (- (expt 2 100))))
+    (error? (pseudo-random-generator-next! (make-pseudo-random-generator) 10.0))
+
+    (error? (pseudo-random-generator-seed! 10 10))
+    (error? (pseudo-random-generator-seed! (vector 1 2 3) 10))
+    (error? (pseudo-random-generator-seed! (make-pseudo-random-generator) 10.0))
+    (error? (pseudo-random-generator-seed! (make-pseudo-random-generator) 0))
+    (error? (pseudo-random-generator-seed! (make-pseudo-random-generator) -1))
+
+    (error? (pseudo-random-generator->vector 0))
+    (error? (vector->pseudo-random-generator 0))
+    (error? (vector->pseudo-random-generator (vector 1 2 3 4 5)))
+    (error? (vector->pseudo-random-generator (vector 1.0 2 3 4 5 6)))
+    (error? (vector->pseudo-random-generator (vector 1 #f 3 4 5 6)))
+    (error? (vector->pseudo-random-generator (vector 0 0 0 0 0 0))) ; would be degenerate state
+    (error? (vector->pseudo-random-generator! 0 (vector 1 2 3 4 5)))
+    (error? (vector->pseudo-random-generator! (make-pseudo-random-generator) 0))
+    (error? (vector->pseudo-random-generator! (make-pseudo-random-generator) (vector 0 0 0 0 0 0)))
+
+    (begin
+      (define prgen (make-pseudo-random-generator))
+      (define init-pregen-vec (pseudo-random-generator->vector prgen))
+      (vector? init-pregen-vec))
+    (equal? init-pregen-vec (pseudo-random-generator->vector prgen))
+    (begin
+      (define first-prgen-number (pseudo-random-generator-next! prgen))
+      (inexact? first-prgen-number))
+    (and (<= 0.0 first-prgen-number)
+         (< first-prgen-number 1.0))
+    (not (equal? init-pregen-vec (pseudo-random-generator->vector prgen)))
+    (= first-prgen-number
+       (pseudo-random-generator-next!
+        (vector->pseudo-random-generator init-pregen-vec)))
+    (let loop ([i 10000])
+      (or (zero? i)
+          (let ([n (pseudo-random-generator-next! prgen i)])
+            (and (exact? n)
+                 (integer? n)
+                 (< -1 n i)
+                 (loop (sub1 i))))))
+    (equal? (void) (vector->pseudo-random-generator! prgen init-pregen-vec))
+    (= first-prgen-number (pseudo-random-generator-next! prgen))
+    (equal? (void) (pseudo-random-generator-seed! prgen 45))
+    (= 0.970453319804345 (pseudo-random-generator-next! prgen))
+    (= 0.41754101818626094 (pseudo-random-generator-next! prgen))
+    (= 0.13061439482676662 (pseudo-random-generator-next! prgen))
+    (let ([hits (make-vector 10)])
+      (let loop ([i 1000])
+        (unless (zero? i)
+          (let* ([n (pseudo-random-generator-next! prgen (expt 10 1000))]
+                 [k (quotient n (expt 10 999))])
+            (vector-set! hits k (add1 (vector-ref hits k)))
+            (loop (sub1 i)))))
+      ;; We expect about 100 hits in each bin. Having less than 50 or
+      ;; more than 150 should be so etxremely unlikely that we can rely on
+      ;; it not happning:
+      (let loop ([i (vector-length hits)])
+        (or (= i 0)
+            (and (< 50 (vector-ref hits (sub1 i)) 150)
+                 (loop (sub1 i))))))
+ )
+      
+
 (mat inexact
     (error? (inexact))
     (error? (inexact 1 2))
diff --git a/mats/primvars.ms b/mats/primvars.ms
index 68486ef23d..153768066f 100644
--- a/mats/primvars.ms
+++ b/mats/primvars.ms
@@ -424,6 +424,7 @@
               [(pathname) "a" 'a #f]
               [(pfixnum) 1 0 #f]
               [(phantom-bytevector) *phantom-bytevector '#vu8(0) #f]
+              [(pseudo-random-generator) *pseudo-random-generator #f]
               [(port) (current-input-port) 0 #f]
               [(procedure) values 0 #f]
               [(ptr) 1.0+2.0i]
diff --git a/mats/root-experr-compile-0-f-f-f b/mats/root-experr-compile-0-f-f-f
index d4d5c654be..867d500c89 100644
--- a/mats/root-experr-compile-0-f-f-f
+++ b/mats/root-experr-compile-0-f-f-f
@@ -1308,6 +1308,27 @@ primvars.mo:Expected error in mat trace-output-port: "trace-output-port: #<input
 5_3.mo:Expected error in mat random-seed: "random-seed: invalid argument 0".
 5_3.mo:Expected error in mat random-seed: "random-seed: invalid argument -1".
 5_3.mo:Expected error in mat random-seed: "random-seed: invalid argument <int>".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-next!: not a pseudo-random generator 10".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-next!: not a pseudo-random generator #(1 2 3)".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-next!: not a positive exact integer "apple"".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-next!: not a positive exact integer 0".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-next!: not a positive exact integer -10".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-next!: not a positive exact integer -1267650600228229401496703205376".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-next!: not a positive exact integer 10.0".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-seed!: not a pseudo-random generator 10".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-seed!: not a pseudo-random generator #(1 2 3)".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-seed!: not a positive exact integer 10.0".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-seed!: not a positive exact integer 0".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator-seed!: not a positive exact integer -1".
+5_3.mo:Expected error in mat pseudo-random-generator: "pseudo-random-generator->vector: not a pseudo-random generator 0".
+5_3.mo:Expected error in mat pseudo-random-generator: "vector->pseudo-random-generator: not a valid pseudo-random generator state vector 0".
+5_3.mo:Expected error in mat pseudo-random-generator: "vector->pseudo-random-generator: not a valid pseudo-random generator state vector #(1 2 3 4 5)".
+5_3.mo:Expected error in mat pseudo-random-generator: "vector->pseudo-random-generator: not a valid pseudo-random generator state vector #(1.0 2 3 4 5 6)".
+5_3.mo:Expected error in mat pseudo-random-generator: "exact?: #f is not a number".
+5_3.mo:Expected error in mat pseudo-random-generator: "vector->pseudo-random-generator: not a valid pseudo-random generator state vector #(0 0 0 0 0 0)".
+5_3.mo:Expected error in mat pseudo-random-generator: "vector->pseudo-random-generator!: not a pseudo-random generator 0".
+5_3.mo:Expected error in mat pseudo-random-generator: "vector->pseudo-random-generator!: not a valid pseudo-random generator state vector 0".
+5_3.mo:Expected error in mat pseudo-random-generator: "vector->pseudo-random-generator!: not a valid pseudo-random generator state vector #(0 0 0 0 0 0)".
 5_3.mo:Expected error in mat inexact: "incorrect argument count in call (inexact)".
 5_3.mo:Expected error in mat inexact: "incorrect argument count in call (inexact 1 2)".
 5_3.mo:Expected error in mat inexact: "inexact: a is not a number".
diff --git a/s/5_3.ss b/s/5_3.ss
index da5a07fbf5..df8109b3aa 100644
--- a/s/5_3.ss
+++ b/s/5_3.ss
@@ -2597,6 +2597,115 @@
              [else (nonexact-integer-error '$quotient-remainder x)])]
          [else (nonexact-integer-error '$quotient-remainder y)])))
 
+(let ()
+  (define-record pseudo-random-generator
+    ((mutable double x10)
+     (mutable double x11)
+     (mutable double x12)
+     (mutable double x20)
+     (mutable double x21)
+     (mutable double x22))
+    ()
+    ((constructor create-pseudo-random-generator)
+     (predicate is-pseudo-random-generator?)))
+
+  (set! pseudo-random-generator?
+        (lambda (x) (is-pseudo-random-generator? x)))
+
+  (let ([init! (foreign-procedure "(cs)s_random_state_init" (scheme-object unsigned) void)])
+    (set! make-pseudo-random-generator
+          (lambda ()
+            (let ([s (create-pseudo-random-generator 0.0 0.0 0.0 0.0 0.0 0.0)]
+                  [t (current-time 'time-utc)])
+              (init! s (bitwise-and (+ (time-second t) (time-nanosecond t))
+                                    #xFFFFFFFF))
+              s)))
+    (set-who! pseudo-random-generator-seed!
+      (lambda (s n)
+        (unless (is-pseudo-random-generator? s) ($oops who "not a pseudo-random generator ~s" s))
+        (unless (or (and (fixnum? n) (fxpositive? n))
+                    (and (bignum? n)  ($bigpositive? n)))
+          ($oops who "not a positive exact integer ~s" n))
+        (init! s (bitwise-and n #xFFFFFFFF)))))
+
+  (set-who! pseudo-random-generator-next!
+     (let ([random-double (foreign-procedure "(cs)s_random_state_next_double"
+                            (scheme-object) double)]
+           [random-int (foreign-procedure "(cs)s_random_state_next_integer"
+                            (scheme-object uptr) uptr)])
+       (case-lambda
+        [(s)
+         (unless (is-pseudo-random-generator? s) ($oops who "not a pseudo-random generator ~s" s))
+         (random-double s)]
+        [(s x)
+         (define (random-integer s x)
+           (modulo (let loop ([bits (integer-length x)])
+                     (cond
+                      [(<= bits 0) 0]
+                      [else (bitwise-ior (bitwise-arithmetic-shift-left (loop (- bits 24)) 24)
+                                         (random-int s #xFFFFFF))]))
+                   x))
+         (unless (is-pseudo-random-generator? s) ($oops who "not a pseudo-random generator ~s" s))
+         (cond
+          [(fixnum? x)
+           (unless (fxpositive? x) ($oops who "not a positive exact integer ~s" x))
+           (meta-cond
+            [(fixnum? 4294967087)
+             (if (fx< x 4294967087)
+                 (random-int s x)
+                 (random-integer s x))]
+            [else
+             (random-int s x)])]
+          [(bignum? x)
+           (unless ($bigpositive? x) ($oops who "not a positive exact integer ~s" x))
+           (random-integer s x)]
+          [else
+           ($oops who "not a positive exact integer ~s" x)])])))
+
+  (set-who! pseudo-random-generator->vector
+    (lambda (s)
+      (unless (is-pseudo-random-generator? s) ($oops who "not a pseudo-random generator ~s" s))
+      (vector (inexact->exact (pseudo-random-generator-x10 s))
+              (inexact->exact (pseudo-random-generator-x11 s))
+              (inexact->exact (pseudo-random-generator-x12 s))
+              (inexact->exact (pseudo-random-generator-x20 s))
+              (inexact->exact (pseudo-random-generator-x21 s))
+              (inexact->exact (pseudo-random-generator-x22 s)))))
+
+  (let ([vector->prgen
+         (let ([ok? (foreign-procedure "(cs)s_random_state_check" (double double double double double double) boolean)])
+           (lambda (who s v)
+             (define (bad-vector)
+               ($oops who "not a valid pseudo-random generator state vector ~s" v))
+             (define (int->double i)
+               (unless (and (exact? i) (integer? i)) (bad-vector))
+               (exact->inexact i))
+             (unless (and (vector? v) (= 6 (vector-length v))) (bad-vector))
+             (let ([x10 (int->double (vector-ref v 0))]
+                   [x11 (int->double (vector-ref v 1))]
+                   [x12 (int->double (vector-ref v 2))]
+                   [x20 (int->double (vector-ref v 3))]
+                   [x21 (int->double (vector-ref v 4))]
+                   [x22 (int->double (vector-ref v 5))])
+               (unless (ok? x10 x11 x12 x20 x21 x22) (bad-vector))
+               (cond
+                [s
+                 (set-pseudo-random-generator-x10! s x10)
+                 (set-pseudo-random-generator-x11! s x11)
+                 (set-pseudo-random-generator-x12! s x12)
+                 (set-pseudo-random-generator-x20! s x20)
+                 (set-pseudo-random-generator-x21! s x21)
+                 (set-pseudo-random-generator-x22! s x22)]
+                [else
+                 (create-pseudo-random-generator x10 x11 x12 x20 x21 x22)]))))])
+
+    (set-who! vector->pseudo-random-generator
+      (lambda (vec) (vector->prgen who #f vec)))
+    (set-who! vector->pseudo-random-generator!
+      (lambda (s vec)
+        (unless (is-pseudo-random-generator? s) ($oops who "not a pseudo-random generator ~s" s))
+        (vector->prgen who s vec)))))
+
 (set! random
    (let ([fxrandom (foreign-procedure "(cs)s_fxrandom"
                       (scheme-object) scheme-object)]
diff --git a/s/cmacros.ss b/s/cmacros.ss
index 7e1743ff53..de21a1e3fd 100644
--- a/s/cmacros.ss
+++ b/s/cmacros.ss
@@ -328,7 +328,7 @@
                  [(_ foo e1 e2) e1] ...
                  [(_ bar e1 e2) e2]))))])))
 
-(define-constant scheme-version #x09050302)
+(define-constant scheme-version #x09050303)
 
 (define-syntax define-machine-types
   (lambda (x)
diff --git a/s/primdata.ss b/s/primdata.ss
index 3b4380f2da..a8af5e93cd 100644
--- a/s/primdata.ss
+++ b/s/primdata.ss
@@ -1468,6 +1468,7 @@
   (make-output-port [sig [(procedure string) -> (textual-output-port)]] [flags alloc])
   (make-parameter [sig [(ptr) (ptr procedure) -> (procedure)]] [flags true cp02 cp03])
   (make-phantom-bytevector [sig [(uptr) -> (phantom-bytevector)]] [flags true])
+  (make-pseudo-random-generator [sig [() -> (pseudo-random-generator)]] [flags true])
   (make-record-type [sig [(sub-ptr sub-list) (maybe-rtd sub-ptr sub-list) -> (rtd)]] [flags pure alloc cp02])
   (make-source-condition [sig [(ptr) -> (condition)]] [flags pure unrestricted mifoldable discard])
   (make-source-file-descriptor [sig [(string binary-input-port) (string binary-input-port ptr) (string binary-input-port ptr ptr) -> (sfd)]] [flags true])
@@ -1565,6 +1566,10 @@
   (putprop [sig [(symbol ptr ptr) -> (void)]] [flags true safeongoodargs])
   (putenv [sig [(string string) -> (void)]] [flags true])
   (profile-query-weight [sig [(ptr) -> (maybe-flonum)]] [flags unrestricted discard])
+  (pseudo-random-generator->vector [sig [(pseudo-random-generator) -> (vector)]] [flags])
+  (pseudo-random-generator-seed! [sig [(pseudo-random-generator sub-number) -> (void)]] [flags])
+  (pseudo-random-generator-next! [sig [(pseudo-random-generator) -> (number)] [(sub-number pseudo-random-generator) -> (number)]] [flags])
+  (pseudo-random-generator? [sig [(ptr) -> (boolean)]] [flags pure unrestricted mifoldable discard])
   (random [sig [(sub-number) -> (number)]] [flags alloc])
   (ratnum? [sig [(ptr) -> (boolean)]] [flags pure unrestricted mifoldable discard])
   (read-token [sig [() (textual-input-port) (textual-input-port sfd) -> (symbol ptr maybe-uint maybe-uint)]] [flags])
@@ -1733,6 +1738,8 @@
   (vector-cas! [sig [(vector sub-index ptr ptr) -> (boolean)]] [flags])
   (vector-copy [sig [(vector) -> (vector)]] [flags alloc safeongoodargs])
   (vector->immutable-vector [sig [(vector) -> (vector)]] [flags alloc safeongoodargs])
+  (vector->pseudo-random-generator [sig [(vector) -> (pseudo-random-generator)]] [flags])
+  (vector->pseudo-random-generator! [sig [(pseudo-random-generator vector) -> (void)]] [flags])
   (vector-set-fixnum! [sig [(vector sub-index fixnum) -> (void)]] [flags true])
   (virtual-register [sig [(sub-index) -> (ptr)]] [flags discard])
   (virtual-register-count [sig [() -> (length)]] [flags pure unrestricted true cp02])