diff --git a/student-distrib/paging.c b/student-distrib/paging.c
index 876f419b084d5f50fe34786270bb873a1b8b5ff8..e984fa12260aa14d0bd40dd6ad91e3223e43ee00 100644
--- a/student-distrib/paging.c
+++ b/student-distrib/paging.c
@@ -1,6 +1,5 @@
 #include "paging.h"
 
-
 /* paging_initi(alization)
  * Inputs: void
  * Return Value: void
@@ -17,13 +16,10 @@ void paging_initi(void){
       page_directory[i] = READ_WRITE;
 
       /* 4KB page tables */
-      page_table[i] = (i * 0x1000) | READ_WRITE;
+      page_table[i] = (i * _4_KB) | READ_WRITE;
 
     }
 
-    /* First page table entry need to be 0 */
-    // page_table[0] = 0x0;
-
     /* Set page table for video memory */
     page_table[VIDEO_MEM + 0] |= USER | PRESENT;
     page_table[VIDEO_MEM + 1] |= USER | PRESENT; //for 1st terminal
@@ -43,38 +39,36 @@ void paging_initi(void){
     return;
 }
 
-
-
-
-
-
-//term_id = current
+/* restore_vid_mem
+ * Inputs: none
+ * Return Value: void
+ * Function: restores video memory to actual memory address
+ */
 void restore_vid_mem(void){
-    page_table[0xB8] = (uint32_t)(0xB8000) | USER | READ_WRITE | PRESENT;
+    page_table[VIDEO_MEM] = (uint32_t)(VIDEO_ADDR) | USER | READ_WRITE | PRESENT;
     flush_tlb();
     return;
 }
 
-
-//term_id = ther terminal we want to display
+/* store_vid_mem
+ * Inputs: ID of terminal
+ * Return Value: void
+ * Function: sets video memory according to terminal ID
+ */
 void store_vid_mem(int32_t term_id){
     if(visible_terminal == running_terminal)
 
-        page_table[0xB8] = ((uint32_t)0xB8000) | USER | READ_WRITE | PRESENT;
+        page_table[VIDEO_MEM] = ((uint32_t)VIDEO_ADDR) | USER | READ_WRITE | PRESENT;
 
     else
 
-        page_table[0xB8] = ((uint32_t)(0xB8000 + (term_id+1)*0x1000 )) | USER | READ_WRITE | PRESENT;
+        page_table[VIDEO_MEM] = ((uint32_t)(VIDEO_ADDR + (term_id+1)*_4_KB )) | USER | READ_WRITE | PRESENT;
 
     flush_tlb();
 
     return;
 }
 
-
-
-
-
 /* remap_vidmem
  * Inputs: PID number of process
  * Return Value: void
@@ -82,17 +76,17 @@ void store_vid_mem(int32_t term_id){
  */
 void remap_vidmem()
 {
-    
+    // 33 = 132MB virtual
     page_directory[33] = (uint32_t)(uint32_t)page_table | USER | READ_WRITE | PRESENT;
 
     if(visible_terminal == running_terminal)
-        page_table[0] = ((uint32_t)0xB8000) | USER | READ_WRITE | PRESENT;
+        page_table[0] = ((uint32_t)VIDEO_ADDR) | USER | READ_WRITE | PRESENT;
         
     else
-        page_table[0] = ((uint32_t)(0xB8000 + (running_terminal+1)*0x1000 )) | USER | READ_WRITE | PRESENT;
+        page_table[0] = ((uint32_t)(VIDEO_ADDR + (running_terminal+1)*_4_KB )) | USER | READ_WRITE | PRESENT;
 
     // flush TLB
-	flush_tlb();
+    flush_tlb();
 
     return;
 }
@@ -106,10 +100,11 @@ void remap_program(uint32_t pid){
 
     uint32_t addr = _8_MB + pid * _4_MB;
 
+    // 32 = 128MB virtual 
     page_directory[32] =  addr | SIZE | USER | READ_WRITE | PRESENT;
 
     // flush TLB
-	flush_tlb();
+    flush_tlb();
     return;
 }
 
@@ -125,12 +120,12 @@ void remap_term(int32_t term_id){
     if ( visible_terminal == term_id)
         addr = TERM_VID;
 
-	//page_table[VIDEO_MEM] = addr | USER | READ_WRITE | PRESENT;
+    // 33 = 132MB virtual
     page_directory[33] = ((uint32_t)vid_table) | USER | READ_WRITE | PRESENT ;
     vid_table[VIDEO_MEM] = addr | USER | READ_WRITE | PRESENT;
 
     // flush TLB
-	flush_tlb();
+    flush_tlb();
 
     return;
 }
@@ -142,23 +137,29 @@ void remap_term(int32_t term_id){
  */
 int32_t remap_proc(int32_t pid){
 
-	if (pid < 0 || pid > MAX_PROCESS)
+    if (pid < 0 || pid > MAX_PROCESS)
         return -1;
 
-	page_directory[32] = (_8_MB + _4_MB * pid) | SIZE | USER | READ_WRITE | PRESENT;
+    // 32 = 128MB virtual 
+    page_directory[32] = (_8_MB + _4_MB * pid) | SIZE | USER | READ_WRITE | PRESENT;
 
     // flush TLB
-	flush_tlb();
-	return 0;
+    flush_tlb();
+    return 0;
 }
 
+/* flush_tlb
+ * Inputs: void
+ * Return Value: void
+ * Function: flushes the TLB (used when changing paging)
+ */
 void flush_tlb(void){
     asm volatile(
-		"movl %%cr3, %%eax    \n"
-		"movl %%eax, %%cr3    \n"
-		:
-		: 
-		: "memory", "cc"
-	);
+        "movl %%cr3, %%eax    \n"
+        "movl %%eax, %%cr3    \n"
+        :
+        : 
+        : "memory", "cc"
+    );
     return;
 }
diff --git a/student-distrib/pit.c b/student-distrib/pit.c
index 49316dbe7be1812a725421297b71665766ca4de7..cbdb07f6b1077a9d04fe41555825d175ea68a89b 100644
--- a/student-distrib/pit.c
+++ b/student-distrib/pit.c
@@ -1,21 +1,30 @@
 #include "pit.h"
 
-// referance from https://wiki.osdev.org/PIT
-void i8253_init(void){
-	int32_t freq = FREQUENCY / 100;
-	int32_t low  = freq &  0xFF;
-	int32_t high = freq >> 8;
+// reference from https://wiki.osdev.org/PIT
 
-	//sent command to the port
-	outb(0x34,  CMD_REG);
-	outb(low,   CHANNEL_0);
-	outb(high, CHANNEL_0);
-	enable_irq(0);
+/* i8253_init
+ * Inputs: void
+ * Return Value: void
+ * Function: initializes pit
+ */
+void i8253_init(void){
+    int32_t freq = FREQUENCY / 100; // interrupt every 10ms
+    int32_t low  = freq &  0xFF;    // 0xFF = mask (send lower 8 bits)
+    int32_t high = freq >> 8;       // (send higher 8 bits)
+
+    //send command to the port
+    outb(0x34, CMD_REG);           // 0x34 is port in PIC for PIT
+    outb(low,  CHANNEL_0);
+    outb(high, CHANNEL_0);
+    enable_irq(PIT_IRQ);
     return;
 }
 
-
-
+/* pit_handler
+ * Inputs: void
+ * Return Value: void
+ * Function: pit interrupt handler
+ */
 void pit_handler(void)
 {
 
diff --git a/student-distrib/pit.h b/student-distrib/pit.h
index 8ef28a9a7c13b9dfff89ef23f31686c6fa20d9fe..432c77739057d19a266b2f6e3ed66c1858d5e073 100644
--- a/student-distrib/pit.h
+++ b/student-distrib/pit.h
@@ -5,6 +5,7 @@
 #define FREQUENCY 			    1193182
 #define CHANNEL_0 				0x40
 #define CMD_REG					0x43
+#define PIT_IRQ                 0x00
 
 void i8253_init(void);
 void pit_handler(void);
diff --git a/student-distrib/scheduler.c b/student-distrib/scheduler.c
index 9208c60a016fbfe5944831c3d4e8574be7e1151d..a2cf7019df20a4dca2dd4ee84c021b813b0e0f98 100644
--- a/student-distrib/scheduler.c
+++ b/student-distrib/scheduler.c
@@ -32,7 +32,7 @@ void scheduler(void){
 
         printf("terminal = %d\n", running_terminal);
 
-        send_eoi(0);
+        send_eoi(PIT_IRQ);
 
         execute((uint8_t *)"shell");
     }
@@ -50,7 +50,7 @@ void scheduler(void){
 
     if(terminal[running_terminal].pcb == NULL)
     {
-        send_eoi(0);
+        send_eoi(PIT_IRQ);
         return;
     }
 
@@ -65,7 +65,7 @@ void scheduler(void){
     tss.ss0 = KERNEL_DS;
     tss.esp0 = _8_MB - _8_KB * (next_pcb->pid);
 
-    send_eoi(0);
+    send_eoi(PIT_IRQ);
 
     asm volatile(
         //change esp and ebp
diff --git a/student-distrib/scheduler.h b/student-distrib/scheduler.h
index f26885a5c58c66d979ec9bc2e5d318c52808df66..ae122f10e0da206de27143b6008447525c033eb2 100644
--- a/student-distrib/scheduler.h
+++ b/student-distrib/scheduler.h
@@ -1,7 +1,7 @@
 #include "lib.h"
 #include "types.h"
 #include "x86_desc.h"
-
+#include "pit.h"
 
 extern void scheduler(void);