as of 2013-12-062013-12-06

26 files changed, 163 insertions, 114 deletions

diff --git a/com.c b/com.c
index 1d21a0a..d996e66 100644
--- a/com.c
+++ b/com.c
@@ -3,7 +3,8 @@
  * CSI350 Operating Systems

  * Fall 2013

  * Averill Morash, Ben Burwell

- * COM.C

+ *

+ * File: com.c

  */

 

 #include <dos.h>

@@ -16,6 +17,7 @@ void interrupt (*vect0c)();
 

 int com_opened;

 

+// Open the com port

 int com_open(int * flag, int rate) {

   unsigned char imr;

   unsigned char mcr;

@@ -24,13 +26,15 @@ int com_open(int * flag, int rate) {
 

   disable();

 

+  // Ensure com has not already been opened, if

+  // it has, we must return.

   if (com_opened == NULL || com_opened == 0) {

 	com_opened = 1;

   } else {

 	return -2;

   }

 

-  // modify the interrupt vector table

+  // Modify the interrupt vector table

   vect0c = getvect(0x0c);

   setvect(0x0c, &com_int);

 

@@ -48,6 +52,7 @@ int com_open(int * flag, int rate) {
   // 1843200 / (1200 * 16) = 96 = 0x0060

   // So the MSB is 0x00 and the LSB is 0x60

 

+  // Ensure baud rate is valid

   if (rate != 1200) {

 	return -3;

   }

@@ -97,17 +102,27 @@ int com_open(int * flag, int rate) {
   return 0;

 }

 

+// Com Close

 void com_close() {

   disable();

+

+  // restore MS-DOS com vector

   setvect(0x0c, vect0c);

+

   enable();

 }

 

+// Interrupt handler

 void interrupt com_int() {

   int iir;

   int *lst_stk;

-  int ret = 0; //0 indicates not finished, 1 indicated finshed

 

+  // 0 indicates not finished, 1 indicated finshed

+  int ret = 0;

+

+  disable();

+

+  // save base pointer

   lst_stk = _BP;

 

   // check IIR to see what caused the interrupt

@@ -120,10 +135,11 @@ void interrupt com_int() {
   } else if (iir == 0x04) { // 0000-0100

 	ret = com_read_int();

   } else {

-	// something is wrong

+	// interrupt was not read or write

 	return;

   }

 

+  // if the operation is done, call IO_complete

   if (ret == 1) {

 	IO_complete(COM, lst_stk);

   }

@@ -131,70 +147,92 @@ void interrupt com_int() {
   // write end of interrupt to 8259

   outportb(0x20, 0x20);

 

+  enable();

   return;

 

 }

 

+// Read from the com port

 int com_read(char far * buffer, int far * length) {

 

   char dq;

   int i;

 

+  disable();

+

+  // if we haven't yet opened com, we can't proceed

   if (&com == NULL) {

-	// com not yet open

+	enable();

 	return -1;

   }

 

   // check for invalid length

   if (*length < 1) {

+	enable();

 	return -3;

   }

 

   // check if DCB is free

   if (com.current_op != NO_OP) {

 	// previous IO not yet complete

-	// TODO: we should block this process

+	enable();

 	return -2;

   }

 

+  if (buffer == NULL || length == NULL) {

+	printf("error in com_read\n");

+	enable();

+	return;

+  }

+  // set up the DCB

   com.buffer = buffer;

   com.length = length;

   com.current_op = READ_OP;

   com.count = 0;

 

+  // clear the buffer

   strcpy(buffer, "");

 

+  // now we need to use the ring buffer to place typed-ahead

+  // characters into the buffer

+

+  // keep track of how many characters are copied from the

+  // ring buffer.

   i = 0;

 

   while (com.ring_count > 0 && strlen(buffer) < *length) {

-

 	dq = dcb_dequeue(&com);

-	//strcat(buffer, &dq);

 	buffer[i] = dq;

 	i++;

   }

 

+  // place a null character at the end of the buffer

   buffer[i] = '\0';

   com.count = i;

 

+  enable();

   return 0;

 }

 

 int com_write(char far * buffer, int far * length) {

   int ier;

 

+  disable();

   // check that com has been initialized

   if (&com == NULL) {

+	enable();

 	return -1;

   }

 

   // check that com is not busy

   if (com.current_op != NO_OP) {

+	enable();

 	return -2;

   }

 

   // check that the length is valid

   if (*length < 1) {

+	enable();

 	return -3;

   }

 

@@ -210,6 +248,7 @@ int com_write(char far * buffer, int far * length) {
   ier = ier | 0x02;

   outportb(IER, ier);

 

+  enable();

   return 0;

 }

 

diff --git a/comhan.c b/comhan.c
index 8506ef4..9e6c03a 100644
--- a/comhan.c
+++ b/comhan.c
@@ -22,36 +22,32 @@
 #define PROMPT         5

 #define ALIAS          6

 #define SHOW           7

-#define ALLOCATE       8

-#define CMD_FREE       9

-#define CMD_LOAD      10

-#define CMD_RESUME    11

-#define CMD_RUN       12

-#define CMD_SUSPEND   13

-#define CMD_TERMINATE 14

-#define CMD_SETPRI    15

-#define CMD_DISPATCH  16

-#define CLOCK     17

-

-#define NUM_CMDS 18

-

-int length;             /* Length of the command line.      */

+#define CMD_LOAD       8

+#define CMD_RESUME     9

+#define CMD_RUN       10

+#define CMD_SUSPEND   11

+#define CMD_TERMINATE 12

+#define CMD_SETPRI    13

+#define CLOCK     14

+

+#define NUM_CMDS 15

+

+int length = 1;         /* Length of the command line.      */

 unsigned sp_save;       /* A stack save for mod 4 dispatch. */

 

 char prompt[20] = "mpx>";

-const char version[] = "MPX OS - Version 1.0\n";

+const char version[] = "MPX-OS 2013 ZOMBIE Edition (v.1010372365424) \n";

 char date[] = "01/09/1991";

 

 char *cmds[] = { "version", "date", "directory", "stop",

 				 "help", "prompt", "alias", "show",

-				 "allocate", "free", "load", "resume",

+				 "load", "resume",

 				 "run", "suspend", "terminate", "setpriority",

-				 "dispatch", "clock", NULL};

+				 "clock", NULL};

 char *aliases[] = {"        ", "        ", "        ", "        ",

 				   "        ", "        ", "        ", "        ",

 				   "        ", "        ", "        ", "        ",

-				   "        ", "        ", "        ", "        ",

-				   "        ", "        ", NULL};

+				   "        ", "        ", "        ", NULL};

 

 /*

  *   comhan()    This is the command handler for the MPX OS.

@@ -68,13 +64,18 @@ void comhan() {
 	static char buffer[BUF_SIZE];

 	int do_stop = 0;

 

+	// Occasionally the first con_read request recieves an empty response

+	// Make a dummy request to compensate

+	sys_req(CON, READ, buffer, &length);

+

 	do {

 	  printf("%s ",prompt);              /* Print a prompt.         */

-	  //length = 4; //mpx>

-	  //sys_req(COM, WRITE, prompt, &length);

 	  length = BUF_SIZE;                 /* Reset length of buffer. */

 	  sys_req(CON,READ,buffer,&length);  /* Request CON input       */

 

+	  // For better display, print a newline after user input

+	  printf("\n");

+

 	  set_args(buffer, args);

 

 	  switch (get_cmd(args[0])) {

@@ -86,15 +87,12 @@ void comhan() {
 		case PROMPT:        cmd_prompt(args);     break;

 		case ALIAS:         cmd_alias(args);      break;

 		case SHOW:          cmd_show(args);       break;

-//		case ALLOCATE:      cmd_allocate(args);   break;

-//		case CMD_FREE:      cmd_free(args);       break;

 		case CMD_LOAD:      cmd_load(args);       break;

 		case CMD_RESUME:    cmd_resume(args);     break;

 		case CMD_RUN:       cmd_run(args);        break;

 		case CMD_SUSPEND:   cmd_suspend(args);    break;

 		case CMD_TERMINATE: cmd_terminate(args);  break;

 		case CMD_SETPRI:    cmd_setpri(args);     break;

-//		case CMD_DISPATCH:  cmd_dispatch();       break;

 		case CLOCK:         cmd_clock(args);      break;

 		default:

 		  printf("Can't recognize. %s\n", args[0]);

@@ -128,8 +126,7 @@ int get_cmd(char cmd[]){
 int set_args(char buffer[], char *args[]) {

   /* use string tok to set the contents of args from buffer

 	 and return the number of args (will go into argc) */

-  char separators[5] = " /,:"; //Characters that separate tokens

-  // TODO: put = back in separators

+  char separators[6] = " /,:="; //Characters that separate tokens

   int i = 0; //loop control

 

   args[i] = strtok(buffer, separators); //Get first token

@@ -202,6 +199,7 @@ int cmd_stop(){
   sys_req(CON,READ,buffer,&length);

 

   if (strcmp(buffer, "y") == 0 || strcmp(buffer, "Y") == 0) {

+	disable();

 	do {

 	  if(p->type != FREE) {

 		freemem(p->loadaddr);

@@ -209,6 +207,7 @@ int cmd_stop(){
 	  }

 	  p = p->chain;

 	} while(p != NULL);

+	enable();

 	sys_exit();

 	printf("** COMHAN execution complete **\n");

 	return 1;

@@ -234,17 +233,18 @@ void cmd_help(char *args[]) {
   help[PROMPT]        = "prompt string        Change the prompt for commands";

   help[ALIAS]         = "alias command=string Create an alias for a command";

   help[SHOW]          = "show                 Prints PCB information";

-  help[ALLOCATE]      = "allocate             Builds PCB with specified options";

-  help[CMD_FREE]      = "free name            Frees the PCB called name";

   help[CMD_LOAD]      = "load name[=ppp]      Creates a process called name with priority ppp";

   help[CMD_RESUME]    = "resume name          Resumes the process called name";

   help[CMD_RUN]       = "run name[=ppp]       Runs a process called name with priority ppp";

   help[CMD_SUSPEND]   = "suspend name         Suspends the process called name";

   help[CMD_TERMINATE] = "terminate name       Terminates the process called name";

   help[CMD_SETPRI]    = "setpriority name=ppp Sets the priority of process name";

-  help[CMD_DISPATCH]  = "dispatch             Runs each process once";

   help[CLOCK]         = "clock [stop|start]   Perform clock operations";

 

+  if (args[1] != NULL && get_cmd(args[1]) < 0) {

+	printf("Not a valid command.\n");

+	return;

+  }

   // print header

   printf(               "  Name                 Use \n");

   printf(               "  ==================== ================================================= \n");

@@ -294,6 +294,8 @@ void print_pcb(pcb * p) {
 		str[1] = 'o';

 	} else if (p->state == BLOCKED) {

 		str[1] = 'b';

+	} else if (p->state == ZOMBIE) {

+		str[1] = 'z';

 	} else {

 		str[1] = '-';

 	}

@@ -308,7 +310,7 @@ void print_pcb(pcb * p) {
 

 	str[3] = '\0';

 

-	printf("0x%04x %8s %s 0x%04x 0x%04x 0x%04x %3d 0x%04x \n",

+	printf("0x%04x %8s %s 0x%04x 0x%04x 0x%04x %4d 0x%04x \n",

 		  p, p->name, str, p->chain, p->prev,

 		  p->next, p->priority, p->loadaddr);

 }

@@ -322,12 +324,12 @@ void cmd_show(char *args[]) {
 	return;

   }

 

-  printf("PCB_Ad Name     TSP chain  prev   next   pri l_addr \n");

-  printf("------ -------- --- ------ ------ ------ --- ------ \n");

+  printf("PCB_Ad Name     TSP chain  prev   next    pri l_addr \n");

+  printf("------ -------- --- ------ ------ ------ ---- ------ \n");

 

   if (strcmp(args[1], "init") == 0 || strcmp(args[1], "ready") == 0) {

 	disable();

-	current = (strcmp(args[1], "init") == 0)? io_init_queue : ready_queue_locked;

+	current = (strcmp(args[1], "init") == 0)? io_init_queue_locked : ready_queue_locked;

 	enable();

 

 	if (current == NULL) {

@@ -368,7 +370,7 @@ void cmd_show(char *args[]) {
  * Load

  */

 void cmd_load(char *args[]) {

-  int i, ret, priority = 0;

+  int i, priority = 0;

   unsigned segp;

   pcb *p;

   int paragraphs;

@@ -514,19 +516,10 @@ void cmd_terminate(char *args[]) {
    if (strcmp(args[1], "*") == 0) {

 	 p = pcb_list;

 	 do {

+	   // Set all application processes to ZOMBIE state

+	   // They will be terminated in dispatch()

 	   if (p->type == APP_PROCESS) {

-		 // remove from queue as needed

-		 disable();

-		 if (p->state == READY) {

-		   remove_pcb(&ready_queue_locked, p);

-		 } else if (p->state == BLOCKED) {

-		   remove_pcb(&io_init_queue, p);

-		 }

-		 enable();

-

-		 // free it

-		 freemem(p->loadaddr);

-		 free_pcb(pcb_list, p);

+		 p->state = ZOMBIE;

 	   }

 	   p = p -> chain;

 	 } while (p != NULL);

@@ -535,19 +528,7 @@ void cmd_terminate(char *args[]) {
 	 p = search_pcb(pcb_list, args[1]);

 

 	 if (p != NULL && p->type == APP_PROCESS) {

-

-	   disable();

-	   // remove from queue as needed

-	   if (p->state == READY) {

-		 remove_pcb(&ready_queue_locked, p);

-	   } else if (p->state == BLOCKED) {

-		 remove_pcb(&io_init_queue, p);

-	   }

-	   enable();

-

-	   // free it

-	   freemem(p->loadaddr);

-	   free_pcb(pcb_list, p);

+	   p->state = ZOMBIE;

 	 } else {

 	   printf("No process with the specified name. \n");

 	 }

diff --git a/io.c b/io.c
index aa9b027..f5bf17a 100644
--- a/io.c
+++ b/io.c
@@ -9,14 +9,13 @@
 #include <stdio.h>

 #include "mpx.h"

 

-#define DS_OFFSET   6 // was 3 before

+#define DS_OFFSET   6

 

-int count = 0;

 void IO_sup(pcb *p) {

-  char far *buffer;

-  int far *length;

-  unsigned *ds_add;

-  int con_w = 0;

+  char far *buffer;  // far pointer to the io buffer

+  int far *length;   // far pointer to an int representing length of the io buffer

+  unsigned *ds_add;  // data segment address

+  int con_w = 0;     // flag for if the request was a con_write request

   int rc;

 

   disable();

@@ -69,6 +68,9 @@ void IO_sup(pcb *p) {
   // put the pcb back in the ready queue, if it was a con_write

   if (con_w == 1) {

 	insert_pcb(&ready_queue_locked, p,0);

+	p->state = READY;

+  } else {

+	p->state = BLOCKED;

   }

   enable();

   return;

@@ -81,9 +83,14 @@ int IO_complete(int device, int *stk_ptr) {
   dcb *d;

 

   disable();

+  // get the dcb for the requested device

   switch (device){

 	case CON:

 	  d = &con;

+	  // the con dcb isn't managed by con drive

+	  // so we need to reset it here, but the

+	  // other dcbs are handled in those files

+	  // before calling io_complete

 	  d->current_op = NO_OP;

 	  break;

 	case COM:

@@ -111,20 +118,32 @@ int IO_complete(int device, int *stk_ptr) {
   // insert into ready queue

   insert_pcb(&ready_queue_locked, current, 0);

 

-  // set its state to ready

-  current->state = READY;

+  // set its state to ready, unless it became

+  // a zombie while it was waiting for io to complete

+  if (current->state != ZOMBIE) {

+	current->state = READY;

+  }

 

-  if (strcmp(d->current_pcb->name, "iocom2")==0) {

-	count++;

-	if (count > 20) {

-	d = &com;

+  if (io_init_queue_locked != NULL) {

+	// if there are pending IO requests schedule them

+	current = io_init_queue_locked;

+	while (current != NULL && current->parm_add->op_number != device) {

+	  current = current->next;

+	}

+

+	if (current != NULL) {

+	  // take the pcb out of the io_init queue

+	  remove_pcb(&io_init_queue_locked, current);

+

+	  // if it wasn't terminated while waiting for io...

+	  if (current->state != ZOMBIE) {

+		// ... schedule the io

+		IO_sched(current);

+	  } else {

+		// send the zombie back to be ... dispatched ... muahaha

+		insert_pcb(&ready_queue_locked, current, 0);

+	  }

 	}

-  }

-  if (d->pcb_head != NULL) {

-	// if there are pending IO requests for this device

-	//schedule them (IO_sched)

-	remove_pcb(&(d->pcb_head), d->pcb_head);

-	IO_sched(d->pcb_head);

   }

 

   outportb(0x20,0x20); // EOI signal

@@ -145,6 +164,7 @@ int IO_sched(pcb *p) {
   int op_num;

   int op_type;

 

+  disable();

   if (DEBUG_PRINTS) {printf("in io sched\n");}

 

   // determine which device is requested

@@ -176,17 +196,18 @@ int IO_sched(pcb *p) {
 	  return -2;

   }

 

+  // If the device is busy

   if (d->current_op != NO_OP) {

 	disable();

 	// put pcb in IO queue

-	insert_pcb(&(d->pcb_head), p, 1);

-	// take pcb out of ready q

-	remove_pcb(&ready_queue_locked, p);

+	insert_pcb(&io_init_queue_locked, p, 1);

+	p->state = BLOCKED;

 	enable();

   } else {

+	// If the device wasn't busy, start the io

 	d->current_pcb = p;

 	IO_sup(p);

   }

-

+  enable();

   return 0;

 }

diff --git a/main.c b/main.c
index 41269bf..020ab05 100644
--- a/main.c
+++ b/main.c
@@ -11,7 +11,7 @@
 

 pcb * pcb_list;

 pcb * ready_queue_locked;

-pcb * io_init_queue;

+pcb * io_init_queue_locked;

 pcb * cop;

 

 pcb pcb0;

@@ -38,7 +38,6 @@ unsigned sys_stack[STACK_SIZE];
 

 int main(void) {

 	pcb * pcb_addr;

-	int rc;

 	dcb * d = &con;//test

 	char *args[] = {"load", "idle"};

 

@@ -88,7 +87,7 @@ int main(void) {
 

 	// set up command handler as a PCB

 	pcb_addr = get_pcb(pcb_list);

-	rc = build_pcb(pcb_addr, "ComHan", SYS_PROCESS, READY, NOT_SUSPENDED, 127, _CS,

+	build_pcb(pcb_addr, "ComHan", SYS_PROCESS, READY, NOT_SUSPENDED, 127, _CS,

 	  (unsigned)comhan, _DS, 0x200);

 

 	disable();

@@ -106,7 +105,7 @@ int main(void) {
 	// update priority for idle process

 	// we can't do this when initially calling because of

 	// APP_PROCESS type priority validation

-	pcb_addr = search_pcb(&pcb_list, "idle");

+	pcb_addr = search_pcb(pcb_list, "idle");

 	pcb_addr->priority = -128;

 	pcb_addr->suspend = NOT_SUSPENDED;

 	pcb_addr->type = SYS_PROCESS;

diff --git a/mpx.h b/mpx.h
index 3a9ad85..09f1ac7 100644
--- a/mpx.h
+++ b/mpx.h
@@ -54,6 +54,7 @@ typedef struct parmstruct parm;
 #define READY         0

 #define RUNNING       1

 #define BLOCKED       2

+#define ZOMBIE        3

 #define NOT_SUSPENDED 0

 #define SUSPENDED     1

 #define STACK_SIZE  900

@@ -227,7 +228,7 @@ extern dir direct[];  /* Array of directory entries -     see direct.c */
 extern int directory(dir *direct, int dir_size);

 extern pcb * pcb_list;

 extern pcb * ready_queue_locked;

-extern pcb * io_init_queue;

+extern pcb * io_init_queue_locked;

 extern pcb * cop; /* The currently operating process. */

 extern unsigned sys_stack[];

 extern unsigned sp_save; /* So that mod 4 can return to cmd_dispatch */

diff --git a/pcb.c b/pcb.c
index c69dd87..1375ae0 100644
--- a/pcb.c
+++ b/pcb.c
@@ -126,12 +126,10 @@ int insert_pcb(pcb **queue, pcb * addr, int method) {
   pcb * current = *queue;

   pcb * one_after;

 

-  disable();

 

   // if there's nothing in the queue yet, make the PCB the start

   if (current == NULL) {

 	*queue = addr;

-	enable();

 	return 1;

   }

 

@@ -147,7 +145,6 @@ int insert_pcb(pcb **queue, pcb * addr, int method) {
 	current->next = addr;

 	addr->next = NULL;

 	addr->prev = current;

-	enable();

 	return 1;

   } else if (method == 0) {

 	// insert in priority order

@@ -176,10 +173,8 @@ int insert_pcb(pcb **queue, pcb * addr, int method) {
 	  addr->next = current;

 	  *queue = addr;

 	}

-	enable();

 	return 1;

   } else {

-	enable();

 	// There was a problem, return error code

 	return -1;

   }

@@ -191,7 +186,11 @@ int insert_pcb(pcb **queue, pcb * addr, int method) {
 int remove_pcb(pcb **queue, pcb * addr) {

   pcb * current = *queue;

 

-  disable();

+  if (addr == NULL || *queue == NULL) {

+	printf("bad times ahead \n");

+	return;

+  }

+

   // are we removing the head?

   if (addr == *queue) {

 	*queue = addr->next;

@@ -215,6 +214,5 @@ int remove_pcb(pcb **queue, pcb * addr) {
 	}

 	current = current->next;

   } while (current != NULL);

-  enable();

   return -1;

 }

diff --git a/printer.c b/printer.c
index 6eab61e..60e96e3 100644
--- a/printer.c
+++ b/printer.c
@@ -15,7 +15,6 @@ int prt_opened;
 

 int prt_open(int * prt_flag) {

   unsigned char imr;

-  unsigned char pcr;

 

   disable();

 

@@ -48,7 +47,6 @@ int prt_open(int * prt_flag) {
 }

 

 int prt_write(char far *buffer, int far *length) {

-  unsigned char pcr;

 

   disable();

   // check that prt isn't busy

@@ -89,7 +87,6 @@ int prt_write(char far *buffer, int far *length) {
 }

 

 int prt_close() {

-  unsigned char pcr;

   unsigned char imr;

 

   disable();

@@ -114,8 +111,8 @@ int prt_close() {
 void interrupt prt_int() {

   unsigned char pcr;

   int *lst_stk;

-  float temp;

 

+  disable();

   lst_stk = _BP;

 

   // if no more char to write

@@ -131,7 +128,6 @@ void interrupt prt_int() {
 	*(prt.event_flag) = 1;

 

 	// call io-complete

-	// TODO: the book says (pg 86) that there should be stuff passed to io-complete

 	IO_complete(PRT, lst_stk);

 

 	// send end of interrupt signal

@@ -153,4 +149,5 @@ void interrupt prt_int() {
 

   // send EOI

   outportb(0x20, 0x20);

+  enable();

 }
\ No newline at end of file
diff --git a/prog/COMPRT.MPX b/prog/COMPRT.MPX
new file mode 100644
index 0000000..0cf0bc0
--- /dev/null
+++ b/prog/COMPRT.MPX
diff --git a/prog/CPUCOM1.MPX b/prog/CPUCOM1.MPX
new file mode 100644
index 0000000..007a6ba
--- /dev/null
+++ b/prog/CPUCOM1.MPX
diff --git a/prog/CPUCOM2.MPX b/prog/CPUCOM2.MPX
new file mode 100644
index 0000000..8c412d7
--- /dev/null
+++ b/prog/CPUCOM2.MPX
diff --git a/prog/CPUCOM3.MPX b/prog/CPUCOM3.MPX
new file mode 100644
index 0000000..0eee0f6
--- /dev/null
+++ b/prog/CPUCOM3.MPX
diff --git a/prog/CPUCON.MPX b/prog/CPUCON.MPX
new file mode 100644
index 0000000..cb62708
--- /dev/null
+++ b/prog/CPUCON.MPX
diff --git a/prog/CPUPRT1.MPX b/prog/CPUPRT1.MPX
new file mode 100644
index 0000000..fe9cc56
--- /dev/null
+++ b/prog/CPUPRT1.MPX
diff --git a/prog/CPUPRT2.MPX b/prog/CPUPRT2.MPX
new file mode 100644
index 0000000..ce7efee
--- /dev/null
+++ b/prog/CPUPRT2.MPX
diff --git a/prog/IDLE.MPX b/prog/IDLE.MPX
new file mode 100644
index 0000000..b3d5a4e
--- /dev/null
+++ b/prog/IDLE.MPX
diff --git a/prog/IOCOM1.MPX b/prog/IOCOM1.MPX
new file mode 100644
index 0000000..93b93a4
--- /dev/null
+++ b/prog/IOCOM1.MPX
diff --git a/prog/IOCOM2.MPX b/prog/IOCOM2.MPX
new file mode 100644
index 0000000..bba7788
--- /dev/null
+++ b/prog/IOCOM2.MPX
diff --git a/prog/IOCOM3.MPX b/prog/IOCOM3.MPX
new file mode 100644
index 0000000..439c564
--- /dev/null
+++ b/prog/IOCOM3.MPX
diff --git a/prog/IOCOM4.MPX b/prog/IOCOM4.MPX
new file mode 100644
index 0000000..cd1879d
--- /dev/null
+++ b/prog/IOCOM4.MPX
diff --git a/prog/IOCOMPRT.MPX b/prog/IOCOMPRT.MPX
new file mode 100644
index 0000000..c326963
--- /dev/null
+++ b/prog/IOCOMPRT.MPX
diff --git a/prog/IOCON.MPX b/prog/IOCON.MPX
new file mode 100644
index 0000000..4f831a4
--- /dev/null
+++ b/prog/IOCON.MPX
diff --git a/prog/IOPRT1.MPX b/prog/IOPRT1.MPX
new file mode 100644
index 0000000..8a76d99
--- /dev/null
+++ b/prog/IOPRT1.MPX
diff --git a/prog/IOPRT2.MPX b/prog/IOPRT2.MPX
new file mode 100644
index 0000000..258ebf7
--- /dev/null
+++ b/prog/IOPRT2.MPX
diff --git a/prog/IOPRT3.MPX b/prog/IOPRT3.MPX
new file mode 100644
index 0000000..720371b
--- /dev/null
+++ b/prog/IOPRT3.MPX
diff --git a/prog/NULL.MPX b/prog/NULL.MPX
new file mode 100644
index 0000000..6c6a6a2
--- /dev/null
+++ b/prog/NULL.MPX
diff --git a/sys_sppt.c b/sys_sppt.c
index c5b784e..6c4923c 100644
--- a/sys_sppt.c
+++ b/sys_sppt.c
@@ -44,9 +44,11 @@ void sys_init()
 

 void sys_exit()

 {

+  disable();

   // restore the clock

   clock_close();

 

+  // close IO devices

   com_close();

   con_close();

   prt_close();

@@ -54,6 +56,7 @@ void sys_exit()
   /* restore interrupt vector 60 and exit */

   setvect(0x60,vect60);

 

+  enable();

   exit();

 }

 

@@ -62,22 +65,33 @@ void interrupt dispatch()
 {

  disable();

  if (DEBUG_PRINTS) {printf("in dispatch \n ");}

- // TODO fix this.. .cop is null when we start

+

  cop = ready_queue_locked;

 

+ // kill zombie processes

+ while (cop->state == ZOMBIE) {

+   remove_pcb(&ready_queue_locked, cop);

+   freemem(cop->loadaddr);

+   free_pcb(pcb_list, cop);

+   cop = ready_queue_locked;

+ }

+

  // skip over suspended processes

  while (cop != NULL && cop->suspend == SUSPENDED) {

    cop = cop -> next;

  }

+

  if (DEBUG_PRINTS){

- if (cop == NULL) {

-   printf("!!cop null?!!!\n");

- } else {

-   printf("cop - %s\n", cop->name);

- }

+   if (cop == NULL) {

+	 printf("!!cop null?!!!\n");

+   } else {

+	 printf("cop - %s\n", cop->name);

+   }

  }

 

  remove_pcb(&ready_queue_locked, cop);

+ cop->state = RUNNING;

+

  enable();

  _SP = cop -> stack_ptr;

 

@@ -104,10 +118,9 @@ void interrupt sys_call()
 

 	// find out if the process wants to die... and kill it

 	if (parm_add->op_number == EXIT_CODE) {

-	  strcpy(cop->name,"averill");

-	  //TODO: CHECK IF THE PCB HAS IO PENDING

 	  freemem(cop->loadaddr);

 	  free_pcb(pcb_list, cop);

+	  // NOTE: the process just made this sys_req so it cannot have any io

 	} else {

 	  IO_sched(cop);

 	}