Added

code/central44t.c

@@ -0,0 +1,177 @@
+#include <sys/ipc.h> 
+#include <sys/types.h> 
+#include <sys/msg.h> 
+#include <stdio.h>
+#include <stdlib.h> 
+#include <unistd.h> 
+#include <semaphore.h>
+
+#define NUM_PROCESSES 4
+
+struct mInfo{ 
+    long priority; //message priority 
+    int temp; //temperature 
+    int pid; //process id 
+    int stable; //boolean for temperature stability 
+};
+
+struct mInfo msgp[2]; 
+struct mInfo cmbox[2];
+
+struct pInfo{ 
+    int mailbox; 
+    int initTemp; 
+    int p_Num; 
+    int p_Range; 
+    int counter; 
+    int g_Num; 
+};
+
+int j = 0;
+
+void *calc_temp(void * arg) { 
+    struct pInfo *p = (struct pInfo*)arg;
+    //Set up local variables 
+    //counter for loops
+    int i, result, length, status, temperature;
+
+    //central process ID
+    int uid = 0;
+
+    //mailbox IDs for all processes 
+    int msqid[NUM_PROCESSES];
+
+    //boolean to denote temp stability 
+    int unstable = 1;
+
+    //array of process temperatures 
+    int tempAry[NUM_PROCESSES];
+
+    //Create the Central Servers Mailbox 
+    int msqidC = msgget(p->mailbox, 0600 | IPC_CREAT);
+
+    for(i = p->p_Num; i <= p->p_Range; i++){ 
+        msqid[(p->counter-1)] = msgget((p->mailbox + i), 0600 | IPC_CREAT); 
+        p->counter++; 
+    }
+
+    //Initialize the message to be sent 
+    msgp[p->g_Num].priority = 1; 
+    msgp[p->g_Num].pid = uid;
+
+    msgp[p->g_Num].temp = p->initTemp;
+    msgp[p->g_Num].stable = 1;
+
+    /* The length is essentially the size of the structure minus sizeof(mtype) */ 
+    length = sizeof(struct mInfo) - sizeof(long);
+
+    //While the processes have different temperatures 
+    while(unstable == 1){
+        int sumTemp = 0; //sum up the temps as we loop 
+        int stable = 1; //stability trap
+
+        // Get new messages from the processes 
+        for(i = 0; i < NUM_PROCESSES; i++){ 
+            result = msgrcv( msqidC, &cmbox[p->g_Num], 
+            length, 1, 0);
+
+            /* If any of the new temps are different from the old temps then we are still unstable. Set the new temp to the corresponding process ID in the array */
+            if(tempAry[(cmbox[p->g_Num].pid - 1)] != cmbox[p->g_Num].temp) { 
+                stable = 0; 
+                tempAry[(cmbox[p->g_Num].pid - 1)] = cmbox[p->g_Num].temp; 
+            }
+
+            //Add up all the temps as we go for the temperature algorithm 
+            sumTemp += cmbox[p->g_Num].temp;
+        }
+
+        /*When all the processes have the same temp twice: 1) Break the loop 2) Set the messages stable field to stable*/
+        if(stable){ 
+            unstable = 0; 
+            msgp[p->g_Num].stable = 0; 
+        }
+        else { //Calculate a new temp and set the temp field in the message 
+            int newTemp = (msgp[p->g_Num].temp + 1000*sumTemp) / (1000*NUM_PROCESSES + 1);
+            usleep(100000); 
+            msgp[p->g_Num].temp = newTemp; 
+            printf("The new temp in GROUP %d is: %d\n",p->g_Num,newTemp); 
+            temperature = newTemp; 
+        }
+
+        /* Send a new message to all processes to inform of new temp or stability */ 
+        for(i = 0; i < NUM_PROCESSES; i++){ 
+            result = msgsnd( msqid[i], &msgp[p->g_Num], length, 0); 
+        }
+    }
+
+    //Remove the mailbox 
+    status = msgctl(msqidC, IPC_RMID, 0);
+
+    //Validate nothing when wrong when trying to remove mailbox 
+    if(status != 0){ 
+        printf("\nERROR closing mailbox\n"); 
+    } 
+
+    pthread_exit(temperature);
+}
+
+int main(int argc, char *argv[]) { 
+    struct timeval t1, t2; 
+    double elapsedTime;
+
+    // start timer 
+    gettimeofday(&t1, NULL);
+
+    int i = 0; 
+    int tempg1, tempg2;
+
+    printf("\nStarting Server...\n");
+
+    //Validate that a temperature was given via the command line 
+    if(argc != 5) { 
+        printf("USAGE: Too few arguments --./central.out Temp"); 
+        exit(0); 
+    }
+
+    struct pInfo process[2];
+
+    /* First Group */ 
+    process[0].mailbox = atoi(argv[3]); 
+    process[0].initTemp = atoi(argv[1]); 
+    process[0].p_Num = 1; 
+    process[0].p_Range = 4; 
+    process[0].counter = 1; 
+    process[0].g_Num = 0;
+
+    /* Second Group */ 
+    process[1].mailbox = atoi(argv[4]); 
+    process[1].initTemp = atoi(argv[2]); 
+    process[1].p_Num = 5; 
+    process[1].p_Range = 8; 
+    process[1].counter = 1; 
+    process[1].g_Num = 1;
+
+    pthread_t thread[2];
+
+    /* Thread Creation */ 
+    pthread_create(&thread[0], NULL, &process, &process[0]); 
+    pthread_create(&thread[1], NULL, &process, &process[1]);
+
+    /* Wait for all threads to finish before continuing */
+    pthread_join(thread[0], (void **)&tempg1); 
+    pthread_join(thread[1], (void **)&tempg2);
+
+    printf("Temperature Stabilized in Group1: %d \n", tempg1); 
+    printf("Temperature Stabilized in Group2: %d \n", tempg2);
+
+    // stop timer 
+    gettimeofday(&t2, NULL);
+
+    // compute and print the elapsed time in millisec 
+    elapsedTime = (t2.tv_sec - t1.tv_sec) * 1000.0; // sec to ms 
+    elapsedTime += (t2.tv_usec - t1.tv_usec) / 1000.0; // us to ms
+
+    printf("The elapsed time is %fms\n", elapsedTime);
+
+    return EXIT_SUCCESS;
+}

code/external44t.c

@@ -0,0 +1,72 @@
+#include <sys/ipc.h> 
+#include <sys/types.h> 
+#include <sys/msg.h> 
+#include <stdio.h> 
+#include <stdlib.h> 
+#include <unistd.h>
+
+struct { 
+    long priority; //message priority 
+    int temp; //temperature 
+    int pid; //process id 
+    int stable; //boolean for temperature stability 
+} msgp, cmbox;
+
+//MAIN function 
+int main(int argc, char *argv[]) {
+
+    /* Validate that a temperature and a Unique process ID was given via the command */
+    if(argc != 4) { 
+        printf("USAGE: Too few arguments --./central.out Temp UID"); 
+        exit(0); 
+    }
+
+    //Setup local variables 
+    int unstable = 1; 
+    int result, length, status; 
+    int initTemp = atoi(argv[1]); 
+    int uid = atoi(argv[2]); 
+    int mailbox = atoi(argv[3]);
+
+    //Create the Central Servers Mailbox 
+    int msqidC = msgget(mailbox, 0600 | IPC_CREAT);
+
+    //Create the mailbox for this process and store it's IDs 
+    int msqid = msgget((mailbox + uid), 0600 | IPC_CREAT);
+
+    //Initialize the message to be sent 
+    cmbox.priority = 1; 
+    cmbox.pid = uid; 
+    cmbox.temp = initTemp;
+    cmbox.stable = 1;
+
+    /* The length is essentially the size of the structure minus sizeof(mtype) */ 
+    length = sizeof(msgp) - sizeof(long);
+
+    //While all the processes have different temps 
+    while(unstable == 1){
+        //Send the current temp to the central server 
+        result = msgsnd( msqidC, &cmbox, length, 0);
+
+        //Wait for a new message from the central server 
+        result = msgrcv( msqid, &msgp, length, 1, 0);
+
+        //If the new message indicates all the processes have the same temp 
+        //break the loop and print out the final temperature 
+        if(msgp.stable == 0) { 
+            unstable = 0; 
+        }
+        else { //otherwise calculate the new temp and store it 
+            int newTemp = (10*cmbox.temp + msgp.temp) / 11; 
+            cmbox.temp = newTemp; 
+        }
+    }
+
+    //Remove the mailbox 
+    status = msgctl(msqid, IPC_RMID, 0);
+
+    //Validate nothing when wrong when trying to remove mailbox 
+    if(status != 0){
+        printf("\nERROR closing mailbox\n");
+    }
+}

code/multi

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+./external44t 10 1 123456700 & 
+./external44t 100 2 123456700 & 
+./external44t 1000 3 123456700 & 
+./external44t 10000 4 123456700 & 
+./external44t 50 5 123456710 & 
+./external44t 500 6 123456710 & 
+./external44t 5000 7 123456710 &
+./external44t 50000 8 123456710 & 
+./central44t 10 100 123456700 123456710 &