add progs for lec2

related_info/lec2/Makefile

@@ -0,0 +1,8 @@
+all: hello.c
+	echo "compile and watch the syscalls from hello"
+	gcc -o hello hello.c
+	strace -c ./hello
+	echo "watch the interrupts in linux"
+	more /proc/interrupts
+clean:
+	rm ./hello

related_info/lec2/hello.c

@@ -0,0 +1,5 @@
+#include <stdio.h>
+void main(void)
+{
+  printf("hello world\n");
+}