diff --git a/h/ocm_chan.h b/h/ocm_chan.h
new file mode 100644
index 000000000..ff66f8594
--- /dev/null
+++ b/h/ocm_chan.h
@@ -0,0 +1,47 @@
+/*	ocm_chan.h - channel definitions */
+#include <stdio.h>
+#include "ocm_parco.h"
+
+typedef union channel {
+	struct {		/* Interprocess channel */
+		char _type;	/* Channel type, see note */
+		char synch;	/* State in channel synchronization */
+		long val;	/* Transmitted value */
+	} c;
+	struct {		/* File channel */
+		char _type;	/* Dummy field, see note */
+		char index;	/* Index in the file array */
+		char flgs;	/* Status flags: in use & readahead */
+		char preread;	/* Possible preread character */
+	} f;
+} chan;
+#define type		c._type	/* Channel type */
+/* Note: The channel type should not be part of each structure in chan. But
+ * the C alignment rules would make chan about 50% bigger if we had done it
+ * the right way. Note that the order of fields in a struct cannot be a problem
+ * as long as struct c is the largest within the union.
+ */
+
+#define C_T_CHAN	0	/* Type of a interprocess channel */
+#define C_T_FILE	1	/* Type of a file channel */
+
+#define C_S_FREE	0	/* IP channel is free */
+#define C_S_ANY		1	/* IP channel contains data */
+#define C_S_ACK		2	/* IP channel data is removed */
+
+#define C_F_EOF		(-1L)	/* File channel returns EOF */
+#define C_F_TEXT	(-2L)	/* File channel becomes line oriented */
+#define C_F_RAW		(-3L)	/* File channel becomes character oriented */
+
+#define C_F_INUSE	0x01	/* File channel is connected to a UNIX file */
+#define C_F_READAHEAD	0x02	/* File channel has a preread character */
+
+extern chan file[20];	/* Array of file channels */
+extern FILE *unix_file[20];	/* Pointers to buffered UNIX files */
+
+void c_init();
+
+void chan_in(), cbyte_in(), c_wa_in(), c_ba_in();
+void chan_out(), c_wa_out(), c_ba_out();
+
+int chan_any();
diff --git a/h/ocm_parco.h b/h/ocm_parco.h
new file mode 100644
index 000000000..1588d43c3
--- /dev/null
+++ b/h/ocm_parco.h
@@ -0,0 +1,18 @@
+/*	parco.h - Define names for simulation routines
+ *
+ *      This file is to be included by users of the higher-level routines
+ *
+ */
+
+void pc_begin(), resumenext(), parend(), resume(), coend();
+int pc_fork();
+
+#define nullid	((int *) 0 - (int *) 0)
+	/* I.e. a 0 of type "pointer difference" */
+
+#define parbegin(sbrk)		pc_begin(sbrk, nullid)
+#define parfork()		pc_fork(nullid)
+#define cobegin(sbrk, id)	pc_begin(sbrk, id)
+#define cofork(id)		pc_fork(id)
+
+extern int deadlock;
diff --git a/h/ocm_proc.h b/h/ocm_proc.h
new file mode 100644
index 000000000..3f716e812
--- /dev/null
+++ b/h/ocm_proc.h
@@ -0,0 +1,56 @@
+/*	process.h - Define administration types and functions
+ *
+ *      This file is to be included by implementors of the higher
+ *      level routines
+ *
+ */
+#include "ocm_parco.h"
+
+#ifndef ptrdiff	/* This type must be able to hold a pointer difference */
+#if EM_WSIZE <EM_PSIZE
+#define ptrdiff long
+#else
+#define ptrdiff int	/* Define as long int if necessary */
+#endif
+#endif
+
+#define nil	0
+void *alloc(), free();
+
+typedef ptrdiff wordsize, identification;
+
+wordsize top_size();
+int top_save();
+void top_load();		/* Primitives */
+
+struct procgroup;
+
+struct process {
+	struct process *next;	/* Next process in the same group */
+	struct procgroup *down;	/* Process group running under this process */
+	void *stack;		/* Pointer to the saved stack top */
+	identification id;	/* Coroutine identification */
+};
+
+#define init_between	__i_b__	/* These names are hidden */
+#define save_between	__s_b__
+#define load_betweens	__l_b__
+#define delete_between	__d_b__
+
+void init_between(), save_between(), load_betweens(), delete_between();
+
+struct procgroup {
+	struct process **active;/* Active process within this group */
+	struct procgroup *up;	/* The group that this group belongs to */
+	struct process *first;	/* List of processes belonging to this group */
+	void *s_brk;		/* Point where the stack is split */
+	void *between;		/* Stack space between s_brk and up->s_brk */
+};
+
+#define group		__grp__	/* Ignore this please */
+#define highest_group	__hgrp__
+
+extern struct procgroup *group;		/* Current running group */
+extern struct procgroup *highest_group;	/* highest group that has been seen
+					 * while searching for a process
+					 */