diff --git a/include/kernel.h b/include/kernel.h
index 73c0551..aaba988 100644
--- a/include/kernel.h
+++ b/include/kernel.h
@@ -1,5 +1,7 @@
 /* kernel.h */
 
+/* avr specific values. Original saved under orig/ folder */
+
 /* General type declarations used throughout the kernel */
 
 typedef	unsigned char	byte;
@@ -12,27 +14,15 @@ typedef	unsigned long long uint64;
 
 /* Xinu-specific types */
 
-// typedef	int32	sid32;		/* semaphore ID				*/
-// typedef	int16	qid16;		/* queue ID				*/
-// typedef	int32	pid32;		/* process ID				*/
-// typedef	int32	did32;		/* device ID				*/
 typedef	int16	pri16;		/* process priority			*/
 typedef	uint32	umsg32;		/* message passed among processes	*/
 typedef	int32	bpid32;		/* buffer pool ID			*/
 typedef	byte	bool8;		/* Boolean type				*/
-// typedef	uint32	intmask;	/* saved interrupt mask			*/
-// typedef	int32	ibid32;		/* index block ID (used in file system)	*/
-// typedef	int32	dbid32;		/* data block ID (used in file system)	*/
-// typedef	int32	uid32;		/* ID for UDP table descriptor		*/
 
 typedef	char	sid32;		/* semaphore ID				*/
 typedef	char	qid16;		/* queue ID				*/
 typedef	char	pid32;		/* process ID				*/
 typedef	char	did32;		/* device ID				*/
-// RAFA typedef	char	pri16;		/* process priority			*/
-// RAFA typedef	char	umsg32;		/* message passed among processes	*/
-// RAFA typedef	char	bpid32;		/* buffer pool ID			*/
-// RAFA typedef	byte	bool8;		/* Boolean type				*/
 typedef	char	intmask;	/* saved interrupt mask			*/
 typedef	char	ibid32;		/* index block ID (used in file system)	*/
 typedef	char	dbid32;		/* data block ID (used in file system)	*/
@@ -40,18 +30,12 @@ typedef	char	uid32;		/* ID for UDP table descriptor		*/
 
 /* Function declaration return types */
 
-// typedef int32	syscall;	/* system call declaration		*/
-// typedef int32	devcall;	/* device call declaration		*/
-// typedef int32	shellcmd;	/* shell command declaration		*/
 typedef int32	process;	/* top-level function of a process	*/
 typedef	void	interrupt;	/* interrupt procedure			*/
-// typedef	int32	status;		/* returned status value (OK/SYSERR)	*/
 
 typedef char	syscall;	/* system call declaration		*/
 typedef char	devcall;	/* device call declaration		*/
 typedef char	shellcmd;	/* shell command declaration		*/
-// RAFA typedef char	process;	/* top-level function of a process	*/
-// RAFA typedef	void	interrupt;	/* interrupt procedure			*/
 typedef	char	status;		/* returned status value (OK/SYSERR)	*/
 
 #define local	static		/* Local procedure or variable declar.	*/
@@ -76,8 +60,6 @@ typedef	char	status;		/* returned status value (OK/SYSERR)	*/
 
 extern	qid16	readylist;	/* global ID for list of ready processes*/
 
-// RAFA #define	MINSTK	400		/* minimum stack size in bytes		*/
-// #define	MINSTK	256		/* minimum stack size in bytes		*/
 #define	MINSTK	64		/* minimum stack size in bytes		*/
 
 #define	CONTEXT	64		/* bytes in a function call context on	*/
@@ -86,7 +68,6 @@ extern	qid16	readylist;	/* global ID for list of ready processes*/
 
 /* Size of the stack for the null process */
 
-// #define	NULLSTK		4096	/* stack size for null process		*/
 #define	NULLSTK		256	/* stack size for null process		*/
 
 /* Prototypes of I/O functions used throughout the kernel */
diff --git a/include/mark.h b/include/mark.h
index 72a6457..44b5999 100644
--- a/include/mark.h
+++ b/include/mark.h
@@ -1,6 +1,7 @@
 /* mark.h - notmarked */
 
-// RAFA #define	MAXMARK	20		/* Maximum number of marked locations	*/
+/* avr specific values. Original saved under orig/ folder */
+
 #define	MAXMARK	10		/* Maximum number of marked locations	*/
 
 extern	int32	*(marks[]);
diff --git a/include/memory.h b/include/memory.h
index fce2cfc..b3a9d98 100644
--- a/include/memory.h
+++ b/include/memory.h
@@ -1,5 +1,7 @@
 /* memory.h - roundmb, truncmb, freestk */
 
+/* avr specific values. Original saved under orig/ folder */
+
 #define	PAGE_SIZE	1024 // TODO: unused?
 
 /*----------------------------------------------------------------------
@@ -25,14 +27,3 @@ struct	memblk	{			/* See roundmb & truncmb	*/
 extern	struct	memblk	memlist;	/* Head of free memory list	*/
 extern	void	*minheap;		/* Start of heap		*/
 extern	void	*maxheap;		/* Highest valid heap address	*/
-
-
-/* Added by linker */
-
-// extern	uint32	text;			/* Start of text segment	*/
-// extern	uint32	etext;			/* End of text segment		*/
-// extern	uint32	data;			/* Start of data segment	*/
-// extern	uint32	edata;			/* End of data segment		*/
-// extern	uint32	bss;			/* Start of bss segment		*/
-// extern	uint32	ebss;			/* End of bss segment		*/
-// extern	uint32	end;			/* End of program		*/
diff --git a/include/orig/kernel.h b/include/orig/kernel.h
new file mode 100644
index 0000000..718e486
--- /dev/null
+++ b/include/orig/kernel.h
@@ -0,0 +1,73 @@
+/* kernel.h */
+
+/* General type declarations used throughout the kernel */
+
+typedef	unsigned char	byte;
+typedef	unsigned char	uint8;
+typedef	int		int32;
+typedef	short		int16;
+typedef	unsigned int	uint32;
+typedef	unsigned short	uint16;
+typedef	unsigned long long uint64;
+
+/* Xinu-specific types */
+
+typedef	int32	sid32;		/* semaphore ID				*/
+typedef	int16	qid16;		/* queue ID				*/
+typedef	int32	pid32;		/* process ID				*/
+typedef	int32	did32;		/* device ID				*/
+typedef	int16	pri16;		/* process priority			*/
+typedef	uint32	umsg32;		/* message passed among processes	*/
+typedef	int32	bpid32;		/* buffer pool ID			*/
+typedef	byte	bool8;		/* Boolean type				*/
+typedef	uint32	intmask;	/* saved interrupt mask			*/
+typedef	int32	ibid32;		/* index block ID (used in file system)	*/
+typedef	int32	dbid32;		/* data block ID (used in file system)	*/
+typedef	int32	uid32;		/* ID for UDP table descriptor		*/
+
+/* Function declaration return types */
+
+typedef int32	syscall;	/* system call declaration		*/
+typedef int32	devcall;	/* device call declaration		*/
+typedef int32	shellcmd;	/* shell command declaration		*/
+typedef int32	process;	/* top-level function of a process	*/
+typedef	void	interrupt;	/* interrupt procedure			*/
+typedef	int32	status;		/* returned status value (OK/SYSERR)	*/
+
+#define local	static		/* Local procedure or variable declar.	*/
+
+/* Boolean constants */
+
+#define FALSE	0		/* Boolean False			*/
+#define TRUE	1		/* Boolean True				*/
+
+/* Null pointer, character, and string definintions */
+
+#define NULL	0		/* null pointer for linked lists	*/
+#define NULLCH	'\0'		/* null character			*/
+#define	NULLSTR	""		/* null string				*/
+
+/* Universal return constants */
+
+#define OK	( 1)		/* normal system call return		*/
+#define	SYSERR	(-1)		/* system call failed			*/
+#define	EOF	(-2)		/* End-of-file (usually from read)	*/
+#define	TIMEOUT	(-3)		/* system call timed out		*/
+
+extern	qid16	readylist;	/* global ID for list of ready processes*/
+
+#define	MINSTK	400		/* minimum stack size in bytes		*/
+
+#define	CONTEXT	64		/* bytes in a function call context on	*/
+				/* the run-time stack			*/
+#define	QUANTUM	2		/* time slice in milliseconds		*/
+
+/* Size of the stack for the null process */
+
+#define	NULLSTK		8192	/* stack size for null process		*/
+
+/* Prototypes of I/O functions used throughout the kernel */
+
+syscall	kprintf(char *fmt, ...);
+syscall	kputc(byte);
+syscall	kgetc(void);
diff --git a/include/orig/mark.h b/include/orig/mark.h
new file mode 100644
index 0000000..2579015
--- /dev/null
+++ b/include/orig/mark.h
@@ -0,0 +1,16 @@
+/* mark.h - notmarked */
+
+#define	MAXMARK	20		/* Maximum number of marked locations	*/
+
+extern	int32	*(marks[]);
+extern	int32	nmarks;
+extern	sid32	mkmutex;
+typedef	int32	memmark[1];	/* Declare a memory mark to be an array	*/
+				/*   so user can reference the name	*/
+				/*   without a leading &		*/
+
+/*------------------------------------------------------------------------
+ *  notmarked  -  Return nonzero if a location has not been marked
+ *------------------------------------------------------------------------
+ */
+#define	notmarked(L)		(L[0]<0 || L[0]>=nmarks || marks[L[0]]!=L)
diff --git a/include/orig/memory.h b/include/orig/memory.h
new file mode 100644
index 0000000..7916cf9
--- /dev/null
+++ b/include/orig/memory.h
@@ -0,0 +1,38 @@
+/* memory.h - roundmb, truncmb, freestk */
+
+#define	PAGE_SIZE	4096
+
+/*----------------------------------------------------------------------
+ * roundmb, truncmb - Round or truncate address to memory block size
+ *----------------------------------------------------------------------
+ */
+#define	roundmb(x)	(char *)( (7 + (uint32)(x)) & (~7) )
+#define	truncmb(x)	(char *)( ((uint32)(x)) & (~7) )
+
+/*----------------------------------------------------------------------
+ *  freestk  --  Free stack memory allocated by getstk
+ *----------------------------------------------------------------------
+ */
+#define	freestk(p,len)	freemem((char *)((uint32)(p)		\
+				- ((uint32)roundmb(len))	\
+				+ (uint32)sizeof(uint32)),	\
+				(uint32)roundmb(len) )
+
+struct	memblk	{			/* See roundmb & truncmb	*/
+	struct	memblk	*mnext;		/* Ptr to next free memory blk	*/
+	uint32	mlength;		/* Size of blk (includes memblk)*/
+	};
+extern	struct	memblk	memlist;	/* Head of free memory list	*/
+extern	void	*minheap;		/* Start of heap		*/
+extern	void	*maxheap;		/* Highest valid heap address	*/
+
+
+/* Added by linker */
+
+extern	int	text;			/* Start of text segment	*/
+extern	int	etext;			/* End of text segment		*/
+extern	int	data;			/* Start of data segment	*/
+extern	int	edata;			/* End of data segment		*/
+extern	int	bss;			/* Start of bss segment		*/
+extern	int	ebss;			/* End of bss segment		*/
+extern	int	end;			/* End of program		*/