diff --git a/08_12_thread/2.mymutexthread_st.c b/08_12_thread/2.mymutexthread_st.c
deleted file mode 100644
index 0b15b7e1721f7edb0f52494e49b6bd654c96351d..0000000000000000000000000000000000000000
--- a/08_12_thread/2.mymutexthread_st.c
+++ /dev/null
@@ -1,87 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <pthread.h>
-#include <sys/types.h>
-#include <errno.h>
-
-#include <unistd.h>
-#include <sys/syscall.h> 
-
-void * thread_function(void *);
-
-int Counter=0;
-#ifndef NOMUTEX
-.... mutex_id;
-#endif
-
-int main(void)
-{
-	pthread_t tid1, tid2;
-	void *thread_result;
-
-#ifndef NOMUTEX
-	if(________(&mutex_id, NULL) != 0){
-		perror("pthread_mutex_init");
-		exit(errno);
-	}
-#endif
-
-	if(_______(&tid1, NULL, thread_function, "thread1")!=0) {
-		perror("pthread_create");
-		exit(1);
-	}
-	
-	if(_______(&tid2, NULL, thread_function, "thread2")!=0) {
-		perror("pthread_create");
-		exit(1);
-	}
-	
-	if(_______(tid1, &thread_result)!=0) {
-		perror("pthread_join");
-		exit(1);
-	}
-	if(_______(tid2, &thread_result)!=0) {
-		perror("pthread_join");
-		exit(1);
-	}
-	
-#ifndef NOMUTEX
-	___________(&mutex_id);
-#endif
-
-	printf(" thread result : %s\n", (char *) thread_result);
-	return 0;
-}
-
-void * thread_function(void * arg)
-{
-	int temp;
-	int i, j;
-	char buffer[80];
-
-	printf("thread_function called\n");	
-	for(i=0; i<8; i++) {
-#ifndef NOMUTEX
-		_________(&mutex_id);
-#endif
-		sprintf(buffer, "%s: CountRelay: from %d to ", (char*)arg, Counter);
-		write(1, buffer, strlen(buffer));
-
-		temp=Counter;
-		temp = temp+1;
-// delay
-		for(j=0; j<5000000; j++);
-
-		Counter=temp;
-
-		sprintf(buffer, "%d\n", Counter);
-		write(1, buffer, strlen(buffer));
-		
-#ifndef NOMUTEX
-		__________(&mutex_id);
-#endif
-	}
-	// getchar();
-	_______("thread end");
-}
diff --git a/08_12_thread/README.md b/08_12_thread/README.md
index 87bd6b63fce3a697952614201b79472e5bf49198..bcd87e1f1f905c57e20aefc88bb6a8c27ff1a8cc 100644
--- a/08_12_thread/README.md
+++ b/08_12_thread/README.md
@@ -81,8 +81,11 @@ make
  89
  73
 Main start!
+====sthread1 start====
 합 : 1837, 평균 : 61.233334
+====sthread1 end====
 Main end!
+====sthread2 start====
  1등 : 100
  2등 : 99
  3등 : 96
@@ -113,7 +116,7 @@ Main end!
 28등 : 9
 29등 : 4
 30등 : 1
+====sthread2 end====
 ```
 sthread2가 sthread1보다 연산량이 많아 늦게 끝나는 것을 볼 수 있다.
 
-### 2.mymutexthread.c