diff --git a/kinclude/ktypes.h b/kinclude/ktypes.h
new file mode 100644
index 0000000..4bb4284
--- /dev/null
+++ b/kinclude/ktypes.h
@@ -0,0 +1,67 @@
+#ifndef H_ktypes
+#define H_ktypes
+
+/*
+ *  Error codes
+ */
+
+enum error_code {
+    ENOCODE = -1,   // invalid syscall code
+    EINVAL  = -2,   // invalid argument value
+    ENOMEM  = -3,   // not enough memory
+};
+
+/*
+ *  Scheduling types
+ */
+
+enum process_status {
+    PROC_DEAD       = 0,
+    PROC_RDY        = 1,
+    PROC_WAIT_PROC  = 2,
+    PROC_WAIT_SLEEP = 3,
+};
+
+// process structure:
+typedef struct ProcessControlBlock ProcessControlBlock;
+struct ProcessControlBlock {
+    int pid;
+    int pc;
+    int regs[31];
+    int exit_code;
+    // scheduling information
+    enum process_status status;
+    ProcessControlBlock *waiting_for_process;
+    unsigned long long int asleep_until;
+};
+
+/*
+ *  Optionals
+ *
+ * in this kernel, an optional can hold a value or an error, but we can't use 
+ * unions here because we need to be able to distinguish errors from results.
+ * this is a little space inefficient, but we'll have to deal with this, or else
+ * we get global errno variables.
+ */
+
+#define CreateOptionalOfType(type)\
+typedef struct Optional##type { \
+    enum error_code error;      \
+    type value;                 \
+} optional_##type
+
+#define has_value(optional) (optional.error == 0)
+#define has_error(optional) (!has_value(optional))
+
+
+typedef unsigned int size_t;
+typedef void* voidptr;
+typedef ProcessControlBlock* pcbptr;
+
+// create optionals for required types
+CreateOptionalOfType(int);
+CreateOptionalOfType(size_t);
+CreateOptionalOfType(pcbptr);
+CreateOptionalOfType(voidptr);
+
+#endif